摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent.of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000369

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

OBITUARY WILLIAM JOSEPH DIBDIN 371 The Adulteration of Conserves with Special Reference to Pectin and Agar-agar, BY JOHN KING F.I.C. (Read at the Meeting May 6 1925.) LEGAL AsPEcTs.-There are in this country no legal standards for conserves, and legal proceedings for adulteration are therefore normally instituted under the Sale of Food and Drugs Act 1875 Section 6. It is extremely difficult in the absence of such standards for an analyst to adopt any representative procedure or to standardise his methods with any degree of exactness so as to detect adulteration of an order that will secure the conviction of an offender. The section mentioned above requires a vendor to sell the substance demanded, and the purchaser not to be prejudiced in regard to its quality. Authoritative opinions as to the nature of conserves are not very helpful, Webster’s dictionary often quoted in the courts defines jam as a “conserve of fruit boiled in mass with sugar and water.” There is a notable paucity of legal cases dealing with conserves and High Court decisions have in some important cases quashed magisterial convictions, as in the glucose case mentioned later.The Sale of Food Order of August 1921 No. 1305 Part IV. which dealt with conserves has been amended by No. 1883. The sub-clauses 9 10 and 13 being revoked no longer constitute legal standards but nevertheless they still serve the useful purpose of having expressed an authoritative opinion. Thus it may b 372 KING THE ADULTERATION OF CONSERVES WITH assumed that a purchaser of marmalade is prejudiced by the inclusion of fruits and vegetables other than citrus fruits unless these are specifically mentioned on the label.No definition of citrzcs fruit was given in this order though the American Food Inspection Decision 182 (ANALYST 1921 46 479) lays down standards. Old and well-known trade customs and methods are generally not held to fall under the meaning of the term adulteration. Thus the inclusion of a considerable percentage of glucose has been held by the High Court not to constitute a prejudice to the purchaser it being a well recognised trade practice. It is certain however, that the average purchaser would if he were aware of the fact be highly indignant at the inclusion of a chemically prepared substance in place of the sugar which he would normally expect to be the sweetening ingredient of jam.The use of “stiffeners” appears to fall under a different category as these are added with the direct object of hiding inferiority. CHEMICAL AND PHYSICAL ASPECTS.-byrom the manufacturer’s point of view, the ideal to be aimed at is the production of the jam of maximum saleability, at the minimum cost. The extent of inclusion of the least costly fruits may be held to be limited by the Order previously mentioned but the amount of water that can be added is limited by the saleability of the article. The sweetening matters mostly used are refined sugar glucose and “sprayed sugars.” The last-named which are very widely used are refined sugars sprayed with 5 to 10 per cent. of a 60-70 per cent. solution of artificially prepared invert sugar.They are considered sweeter and are cheaper than a pure cane sugar of similar polarisa-tion and jams prepared from them have less tendency to crystallise on storage. Glucose is reputed to reduce the setting power if present in large quantities. The problem from the adulterator’s standpoint resolves itself mainly into (a) the inclusion of fruits and vegetables other than those specified in the description; (b) the inclusion of the least costly fruits in an unwarrantable proportion; (c) the production of a conserve of a reasonable consistence from the minimum of fruit and sugar as it is obvious that the public will consider firmness as a criterion of the amount of fruit present. Consistence in a properly made jam depends almost entirely on the pectin content and the presence of cellylar structure.Pectin being a colloid should, for the purpose of producing firmness be brought into the gel form as much as possible and manufacturers have resorted to many methods for this purpose. The addition of 1 per cent. of phosphoric tartaric or citric acid will often do much to promote gelatinisation. SPECIAL FUNCTIONS OF PECTIN IN RELATION TO CONSERVES WITH RECENT WORK IN CONNECTION WITH JELLIES ETC.-A notable amount of work has been done in America on pectin in relation to the conserve industry. La1 Singh (1) has shown that a definite relationship exists between the amount of acid present in fruit juices and the amount of sugar necessary to form jellies. Between certain limits, the greater the acidity of the juice and the greater the percentage of pectin the lower the amount of sugar required.It is therefore desirable to increase the acidit SPECIAL REFERENCE TO PECTIN AND AGAR-AGAR 37.3 of the juice to the maximum limit compatible with taste in order to save sugar. By increasing the pectin in a juice from 0.9 to 1.5 per cent. a jelly maker can easily save over 15 per cent. of sugar. He has estimated that waste lemon peel from citric acid factories could yield over 90 lbs. of pectin per ton of peel. F. Hardy (2) has investigated the effect of hfferent processes for the ex-traction of pectin from lime rind and has concluded that the H-ion concentration influences widely both the amount extracted and the jellying power of the extract. Johnstin and Denton (3) have pointed out the relationship between the viscosity and jellying power applied to citrous extracts and H.A. Noyes (4) has shown that different processes for the manufacture of jams and jellies have great effects on the jellying power the "vacuum cook process" being the most efficient from this standpoint. It seems highly probable therefore in view of the above work, that great changes in the processes employed in the conserve industry may be expected in the future. A certain amount of information may be obtained as to the nature of the acids present by the electrical method of titration of a filtered solution of the conserve. The neutralisation curves however should be interpreted with caution owing to the presence of substances having a buffer action. Curves obtained by using jams of known constitution might conceivably be used as standards.The slow decomposition of pectin even by boiling citric and malic acids in the concentration usually met with in conserves as described later shows that the natural acid content of fruit should be carefully taken into account in jam manu-facture. Where the natural pectin content is insufficient the gelatinising power is often augmented by gelatin agar-agar or possibly even by pectin itself obtained from pomace. Crude pectin has already been placed on the market and a powder described as " pectin jelly," containing apple pectin on examination was found to be correctly described as such. The addition of gelatin is readily detected by the addition of picric acid to a solution of the matter precipitated by alcohol.Where gelatin is added the acid content of the jam is of extreme importance. Baker found that a jelly made from gelatin with acidity of 0.35 per cent. as acetic acid would set easily at ordinary temperatures but that at 0.71 per cent. acidity the same concentration of gelatin gave no gelatinisation even at 0" C. The detection and determination of agar-agar presents such difficulties and the methods described in the literature are so unreliable that it seemed worth while to devise a better method. DETECTION DETERMINATION AND PROPERTIES OF PECTIN AND AGAR-AGAR.