126 THE ANALYST. ANALYSES OF FLOURS AND BREADS. BY J. CARTER BELL, F.C.S. llentl btforcz tlie Society of Public Analysts, o n 4th Jiuae, 1879. SINCE December, 1877, I have been engaged upon the analyses of flour and bread, -with the object of satisfying myself, by actual experiment, as to the quantity of phosphate of alumina contained in those two essential articles of food. Like many other chemists I was under the impression that the quantity of alum calculated from the phosphate of alumina found in a four-pound loaf was very small, but since I have analysed over one hundred samples, my views have been considerably modified.I t is with diffidence I bring tliese analyses forward, as the Institute of Chemistry seems completely to ignore the original work of Public Analysts, and is groping hopelessly in the dark ; whereas, if 6ome guidance were accepted from men who have had practical experience, the Institute might gain some information upon the analysis of food, of which it confesses itself at the present time ignorant.I n the Conference upon Milk no mention was made of the labours of Mi*. Wanklyn, myself and others. In my experiments upon milk, I had 183 cows milked in my presence at various times and seasons ; the milk from the majority of these cow8 was analysed separately, and all information, such as food, age, colour of cow, &c., was obtained, so that accurate data could be registered for fixing a milk standard, which I flatter myself I have obtained, and now decide according to that standard.It may be that this quiet ignoring of work accomplished, may arise from a modest desire of the Institute that men should not labour and the Institute enter into their labours.In the following analyses, which for the above reasons I forward to the Society of Public Analysts, I have been careful to obtain samples of flour and bread of acknowledged purity. Many of the sainples of flour were obtained from Mr.Render, of the Crown Flour Mills, Salford, and of Mr, Moss, of West Gore Street Mill, Sttlford ; they, knowing what I required the samples for, were most careful in supplying them as pure as they could possibly be. My method of analysis was that proposed by Dr. Duprh, and modified by Mr. Wanklyn. Before incinerating flour or bread, I always thoroughly dry the samples, as I find they burn away in a much shorter period, and no unpleasant vapours are evolved.Much has been said and written about the logwooci test and its uncertainty, but according to my experience, if the solution is prepared according to the directions given by JIr, Horslcy, it works admirably. I trtke 16 gfiiumes of freslily-cut logwood, andTHZ ANALYST. 127 digest in cold methylated spirit for about eight liours, with an occasional slialie of tlie solution ; at tlie end of tlie eight hours the clear liquor is poured off.For bread, about 10 grammes of the crumb are taken, and a mixture consisting of 90 C.C. of water, 5 C.C. of the logmoocl solution, mid 5 C.C. of a saturated solution of csrboiiate of ammoiiia is poured over the bread in a porcelain dish.If tlie bread coiltalus alum, a dark lavender blue soon inalres its appearance. The bread is washed and dried ; if the blue lavender colour remains, I always fiiid that alum is present. For flour, Iweigh out 10 grammes, mix mitli 10 C.C. of water, then add 1 C.C. of log1~700cl solution, and 1 C.C. of carbonate of ammonia solution ; if tlie flour is pure, piiilrisli colour is obtained ; wliereas, if alum is preseiit, the pink is changed to lavender, and I have detected alum in flour in so small a quantity as 3 grains to the four-pound loaf.By having a standard solution of alum mid ndciiiig it to flour, it will be at once seen wliether tlie logwoocl solution is fit t o use. I have liad mine nlztde LIP for several months, aiid it is still good.Until I read Dr. Diip8's paper, I liad not paid muel1 attention to the silica in flour and bread ; but I now see that it forms a very important item in the analysis, because whenever I obtained a high silica, I looked for a high pliosphate of alurniiia. In all cases of flow and bread; I have cslcdated the silica and alum in grains to the