-The methods at present in use for the detection and determination of agar-agar are microscopical and physical. Parkes (5) suggests that as the solution temperature of agar-agar is 80" C.that of pectin being much lower the conserve could be freed from its natural pectin by washing with lukewarm water and filtering. The dkbris on the filter could then be boiled and refiltered while hot when all the agar-agar but none of the pectin would appear in the filtrate. Recent work b 374 KING THE ADULTERATION OF CONSERVES WITH Schryver Card and Haynes and by Tutin has shown that it is almost impossible to wash the whole of the pectin from fruit tissue even on very prolonged treatment. So difficult is this that the former workers have described a more difficultly soluble form of pectin which they call protopectin and which could not be washed from fruit tissue by ordinary means (6). Tutin (7) has shown however that this is probably merely a question of cell rupture and that protopectin does not in fact exist as a body separate from pectin.This work seems to show that provided some unruptured cells exist in a con-serve (and microscopical examination almost always shows this to be the case), washing by lukewarm water cannot entirely take out the pectin. Further boiling would inevitably wash out more and this might prove a source of error in this method. The microscopical method of detection of agar-agar is discussed later. Agar-agar is obtained from various closely related seaweeds in the vicinity of Japan Hongkong and Australia. The purified material has been carefully examined and is known chemically as S-galactan or 8-gelose. On degradation by acid arabinose and galactose have been recognised amongst the products.It is readily soluble in water from 80" C. upwards but it is insoluble in alcohol and acetone. Gelose has never been obtained in a crystalline state and never quite free from nitrogen although Klostermann claims to obtain nitrogen-free agar-agar by hydrolysis with alcoholic potash. A somewhat similar substance has been prepared from carrageen moss by Haas and has been found to contain the radicle do - so2*o \Ca \o .so,.o/ since it gives no precipitate with barium chloride until boiled with concentrated hydrochloric acid (8). Gelose has been examined by Fairbrother and Mastin and independently by several other workers and has been found also to contain this radicle (9). The ester has been decomposed by hydrochloric acid in a large number of samples and the sulphate estimated by precipitation as barium sulphate.The results were fairly constant varying only from 2-8 to 2.5 per cent. as SO,. This reaction has been used to determine the agar-agar in a conserve as described later. Pectins from such widely separated sources as apple rhubarb mangel-wurzel, etc. have been shown by von Fellenburg Tutin Tollens and Card and Haynes to be identical. Pectin is readily hydrolysed in the cold by dilute sodium hy-droxide to the sodium salt of pectic acid Tutin believing pectin to be the dimethyl-isopropenyl ester of pectic acid (10). Schryver and Haynes have assigned the formula &H,O, to this acid and Card and Haynes have shown that it can be precipitated quantitatively even in very dilute solution from acetic acid solution as the calcium salt (11).It will be seen therefore that if the pectin from conserves can be precipitated in this way leaving the agar-agar unchanged a method for the detection of the latter can easily be devised. In order to test this possibility solutions of agar-agar from several sources were treated in the cold with sodiu SPECIAL REFERENCE TO PECTIN AND AGAR-AGAR 375 hydroxide at varying concentrations acidified with acetic acid and calcium chloride added. EXPERIMENTAL.-The completeness of the precipitation of pectin from commercial conserves and its quantitative aspect were studied as follows :-Fifty grms. of various jams were heated on a water bath in a 500 C.C. beaker, and thoroughly disintegrated by squeezing with a flat-ended glass rod.Where difficulty was experienced owing to the presence of whole fruit the jam was ground little by little with clean sand in a mortar until completely broken up. Hot 95 per cent. alcohol or industrial methylated spirit was then added little by little, with constant stirring until the volume reached 300 C.C. I t was then kept at about 50" C. and the mass at the bottom frequently stirred with the rod until inspection showed no gelatinous particles (Q to 2 hours). By this means the sugary matter was obtained in solution and the pectin precipitated. The contents of the beaker were filtered through coarse filter paper on a Buchner funnel suction being used only towards the end of the filtration. The filter and its contents were well washed with warm 95 per cent. alcohol and washed back into the beaker re-treated with 300 C.C.of hot alcohol and refiltered. The pectin was dissolved from the residue by boiling water the solution being filtered and cooled. Dilute sodium hydroxide solution was added until an approximate concentration of 0.02 N was obtained and the mixture was allowed to stand one hour in order to complete hydrolysis. Sufficient acetic acid was added to give a concentration of 0.1 N free acid and then 20 C.C. of 10 per cent. calcium chloride solution. After standing one hour the precipitate was boiled for a few minutes and filtered through a tared fluted filter paper the filtrate being treated as below. The gelatinous precipitate was well washed with boiling water washed back into the beaker re-boiled with 200 C.C.of water and refiltered through the same filter paper. This paper had been thoroughly washed with boiling water dilute acetic acid and more water and dried till constant in weight. The precipitate was dried and weighed. The amounts of pectin insoluble in 95 per cent. of alcohol and precipitated by calcium chloride in some common jams were as follows:-Plum and apple 0.13; blackberry and apple 0.25; plum 0.46; damson 0.53; raspberry 0.31; and gooseberry 0.45 per cent. (expressed as calcium pectate). It will be seen by these results that jams differ widely as regards pectin content and this suggests a method of quantitative determination in mixtures. In the absence of standard jams of this type the author has not been able to pursue this possibility. The filtrate from the above described precipitation was neutralised sodium hjrdroxide added until the alkalinity was 0.02 N and the former process repeated.An addition of calcium chloride gave no further precipitate indicating absence of pectin. The solution after being neutralised was evaporated to very small bulk and cooled at intervals during the concentration to test gelatinisation. None could be obtained. THE HYDROLYSIS OF AGAR-AGAR BY AcIDs.-Many jams known to be free from agar-agar were mixed with a known quantity of a solution of agar-agar in In no case was there any precipitate 376 KIPr’G THE ADULTERATION OF CONSERVES WITH water. The process described above was repeated with these adulterated jams. The filtrate from the calcium pectate on evaporation gave typical gels in some, but not in all cases.It became necessary therefore to study the effect of acetic and other organic acids on agar-agar. This was done by boiling 0-5 grm. at various dilutions under a reflux condenser for various times cooling and diluting to 200 C.C. and titrating the reducing sugars formed with Fehling’s solution the percentage of reducing sugar formed being a measure of decomposition. An acetic acid solution of potassium ferrocyanide was used as an external indicator. The results are embodied in the following table :-Agar 1. 2. 3. Time of hydrolysis. 30 mins. ,, 15 mins. 1 hour 2 hours 4 hours 2 1 <6ur 2 hours 4 1 , 2 Y , 3 7 , J > Concentration and acid used. 3 per cent. HCl 9 9 ,, ,> ,> 1 5 per cent.citric 1 per cent. citric 1 per cent. malic 1 per cent. tartaric 5 per cent. acetic 1 per cent. citric 9 , 9 , Reducing sugars formed by hydrolysis, expressed as hexose . Per Cent. 49.6 46.3 47 -0 44 -4 47 -0 47 a 0 47.2 47 -2 43.5 41.3 46.6 46.6 23.2 44.4 It is to be inferred from these results that agar-agar is completely decomposed by tartaric citric and malic acids in four hours at a concentration of 1 per cent. acid and that higher concentrations very rapidly decompose this substance. The hydrolysis of agar-agar by organic acids at a concentration likely to be found in jams and conserves generally makes the addition unprofitable unless added immediately before the mass is cooled. In view of these results it became necessary to modify the procedure in order to obtain satisfactory results with small quantities of agar-agar.The filtrate from the calcium pectate was therefore immediately neutralised before con-centration which was continued only to 50 c.c. after which 400 C.C. of cold 95 per cent. alcohol were added and the whole allowed to stand overnight in order to precipitate the agar-agar. It was then filtered through a fluted paper washed with 50 per cent. and then with 25 per cent. of cold alcohol. The filter and contents were then boiled with water filtered and concentrated. No difficulty was ex-perienced in obtaining satisfactory gelatinisation even from 0.1 per cent. agar-agar. It was hoped that the original residue precipitated by alcohol from a conserve would be sufficiently free from sugar to merit investigation as to the comparative hydrolysis of agar-agar and pectin by acids.After a short trial the attempt wa SPECIAL REFERENCE TO PECTIN AND AGAR-AGAR 377 abandoned as such a method would often be misleading since the difficulty of testing for commercial sweetening agents possibly occluded under such cir-cumstances was found to be very great. Not only did presumably pure pectin reduce Fehling’s solution to an appreciable extent but it was found that pectin was hydrolysed by organic acids of a strength previously found to decompose agar-agar. THE HYDROLYSIS OF PECTIN BY ACIDS NORMALLY OCCURRING IN FRUITS.-Crude pectin was dissolved in water hydrolysed in the cold by 0.02 N NaOH for one hour and acetic acid added until neutral to litmus.It was boiled filtered and cooled acetic acid added until 0.1 N and 20 C.C. of 10 per cent. calcium chloride added. After standing one hour the precipitate was boiled filtered and weighed in the usual way as calcium pectate. A similar weight of the same crude pectin was next boiled under a reflux condenser with malic and citric acids and the re-sidual pectin determined as above. Original weight of pure pectin taken expressed as calcium pectate = 0.1155 grm. Time Concentration of and acid used. boiling. Hours. Citric 2 per cent. 3 Malic 1 per cent. J ? Ma.l;,c 2 per cent. I Citric 1 per cent. 9 Pectin not decomposed expressed as calcium pectate. Grm. 0.0730 0.0745 0.0895 0 -0865 Pectin decomposed (by difference).Grm. Per Cent. 0.0425 37.0 0.0410 35.5 0.0260 22.5 0.0290 25.1 These results show that prolonged boiling of jam is most undesirable owing to the decomposition of pectin. It explains the great difficulty experienced by the housewife in obtaining crab-apple jelly of good setting quality at times the pectin content being low and the acidity often 2 per cent. and over. In the presence of liquid glucose and gelatin it was found necessary to make a slight modification of the procedure as the dextrin and gelatin precipitated by alcohol treatment congealed with the pectin to a sticky mass. In the case of gelatin the precipitate produced by alcohol was dissolved in hot water the solution cooled the gelatin removed by precipitation by picric acid and the excess of this by white of egg which was then precipitated by boiling.Dextrin was removed by treatment with cold water but the subsequent filtration proved troublesome. DETERMINATION OF AGAR-AGAR.-It will be obvious from the foregoing that any methods for determining agar-agar in a conserve must be limited to evaluating that which remains undecomposed by the acids present and this may not under certain circumstances be a correct criterion of the amount originally added. A method for the determination of this undecomposed agar-agar was devised Ca which is completely by taking advantage of the presence of the group S0, 378 KING THE ADULTERATION OF CONSERVES WITH hydrolysed on prolonged boiling with hydrochloric acid into the ionised SO, radicle which can be precipitated in the normal way by barium chloride.If the amount of jam available is limited the agar-agar precipitated by alcohol for the qualitative examination may be utilised but it is preferable to take a fresh quantity and proceed as follows:-One hundred grms. of jam or more if only slightly adulterated are carefully freed from sugar as previously described. The residue on the Biichner funnel is boiled for some minutes in 200 C.C. of water filtered washed re-boiled and re-filtered pressure being used when required. It is essential to keep the fluid over 80" C. during filtration to ensure that all the agar-agar passes into the filtrate. This is concentrated to 300 c.c. and an aliquot portion (say 100 c.c.) taken for the determination of free sulphate by the usual method.Care should be taken by deferring the addition of hydrochloric acid until the last possible moment not to decompose any agar-agar. The remaining 200 C.C. are concentrated to 100 c.c., and an equal bulk of concentrated hydrochloric acid is added. The mixture is boiled for 6 hours more acid being added when necessary. Finally it is con-centrated to 25 c.c. then diluted to 300-400 c.c. and filtered hot. Barium chloride is added and the whole allowed to cool and stand overnight as the barium sulphate does not precipitate quickly. Washing filtering and incinerating may then be carried out as usual and the weight of agar-agar found from the formula:-15 [ ( a - 2 b ) ] where a represents weight of barium sulphate from the total sulphate from the 200 c.c.and b the weight of barium sulphate from the free sulphate in the 100 C.C. Fifteen is chosen as the factor which represents slightly less than the maximum of barium sulphate obtained by hydrolysis and precipitation of sulphate from agar-agar. The difficulty of effecting rapid precipitation from the hydrolysed agar-agar and pectin was found to be due to the degradation products of the pectin. On boiling pectin for some hours with concentrated hydrochloric acid diluting and filtering the resulting liquid was found to delay for many minutes the pre-cipitation of barium sulphate even from concentrations far greater than those encountered in agar-agar determinations. Typical results obtained were as follows :-1. 0.5 grm. of agar-agar in 100 grms. of gooseberry jam gave 0.0092 grm.of BaSO for (b) and 0.0448 grm. for (a) hence agar-agar = 0.59 grm. 0.5 grm. of agar-agar in 100 grms. of strawberry jam gave 0.0078 grm. of BaSO for (b) and 0.0380 grm. for (a) hence agar-agar = 0.504 grm. 0.5 grm. agar-agar in 50 grms. of gooseberry jam on hydrolysis of both (a) and ( b ) gave 0.0520 grm. of BaSO,." Thus the sulphate given by hydrolysis of the agar-agar = 0.0342 grm. which is equi-valent to 0.51 grm. of agar-agar. 2. 3. * Fifty grms. of jam treated in the same way before hydrolysis gave 0.0178 grm. of BaSO, SPECIAL REFERENCE TO PECTIN AND AGAR-AGAR 379 Analytical figures are given by F. Hartel and J. Solling (Zeitsch. Untersuch. Nahr. Genussm. 1911 21 168-196) for most common jams for insoluble matter, soluble solids acidity sucrose sugar-free extractives mineral matter and al-kalinity of the mineral matters.MICROSCOPICAL EXAMINATION OF CONSERVES.