four-pound loaf. Tlie crowii is tlic trade marl< of the firm; five crowns beiiig the best flour, and made from the centre of tllie grain of the choicest wheats, while the lower crowns are of inferior qiiality.Thus, t'lie price of five crowiis is 48s. a sack, while one crowii is 34s. ; the intermediate ones are between the t v o cstremes. These floiirs vere made from a mixture of English niid Californian wheats. No. 2 C L ' O T V ~ lias a very high phosphate of alumina, eqtialling about 16 grains of alnin to tlie four-pound loaf.I tliought that there must be some mistake ns regards this flour, tvliicli led me to make further csperiinents. The flour The first lot of five flours I obtained from Mr. Render, in 1877. was andysed four times, with the folloming results :- Grains of Silica to 4 lb. loaf. No.1 Silica e l 0 0 . . Phosphate of alumina -021 .. 21 2 ,, -102 .. 9 , -017 .. 214 3 ,, -105 .. 9 I -020 .. 22 4 ,, -109 .. 9 , so84 .. 22; These results do iiot agree so well as could be mishcd, owing, I Grains of Alum to 4 lb. loaf. .. 152 .. 123 .. 15 .. 18 expect, to the mechanical mixture. I cannot believe that this ainouiit of alumina is n coiistitueiit part of tlie grain, but must arise from imperfectly cleaned wheat.Tlie large percentage of silica is an important item to be noticed in the analysis; any chemist using moderate care could not return this flour as adulterated with alum. Five 1iound.s of the flour were made into bread. Tlic analysis of the bread crumb gave :- lfoistnre . . , . . . . . 45.000 per cent. Silica .. .. . . .. -066 ,, Phospliate of iron .. . . . , -007 ,, Phosphate of aluiniiin , , . . -011, OY 11$ grains alum to the 4 lb. loaf. I t is my practice in bread analysis, to deduct 10 grains of ahin from the total quantity calculated from the phosphate of alumina fouiid in a four-pound loaf. So that, on the above bread, when the ten grains are deducted, the quantity left would be128 THE ANALYST.80 small, that takiiig iiotice of tlie high dim, this bread could iiot be retuned as containing alum. Out of the one hundred samples I have examined, this is the only iiistance of a loaf which contaiiis 11 grains of alum. Two other flours-one marked Russian, a,nd the other Ghirklt-gave high alumina, but at the same time high silica : these were coarse flours, such as tt good baker would not like to use, The analyses of these were as follows :- 100 parts contain Bussian.Ghirka. Moisture . . . . . . . . 13.86 . . . . . . 8.280 Ash . . . . . . . . . . *58 . . . . . . -692 Silica . . . . . . . . . . *055 . . . . . . -062 Phosphate of iron . . . . . . *007 . . . . . . -007 Phosphate of slniiiiiin . . . . -01G . . . . . . -01G 23, lbs. of this Russian flour were made into bread ; it made a very coarse browii losf, and the analysis was as follows :- Moisture .. . . . . . . . . 42.700 Silica . . . . . . . . . . . . -034 -Phosphate of iron . . . . . . . . 0006 Phosphate of alumina , , . , . . a010 or 10 grains to 4 lb. loaf. Here, again, the deduction of the 10 grains leaves nothing to return as alum, These I consider extreme cases : for it will be seen by the great number of samples of bread which I have bought from shops in Salford, not one reaches 10 grains of alum to the four-pound loaf.Some of the flours in the following list require a little explanation. No, 1 Crown has a high silica ; this analysis was made in 1877, but while writing this paper I have estimated the silica again, a d the mean of the two gives 0077.No. 2 I have already explained, I have tried to obtain some more of the same kind of flour but have not succeeded. I n June, 1877, I analysed another sample of 2 Crown Flour- Silica . . . . . . . . . . -009 Phosphate of iron . . . . . . . . -003 Phosphate of alumina . . . . . . 