-The microscopical examina-tion of a conserve for the identification of fruit and vegetables is of extreme im-portance and it very often furnishes the only evidence of adulteration. Many books of reference such as those of Winton Konig Schneider Moeller, and Schimper are available which illustrate and describe the microscopical characteristics of a fair number of fruits and vegetables but these are often mis-leading and comparison with known specimens actually isolated from jams is far preferable. The conserve should be thoroughly mixed in a tall beaker with about 50 times its volume of hot water and stirred from time to time until the gelatinous matter is in solution.The fruit dkbris should then be allowed to settle and the clear fluid drawn away through a glass tube by applying gentle suction from a water-pump. The washing and decanting should be repeated if necessary and the whole of the dkbris thrown into a large flat-bottomed porcelain dish. It will then be possible to examine with a hand lens various distinctive objects. These will usually be clear enough for microscopical examination as a water preparation, though occasionally epidermis will need further treatment by chloral hydrate in order to obtain the required transparency. Permanent mounts of specimens required for future reference are best made in glycerin jelly. Specimens isolated by the above treatment will usually require further treatment by washing in hot water.They should then be transferred to a 50 per cent. solution of glycerin in water allowed to drain and mounted in jelly in the usual way. Ringing by gold size on Japan black is essential for permanence. EPIDERMIs-The arrangement size and shape of cells should be noted, together with presence or absence of stomata hairs etc. It should be remembered that the epidermis from fresh fruit is often very different from that in the finished conserve. One should be cautious in assuming epidermis to be glabrous as hairs easily become detached by boiling. Very often a clue is given by a circular or rosette-like arrangement of cells around the base of a hair which may be missing. The best method is that of comparison with epidermis obtained from known jams.As there are not many fruits normally used in jam making whose epidermis will withstand the process of long-continued boiling a suitable collection of per-manent slides is readily made. CELLULAR STRUCTURE.-A little of the conserve itself may be examined directly or after suitable dilution with water or glycerin. The presence of cells, vessels seeds hairs styles etc. should be noted. The large parenchymatous cells of the apple should not be confused with those of the turnip vegetable marrow or banana. These distinctive cells of the apple are sometimes but by no means invariably stained violet with iodine solution. Stone cells arranged in larg 380 KING THE ADULTERATION OF CONSERVES WITH groups may indicate pear or quince. Curious bundles of narrow stone cells in bundles of 6 to 12 occur in the currant.Vessels may indicate apricot peach mangel-wurzel carrot ginger cherry or certain vegetables. Reticulated vessels do not necessarily indicate roots as they are present in cherry apricot and peach. Size is a good guide but comparison is practically essential. SEEDS.-The seeds should be isolated and by the aid of a lens separated into obviously different kinds and dried. These are best examined by an inch objective with a binocular microscope when available and with dark ground illumination and a top light. The differences are very striking and varieties can be easily recog-nised by reference to standards. These can be prepared by isolating seeds from known jams washing drying and mounting loosely in a circular black-backed recess cut in a hard wood slide and protected by a coverslip.It is often stated that the seed content of jams prepared from aggregate fruits is sufficiently constant for a count to be of great value in quantitative work. In recent years much has been done by hybridisation to increase the weight of the fleshy portion of the whole fruit compared with that of the actual seeds so that in modern practice a seed count is of very doubtful value. HAIRs.-The water-washed residue previously examined for epidermis should be separated by centrifuging and studied for detached hairs. In most fruits these are fairly distinctive in size and shape but the general characteristics are sometimes so altered in the process of jam making as to make them unreliable as a means of identification.Prolonged search is often necessary to obtain a complete specimen and it is advisable to secure this as the terminal point often provides valuable information. Care should be taken not to mistake a broken style for a hair. STYLES.-Those of the strawberry raspberry and blackberry are distinctive, and are easily picked out with forceps being 2 to 4 mm. in length. The original quality of the fruit may be questionable; in this case search should be made for fungus growths including yeast cells spores etc. Many of these show up well with Gram’s stain being Gram positive. agar as normally prepared always contains diatoms sponge spicules and other forms of marine origin. The most easily recognised parts of these objects, being composed of silica will persist in any conserve in which agar-agar is used.They are usually somewhat distorted and fragmentary and their isolation and identification is attended by some little difficulty. As little as 0-25 per cent. of agar-agar may produce a marked improvement in the consistence of a conserve, so that a large bulk say 100 grms. should be taken for the test. The direct ignition method of Macara and the sulphuric acid method have proved troublesome with large bulks and the following is to be preferred when a slight amount of adulteration makes it necessary for every diatom to be carefully preserved. THE IDENTIFICATION O F AGAR-AGAR BY THE PRESENCE OF DIATOMS.-Agar SPECIAL REFERENCE TO PECTIN AND AGAR-AGAR 381 One hundred grms. are warmed in a large beaker with concentrated nitric acid on a water bath the acid being added in small portions at intervals in order to avoid excessive frothing.When the sugary matter is decomposed the acid is evaporated to small bulk and the whole of the contents of the beaker washed into a platinum dish. The mass is evaporated to dryness gently ignited until a perfectly white ash is left and this is boiled for a few minutes in dilute nitric acid. The contents of the dish are then washed into a boiling tube and the sediment washed by decantation great care being taken not to lose any diatoms. This is best done by drawing the clear fluid away by means of a pipette attached to a suction pump and applying gentle and steady suction. A few crystals of potassium chlorate are added to the sediment and about 10 C.C.of concentrated sulphuric acid. This is heated for a few minutes in order to decompose any remaining organic matter the presence of which might hide small but important diatoms. The final washing of the diatoms may be done in a small test tube the base of which has been drawn out to about 1 mm. The diatoms should then be con-centrated in a few drops of water only and removed by means of a small dropping pipette to a microscope slide. Any remaining diatoms may be removed by the addition of a few drops more water which is agitated briskly before being drawn into the pipette. The liquid on the slide should be evaporated to dryness and diatoms permanently mounted in situ in styrax as prolonged examination and reference to standards are often necessary.Such standards may be purchased from professional diatomists or may be prepared by igniting shredded agar-agar and washing as above removing individual diatoms from the dry slide by means of a hair to a gummed coverslip and finally mounting in styrax. The natural silica content of certain conserves may be high enough to make the mounting in situ inadvisable in which case selected diatoms may be transferred to a gummed coverslip by means of a hair as mentioned above. Many of the diatoms and spicules described as diagnostic by text-books and various papers are on examination found to exist in non-agar-agar producing localities. Some indeed are quite plentiful round the British coast. Sanft (12) and Marpmann (13) have examined agar-agar from the standpoint of the diatoms which are characteristic but unfortunately neither has considered the possibility of confusion with diatoms from commercial diatomites.Differences are to be expected as the diatoms from agar-agar are essentially of marine formation, whereas commercial diatomites are prepared from diatomaceous deposits from old fresh water lakes or inland seas. The author was fortunate in obtaining the help of Mr. F. W. Payne B.A., who has been kind enough to review the whole subject with the object of laying down characteristics which could be considered specifically diagnostic. He has prepared a list given below of the diatoms found in many specimens of agar-agar. The presence of one or two diatoms included in the list is not necessarily diagnostic, but nevertheless if taken in conjunction with the table of localities quite a small number may afford strong presumptive evidence.Most of these listed diatoms are illustrated in the photomicrograph or reference may be had to Schmidt’s Atlas of the Diatomaceae 382 KING THE ADULTERATION OF CONSERVES WITH As mentioned in the chemical section an attempt to improve a conserve by the addition of agar-agar may fail if the acidity is high and the agar-agar is added at too early a stage in the boiling. In such circumstances chemical tests might fail whereas a microscopic examination should always succeed unless the agar-agar has been ground so finely before use that it is impossible to recognise individual diatoms. Should a manufacturer claim that diatoms found in his conserve are derived from his filters it is suggested that he be called upon to produce a sample.Com-parison of the diatoms would then easily detect similarity or otherwise provided that sufficient diatoms from the conserve are available. DIATOMS IN AGAR-AGAR. Name of Diatom. ACTIONOCYCLUS RALFS vor. GRUN ***ARACHNOIDISCUS ORNATUS E. **BIDDULPHIA PULCHELLA GRAY. "BIDDULPHIA TUOMEYI BAIL. ***CAMPYLONEIS GREVILLEI (W Sm) GRUN. CLIMACOSPHENIA MONILIGERA E. COCCONEIS CORONATA E. *** , HETEROIDEA HANTZSCH * , SCUTELLUM E. *** , SPLENDIDA (Greg) GRUN. *COSCINODISCUS NITIDUS Greg. 1 2 undetermined SP **GRAMMATOPHORA MACILLENTA E. *GLYPHODESMIS WILLIAMSONI (Greg) GRUN **GRAMMATOPHORA MARINA E. ** SERPENTIYA E. *GEPHY;IA MEDIA ARN *HYALODISCUS STELLIGER BAIL., SP **ISTHMIA NERVOSA K. NAVICULA CRABRO E. , FIMBRIATA. E. , LACRIMANS AS. , LYRA VAR. E (GEMMATULA VAR. CL.) **PODOCYSTIS SPATHULATA (SHADB.) V. vH" SURIRELLA DIVES CSTR TRICERATIUM FAVUS E. , PARALLELUM GREV. VAR. Other localities in which found. Manila Cuba Society Is. Smyrna. Africa West Coast of America. Campeachy Bay Brazil Mediterranean, Guano Brazil Madagascar West Coast of California Australia Arabia etc. Cuba W. Africa California. W. Indies Smyma Corsica. Corsica W. Coast of America. Australia New Zealand Colon E. Indies. Ubiquitous. Cuba Scotland California etc. Scotland Colon Alexandria etc. Britain The Levant etc. Scotland California . Ubiquitous. Ubiquitous. Sandwich Is. California. Ubiquitous.North of Europe and America. Common. Gulf of Mexico. Australia. Africa. Common. Society Is. Mauritius Central American Coasts etc. Carpentaria Ray. Ubiquitous. *** denotes. occurring very frequently ** denotes frequently * denotes sparingly and the unstarred diatoms only occurred once in agar-agar. The actual numbers found by F. W. Payne. in examining a large number of samples were approximately *** 100 to 150 ** 10 to 20 * 2 to 6 (in 5 grms. of agar-agar). The author wishes to express his thanks to Mr. F. W. Payne B.A. whose great experience regarding diatoms and whose helpful suggFstions have been most valuable. In conclusion he desires to thank Mr. F. J. Osborn for the many excellent photomicrographs of diatoms which he has been good enough to prepare from time to time and the Government Chemist for permission to publish this paper DIATOMS IN AGAR-AGAR.Easily recognisable are the huge Isthmia (A and B) ; the A rachnoidiscus (1-3) ; Gephyria ( Cocconeis spleazdida (9) ; Navicula gemmatula (13) and Lyra (14) ; Biddulphia Tuomeyi (20 21), Podocystis (27 28) ; the Grammatophora (29-34) ; and Campyloneis (39 40) SPECIAL REFERENCE TO PECTIN AND AGAR-AGAR 383 REFERENCES. I n d . Eng. Chem. 1922 p. 710. Biochein. J . 1924 283. I n d . Eng. Chem. 1923 p. 780. I n d . Eng. Chem. 1923 15 News Edition March 10 p. 3. ANALYST 1921 46 239. Bioclzenz. J. 1922 704. Biochem. J. 1923 510. Biochenz. J. 1921 469. J. Chern. Soc. 1923 1414. Biochem. J. 1923 83. Biochern. J. 1922 60. Zeitsch. nllgern.Osterr. Apoth.- Vereine Wien 1902 NO. 9 pp. 829-232. Zeitsrh. nngew. ,Wikroskopie Bd. 2 1887. GOVERNMENT LABORATORY, CUSTOMS HOUSE E.C.3. DISCUSSION. Mr. L. K. BOSELEY said that acids could increase the gelatinising effect of pectin but they also caused the inversion of sugar; so that it was not possible to increase the percentage of acid without running the risk of inversion. Thus the set of the pectin could not be considered alone. Agar-agar was not used in large quantities on account of its price; the cheaper apple-pectin from the manufacture of cider was probably used in preference. Moreover agar-agar was affected by boiling; 0.7 per cent. of acid a t a temperature of 223 F. was sufficient to destroy it. Mr. T. MACARA disputed the statement that it was possible as stated by Tutin to dissolve out the pectin in the ordinary way.He agreed with Schryver, Sucharipa and others that a considerable proportion of the pectin existed in some fruits at least in an insoluble form. He considered that none of the formulae so far proposed for pectin should be accepted until it had been shown that a single substance had been isolated. The pectins so far described appeared t o be mixtures; consequently analytical methods based on them should only be accepted temporarily. The alcohol precipitation method as advocated by American chemists gave an acid hydrolysis product of the mixed substances, whilst the Carrk and Haynes method gave a lime salt of the acids liberated by saponification of the esters. Neither method gqve the actual pectin present in the solution. With regard to agar he had found Parke’s method decidedly useful. Mr. J. KING in his reply states that the value of high acidity as an accessory factor to gelatinisation lies in its application to the jelly rather than to the jam industry. The acidity of a jam can however be increased without very serious sugar inversion by deferring to the last possible moment the addition of a fruit juice of high acidity to the previously boiled body of a jam. Data on pectin-sugar-acid gels are given in the J . Assoc. Of. Agric. Chemists 1923 7 57. The home market for agar-agar is based mainly on bacteriological requirements. Its use in the Malay States for j elly-making indicates possibilities elsewhere. In reply to Mr. Macara it should be mentioned that the present uncertainty regarding the chemistry of the substances grouped under the name “ pectin,” makes it advisable to remove these entirely before testing for other gelatinising agents by a method such as that of Carrk and Haynes which is not open to criticism as regards completeness of precipitation. The accuracy of the existing methods for determination of pectin is doubtful (cf. J . Assoc. Of. Agric. Chemists 1923 7, 107; 1924 281; and J . Soc. Chem. Ind. l925,44,257T.; ANALYST 1923 48 223)