0008 In March, 1879, another lot of 2 Crown gave- Silica . . . . . . . . . . -021 Phosphate of iron .. . . . . . . -004 Phosphate of alumina . . . . . . -010 From these, and other samples, I am inclined to believe that the sample of 1877 was an exceptionable one. I have found that fine flours are less likely to contain high silicas a d alnminas mheii they have been prepared by what is called the c 6 high grind process :” by this a central portion called “ extract ” is taken from the wheat, by the millstones being kept further apart than by the old process of grinding; thus leaving a large amount of flour adhering to the bran, which being again re-ground gives a poor flour called ‘‘ bran flour,” which is liable to contain more alumina than the extract flour, in consequence of being subject to a more severe treatment between the stones.extract ” and the bran flour there are several intermediate qualities of semolina flour, from which Some of the choicest flours now in use are produced, Between theTHE ANALYST.129 The American spring wheat lias a liigh silica, -054; this was estimated in 1877. Residue Flour is called in the trade (' inferior re-grounds.'! Brnlc Flow. This is flour that lies closest to tlie skin, wliich lias been removed by second grinding, a d only produced by the high giind process. This is flour drawn from the stones by the drauglit which keeps the stones cool, It is liable to contain a larger quantity of alumina than found in ordinary flour.Within the last few days tlie analysis has been repeated, with the same results. Rxhaiut E'loitr. No. 18.-From a country mill in Cheshire.Nos. 19, 20, 21.-Made in Salford by Mr. Moss, by the old process of grinding. Nos. 26, 27.-Bouglit from bakers, in Salford. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13, 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24, 25, 26 I 27. 28. 29. 30. 31. 32. One Crown Flour . . . . . . . . . . Two ,, ,, . . . . . . . . . . Three . . . . . . . . . . . . . . Four , . . . . . . . . . . . . . Five .. . . . . . . . . . . . . White English Wheat, 1877 . . . . . . Red ,, . . . . . . . . American Spring Wheat . . . . . . . . .. Red Winter Wheat . . . . . . Empress Hungarian . . . . . . . . Residue Flour, from 1, 2, 3 mixture of Crown . . Bran Flour . . . . . . . . . . . . Exhaust Flour . . . . . . . . . . Russian Flour . . . . . . . . . . Egyptian ,, . . . . . . . . . . Ghirka, ,, .. . . . . . . . . Semolina ,, . . . . . . . . . . 9 , 100 parts contain Grains Grains Phos- Phosphate of of phate of Silica to Alumto Silica. of Iron. Aluminn. 41b. loaf. 41b. loaf. Moisture. Ash. 13.02 -625 *077 -0107 418 16& 134 12-62 '604 *lo5 *0056 ,0204 22 16 12.46 -52 .024 -003 *009 5 7 12-08 -488 *012 *003 ,005 2+ 4 11-82 -484 -010 .002 ~004 2 3 13-62 *438 -020 ,004 -010 42 7f 12.62 -492 -056 ,006 *013 112 10 13.06 -380 *014 -002 -007 3 54 11-44 -368 .010 *001 *002 2 14 9.48 *476 ,028 *010 .010 53 7g 8-92 *488 0029 0009 .012 6 9% 11.35 ,610 ,0268 -0058 -011 5& 84 13.86 -680 ,055 ,0072 -0162 ll* l2A 12.98 0700 ,020 *0045 -0059 4% 4& 8.28 *593 ,062 *0067 -0163 13 12* 7.02 ,440 .011 -0008 .0062 22 44 9.84 ,448 ,015 905 -007 6 51- Flour, English a d foreign wheat, 2 English,) 3 foreign; the foreign principally Californian! 2'oo '400 '020 *Ool 'Ool 4;3 9 Straws.made in Salford . . . . . . . . 13.22 -6'72 so10 00021 -0023 2 12 Coarse Flour, or seconds, containing bran . . 13.92 1.44 -052 -0032 *0038 11 44 White Flour, made in Salford . . . . . . 13.02 *680 -023 -0032 *0018 5 14 Peerless Flour, made by Banaman, Sherman and} 13.30 .500 ,ooo25 .ool 2* if.Go., Rochester, U.S. . . . . . . . . Rochester, U.S. . . . . . . . . . . Gilt Edge, made by Chase, Bristol and Bide,} 13.04 ,516 .020 ,00027 .ooo8 4% CalifornianFlour . . . . . . . . . . 12.60 -480 *021 ,0064 *0078 44 6% WhiteEnglish, 1878 . . . . . . . . 14.90 *368 -021 -0035 -0049 4& 32 -0005 W15 1 12.80 -0335 . O M -009 7 7 per cent, Red English, 30 per cent.Califor- 12.80 ,260 *023 00037 -0087 4g 62 Two Crown Flour, total produce of wheat-40 nian White, 30 per cent. Canadian White . . ~- BranFlourfrom Two Crown Mixture . . . . 12.30 -76 .046 -007 -016 9& 124 P. A. Campbell, SanFrancisco . . . . . . 12.200 -300 -016 *003 -004 31 3 J. F., Salem Mills, United States.. . . . . 10,320 -448 -012 901 0004 24 3 Two Crown Flow, less 5 per cent.Bran Flour . . 13.00 -26 ,0214 -004 -0106 44 8$ . . . . 10*000 ,520 -013 ,002 .001 2% 3130 THE ANALYST . The following thirty-two breads were bought from bakers in Sslford. and the crumb of the bread was taken for aiialysis- 1 . 