ISSN:0003-2654    

DOI:10.1039/AN9255000371

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

384 WARE DETECTION OF PLANT PHENOLS BY THE The Detection of Plant Phenols by the Use of Nitrites or Nitric Acid. BY ALAN H. WARE. WITH the exception of Griessmayer’s test for ellagic acid the method used by Procter for detecting ellagitannins and Histed’s employment of nitric acid to distinguish between different kinds of aloins very little use appears to have been made of sodium nitrite nitrous acid or nitric acid for the detection of plant phenols in vegetable substances. The present paper describes a series of new or improved tests for certain plant phenols in which one or other of the reagents named are used. The extractive is heated with sodium nitrite without any added acid. Distinctive results are yielded by phloridzin and ellagitannins. The method is similar to the last but a few drops of very dilute acid are also used and heat is applied only if necessary.Very distinctive results are given by iso-barbaloin (see Curacao aloes etc.) and ellagitannins. Liebermann’s test (concentrated sulphuric acid in a dry tube with a minute crystal of the nitrite are heated with phenolic body) is applied to the pure or crude phenol. Distinctive results are given by the catechins and chrysarobin (purified Goa powder). The method used is similar to the last but a wet tube is used and the nitrite is added in excess of the phenolic body. See catechins and “ tobacco-tannin.” The method is that of Griessmayer’s test for ellagic acid. The test was applied to a large number of plant-phenols but a positive result is ap-parently only given by ellagic acid.For a result which appears at first to be positive but is due to the action of the nitric acid alone see the next paragraph. The solid substance is dissolved in strong nitric acid and heated to about 100” C. It is then diluted with water as in Griessmayer’s test. A very distinctive result is obtained with phloridzin. No distinctive results of any special value were obtained in these tests with any of the following :-Gallic acid gallotannin quercetrin brazilin haematoxylin, salicylic acid or partly purified phlobatannins; and although a very large number of vegetable extractives were tested no other results of much value except those recorded were obtained on testing aqueous extractives by any one of the methods described. It would be tedious to tabulate all the individual negative results given by the last class indicated but they included those obtained with samples containing anthraquinone benzophenone xanthone flavone and flavonol deriva-tives and anthocyanins USE OF NITRITES OR NITRIC ACID 385 A description of the more useful results obtained is described under the following heads and in the order given viz.:-(1) Curacao aloes and commercial aloin; (2) phloridzin; (3) ellagitannins in extractives; (4) the catechins (5) com-mercial chrysarobin and (6) " Tobacco-Tannin." (1) CURACAO (SO-CALLED BARBADOES) ALOES AND COMMERCIAL ALOIN.-A very distinctive and specific reaction due to iso-barbaloin can be obtained by dissolving a little Curacao aloes or of the commercial aloin made from this in sufficient water to give to the solution only a straw-colour and then adding to this solution a few crystals of sodium nitrite and one drop of acetic acid (33 per cent.).If this mixture be shaken in the cold for about one minute a rich pink colour, becoming purplish-red is produced. If dilute alkali (1 per cent. aqueous potassium hydroxide solution) be now rapidly added in sufficient quantity the colour changes to a very pronounced green which remains permanent for a considerable time. Discussion.-The reaction must be due to iso-barbaloin because it is not given by Socotrine or Zanzibar aloes each of which contains both barbaloin and beta-barbaloin but no iso-barbaloin. Cape aloes and Natal aloes give a poor pink coloration but do not yield a definite green on the addition of alkali.It is therefore probable that Natal aloes also contains a trace. The reaction is not given in neutral solution either in the cold or on warming (see phloridzin and ellagitannins). It is more convenient and more delicate than the cupraloin test which also often fails unless careful adjustment of the quantities of the reacting substances is made. A few ellagitannin bodies (containing also gallic-acid tannin) give somewhat similar results but can readily be distinguished by the transiency of the colours given, for with these bodies both the colour given on the addition of acetic acid and that given on the subsequent addition of excess of alkali rapidly become brown; whereas the colours with the aloes and aloin are much more permanent. (2) PHLoRIDzIN.-Phloridzin is a glucoside of phloretin (a phloroglucinol body).It is found in the root-bark of many of the Rosacez particularly that of apple pear and plum trees. It is employed in physiological research to produce glycosuria and is sometimes given in medicine as a substitute for quinine. It is said to yield a fine purple colour with ammonia on exposure to the air but the author finds the following method a much more ready way of identifying it:-Test.-A small quantity of phloridzin and a few crystals of sodium nitrite are shaken with a few C.C. of water in a test-tube and the mixture is then heated and finally boiled for at least a minute. A clear pink colour first appears which becomes almost wine-red and this remains unaltered for a long time. On adding alkali the colour changes to yellow.Another Test.-A little phloridzin is dissolved in strong nitric acid and the solution is then heated to about 100" C. and diluted with water. A pink or wine-red colour is thereby given. Under certain conditions a purplish precipitate may fall. In either case if the mixture be shaken with ether the colouring matter is abstracted and the ether becomes intensely red. The colouring matter Cape aloes is known to contain a little iso-barbaloin 386 WARE DETECTION OF PLANT PHENOLS BY THE produced by this method is not the same as that given in the first test; for that cannot be shaken out from an aqueous solution by means of ether and it is also destroyed by dilute nitric acid. Discussion.-The fact that in the first test the colour can be obtained without the addition of acid and changes to yellow and not to green on the addition of alkali sharply differentiates phloridzin from iso-barbaloin.Ellagitannins under the same conditions give a green colour reaction changed to brown by the addition of alkali. It is probable that the root-barks containing phloridzin would in extractive give the first reaction described but the author has not yet had the opportunity of testing them. Both tests appear to be unusually specific in relation to other plant substances. (3) ELLAGITANNINS IN AQUEOUS EXTRACTIVES.-The use of nitrous acid to detect ellagitannins appears to be due to Procter (Leather Industries Laboratory Book). It was probably suggested by Griessmayer’s reaction for ellagic acid (finally established by A.G. Perkin and Nierenstein (Trans. Chem. SOC. 1905, 87 1412). Very useful results are obtained by Procter’s method under suitable conditions but the method is by no means fool-proof sometimes yields uncertain results and does not always distinguish between bodies which contain but little ellagitannin and those which contain much. The present author finds that the following modifications of Procter’s method give more satisfactory results : (a) Test with Nitrite without added Acid.-The extractive is heated in a test-tube with a few crystals of sodium nitrite the heat being applied gradually by holding the tube a little distance above a small flame. In no case should the liquid be boiled. If the original extractive is strongly coloured it should be diluted with water to leave a distinct but not a marked colour.Under these conditions a very definite green colour reaction is usually readily obtained. (b) Test in the presence of added Acid.-The method is similar to that described under (a) except that about one grm. of powdered acid phosphate of sodium and one drop of 33 per cent. acetic acid or of 10 per cent. hydrochloric acid are added before heating the mixture. The acid phosphate (NaH,PO,) acts as an efficient buffer and its use does away with the necessity for very careful adjustment of relative strength of acid sodium nitrite or extractive used. It will be sufficient if the following readily applied precautions are adopted :-The extractive if necessary must be diluted so that its colour is not too pronounced the quantity of sodium nitrite added in this method should not be more as a rule than twice the bulk of a pin’s head and the acid used should not be far removed from the strength indicated.Usually a beautiful blue or violet colour reaction is given, but if the mixture is heated to too high a temperature a green coloration may be produced. After the blue is obtained the colour is often intensified by cooling the tube under the tap. A better blue or violet is sometimes obtained either by adding another drop of acetic acid after cooling and re-heating gradually as before; or by repeating the test with the acid phosphate but without the acetic or hydrochloric acids. If an intense red colour is given either before heating o USE OF NITRITES OR NITRIC ACID 387 in the very early stages of heating (brown should be given at first) too much sodium nitrite has been used.This can sometimes be remedied by thorough dilution; if not the experiment must be repeated with less nitrite. The appearance of such a red colour however is an indication of ellagitannin and the author often finds it convenient to make a preliminary test for ellagitannins by dissolving a few crystals of sodium nitrite in a little of the extractive on a slab and then placing in the solution some broken crystals of acid phosphate of sodium. If ellagitannin be present an evanescent pink to purple colour appears. In some cases the colour is given by the nitrite alone. Discussion and Results.-There is not the slightest difficulty in getting a beautiful blue or violet colour reaction with a typical ellagitannin extractive, even by the merest tyro at such work.The tests also afford a very convenient method of distinguishing between two different classes of ellagitannin compounds, viz. :-(a) Typical ellagitannin compounds which yield a really good blue or violet colour reaction in the second method; and (b) compounds in which the ellagitannin is either very little in total amount or is relatively little in relation to interfering substances and thus do not give a really good blue or violet colour-reaction. This last class of substance gives however an unmistakable green colour-reaction in one or both of the two methods which have been described; and they often yield a purplish colour in the method in which acetic acid is used.The following tannin-containing compounds fall into class ( a ) viz. :-Divi-divi valonia, Eucalyptus globulus leaves the -kinos from Eucalyptus microcorys and E. maczclata, Knoppern galls pomegranate root-bark and fruit-rind and myrobalans. In class (b) are Basra and Aleppo galls algarobilla and pimento fruits. Negative or negligible reactions with respect to the particular colour reactions under discussion are given by gallotannin Chinese galls sumach red rose petals the bark and leaves of Hamamelis virginica bearberry ( A rctostaphyllos uva-wsi) leaves cloves and logwood; all of which substances are especially characterised by the presence of typical gallic acid derivatives. It should be noted however, that many of the typical ellagitannin-bodies contain also gallic-acid tannins, sometimes in considerable quantity.The presence of gallic-acid tannins does not materially interfere with the specific reaction given by ellagitannins which appear to interact with the nitrite preferentially. This is not the case however with gallic acid; for should this be present in relatively large quantity as in Aleppo and Basra galls it will prevent the obtaining of a good blue or violet colour-reaction with the ellagitannin also present. Some similar phenol (which appears, however to be iron-browning) present in Algarobilla renders it difficult or im-possible to get the typical blue or violet colour reaction with that body, notwithstanding the fact that the tannin present is supposed to be mainly of the ellagitannin class. Pimento berries appear to contain ,both a little phlobatannin and gallic-acid tannin in addition to the ellagitannin.(4) THE CATECH1NS.-The presence of the catechins in such vegetable sub-stances as contain them is of course very easy to detect owing to the readiness with which they may be shaken out from aqueous admixtures by means of ether 388 WARE DETECTION OF PLANT PHENOLS BY THE and the phloroglucin reaction obtained by means of the deal shaving and hy-drochloric acid test (applied to the ethereal solution). It does not however appear to have been recorded that the Liebermann reaction is also readily given by catechins even in the crude condition as obtained by evaporating an ethereal solution made as above described. In this way the presence of catechin in Acacia cutch gambier or guarana can readily be confirmed.The colour given is an in-tense violet as in the case of phloroglucinol itself. (5) ToBACCO-TANNIN.-The author has recently had the opportunity of examining some samples of the partially purified “ tobacco-tannin,” so-called, obtained by Bell’s process. This was kindly sent him by Mr. Ernest Paul from the Chemical Laboratory of the Imperial Tobacco Co. Tobacco-tannin appears to be one of the many pseudo-tannins which in some respects resemble the catechins, but do not give the phloroglucinol reactions referred to above. If however, the Liebermann method be varied as described under (a) in the earlier part of this paper a carmine-purple colour-reaction is given. This appears to be a purely oxidising reaction as an apparently exactly similar reaction is given by dissolving the tannin in sulphuric acid and adding a drop or two of test-solution of ferric chloride.Both phloroglucinol and the catechins resemble tobacco-tannin in giving the carmine-red colour reaction with sulphuric acid and sodium nitrite (excess) in a wet tube; and catechins also give a similar reaction if the ferric chloride be substituted for the nitrite. It should be noted however that all of these reactions given by the catechins in the presence of sulphuric acid may be partly due to the action of the sulphuric acid alone. Procter states in his Laboratory Manual that gambier-catechin dis-solves in sulphuric acid to give an intense purple colour. This is somewhat misleading for this catechin dissolves in cold concentrated acid if water be ex-cluded to give a yellow colour; and it is not until a relatively high temperature is reached that the non-distinctive red first given on heating changes to the characteristic rich crimson-purple.This latter reaction is not given by phloro-glucinol neither is it given by “tobacco-tannin,” so that there is no danger of ascribing results to wrong causes in the case of these two compounds. Since phloridzin shows a transient tendency to give a similar reaction under the con-ditions just described it is possible that other phloroglucinol compounds may be found to give the same result; but the author was unable to obtain the reaction with quercetrin which yields only a non-distinctive red or brown of the kind so frequently given to this kind of test. (6) COMMERCIAL CHRYSAROBIN (PURIFIED GOA POWDER) .-This gives a purplish colour-reaction in Liebermann’s test. On adding a little water and then diluting with alcohol (90 per cent.) the colour changes to green which becomes a characteristic wine-red on adding ammonia. The series of colour changes given make this test one of the most specific for chrysarobin but it should be noted that theJirst colour given may not always be very marked and consequently is liable t o be overlooked USE OF NITRITES OR NITRIC ACID 389 In conclusion the writer desires to thank Dr. Nierenstein who very kindly sent him authentic specimens of several catechins and from whom most of the tanning materials were also obtained. UNIVERSITY COLLEGE OF THE S. WEST, EXETER

ISSN:0003-2654    

DOI:10.1039/AN9255000384

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent.of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent.of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D.G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat.(46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent.of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent.of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent.of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution.Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent.of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000389

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000393

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent.of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent.of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D.G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat.(46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent.of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent.of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent.of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution.Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent.of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent.of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof.(49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent.of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent.of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent.of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000395

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000400

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent.of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent.of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D.G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat.(46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent.of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent.of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000401

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent.of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000404

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent.shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent.of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent.of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent.of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent.of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water.Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat.The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent.of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent.of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat. (46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid).(47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent. of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight.Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent. of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent.of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent.of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D.G. H.142 ABSTRACTS OF CHEMICAL PAPERS milk-solids-not-fat and 3.25 per cent. of milk fat, and in the reductase test (see Section 42) shall require at least 4 hours to decolorise the methylene blue solution. Cream must contain at least 40 per cent. of milk fat.(46) Butter.-Butter shall contain at least 80 per cent. of milk fat, and not more than 16 per cent. of water or 20 grains per lb. boron preservative (calculated as boric acid). (47) Cheese.-Cheese shall contain not less than 50 per cent. of milk fat on the dry substance, and skim-milk cheese not less than 10 per cent. (48) Tea.-Tea shall yield between 4 and 7 per cent. of ash (at least one half of which is water-soluble) and at least 30 per cent.of extract, which shall be determined by boiling 2 grms. of tea in 200 C.C. of distilled water under a reflux condenser for 1 hour, filtering hot, cooling and evaporating an aliquot portion to constant weight. Tea dust shall not yield over 5 per cent. of ash insoluble in water. Cofee.-Coffee shall contain not less than 10 per cent.of fat, and more than 1 per cent. of saccharine matter, and shall yield not more than 6 per cent. of ash, of which not less than 75 per cent. shall be soluble in water. Co$ee essence shall contain not less than 0.5 per cent. of caffeine. Cocoa.-Cocoa paste, mass or slab, is the solid or semi-solid mass pro- duced by grinding cocoa nibs, and shall contain not less than 45 per cent. of cocoa fat. The dry fat-free residue shall not contain more than 19 per cent. of natural cocoa starch, 6-33 per cent. of crude fibre, 8 per cent. of total ash, 5-5 per cent. of insoluble ash, and 0.4 per cent. of ferric oxide. Soluble cocoa or cocoa essence must not exceed a maximum of 3 per cent. of added alkali (as K,CO,) , and prepared cocoa must contain at least 20 per cent. of fat-free cocoa. Chocolate $ash, coatings, +owder and confectioners’ chocolate shall contain at least 16 per cent. of fat-free cocoa. No cocoa husks, weighting substance, paraffin wax, or foreign fat may be added to cocoa or to any preparation thereof. (49) (50) D. G. H.

ISSN:0003-2654    

DOI:10.1039/AN9255000406

出版商:RSC    

年代:1925

数据来源: RSC