2 . 3 . 4 . 5 . 6 . 7 . 8 . 9 . 10 . 11 . 12 . 13 . 14 . 15 . 16 . 17 . 18 . 19 . 20 . 21 . 22 . 23 . 24 . 25 .26 . 27 . 28 . 29 . 30 . 31 . 32 . Bread .. 3 9 3 9 1) .. 9 9 .. 11 ¶ > .. 9 1 .. 1 ) .. 3 1 7 9 $ 9 .. $ 9 .. .. 1 7 .. .. .. 11 .. .. a 9 .. 91 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . Moisture . 46-10 45-00 45.50 40.30 40.50 46.00 44.50 46.00 46-00 45.50 46.50 46.00 46.00 46.00 46.20 47.50 46.50 49.50 47.50 46.50 47.20 46.50 45-50 46.00 45.30 46.20 44-50 44.00 45-60 44.50 44.00 46-00 Pho sphatc Silica . of Iron . *014 -0010 *033 -0013 -019 *0013 -010 -0013 -012 *0010 -015 *0013 *017 -0016 *014 * 0018 -013 *0010 . 039 . 0029 -014 . 0013 -018 *0010 -037 .0013 ~021 -0026 * 013 . 0032 -019 *0005 . 012 . 0013 . 016 *0018 *021 -0016 0016 -0018 *029 *0018 -0205 -0018 *024 -0018 -015 -0026 -015 -0040 . 019 0032 a019 -0040 . 020 *0026 *012 *0016 a019 *0018 -017 00026 . 025 . 0018 Phosphate of Alunlina . -0030 -0067 *0037 so022 . 0030 -0046 . 0034 SO082 -0040 *0031 -0052 -0050 -0067 *0026 -0028 -0045 -0043 *0032 -0064 -0037 *0042 -0068 -0064 -0066 *0052 ~0044 *0038 .0058 -0044 *0048 *0042 *0058 Grains of Silica to 41b . loaf . 3 7 4 2 ;i :+ 83$ ;2 F 32 32 72 4& 24 34 44 4f 5 3 3 4 4 44 7 The following eight breads were made under my own superintendence from flour which I had analysed. and wkich appear in the table :- 100 parts contain Grains of Grains of Phosphate Phosphate Silica to Alum to Moisture .Silica . of Iron . of Alumiua . 41b . loaf. 41b.loaf. Bread made from One Crown Flour . . . . 45.00 -051 . 001 '003 103 3 Three .. . . . . 4000 *019 00026 -009 .. .. Four 1 9 . . . . 38.00 -016 . 005 *004 34 4 .. 11 Tmo 11 . . . . 45.00 -065 4067 . 011 1; .. l l Five .. 36.50 -013 -0046 -0022 22 t * 9 :$ 9 9 .. .. White Engzsh Whea" .. 36.90 015 -003 so04 3 9 1 91 91 Red ..39.50 0020 *0021 -0053 .. Russian Flour . . . . 42.*70 -034 . 010 -0053 These breads were made by Mr . Render. from samples of flour ground by himself . The bread in most cases was tlhd with logwood. but gave no indications of alum . 4 8 Bread 50 per cent . English Red. 50 per cent.} 42.50 Canadian White . . . . . . . 019 . 0032 . 0082 .. Pure White Canadian . . . . . . 42.50 -021 -0018 -0035 44 34 Canadian Semolina 43.90 -008 00026 -0032 13 32 ... . . . . . 3 9 .. Californian Flour . . . . . . . . 43.50 . 023 . 0072 *0100 4Q 10 .. One Crown Flour . . . . . . . . 46.50 *019 *0035 -0031 4 3 .. Four . . . . . . . . . . 45.00 *008 *0053 *0053 13 54 The following are some instances of pure samples of bread. which when treated with the logwood solution gave a very suspicious blue colour when met. and caused me to think that durn T .Y ~ S present. but after washing and drying the sample there was not the slightest trace of blue colour ; a i d I sliould strougly urge all analysts to dry the .. 50 per cent . English Red. 50 per cent.} 43.00 . 015 . 0026 . oo9 Semolina . . . . . . . .THE ANALYST. 131 samples of bread before giving a decided judgment upon the presence or absence of alum.I t is now my habit to enter in st note-bDok my opinion as regards a sample of bread when treated with tlie logwood solution before taking further steps, to show how easily one uay be deceived by giving a verclict without trying tlie logwood test. 1 had two samples of bread from the County of Chester, a few days since. The logwood tmt was applied as usual.I entered-" The bread has a bluisli colour, and I slioulcl tliiiili there will be about 8 grains of slum to the four-pound loaf," The analyses of the samples were- ;: : 48.1 -008 -002 *006 47.5 *012 -004 ,004 When the bread was clry there was no blue colour. The following are some samples which I have analysed, thinking from the logwood test that they contained alum; if I had waited until the logwood bread was dry, I should then have seen that I had been mistaken, but having begun the analysis I thought it would be interesting to finish.I have arra'nged them in order of tlie silicas. Phosphate Phosphate Grains of Silica, Gi+ains of Alum silica,. of Iron. of Alumina. to 4 lb. loaf. to 4 lb. loaf. *008 .. .. -002 .. .. -005 .... 22 .. ,. 5 *012 .. .. -004 ,. .. *004 .. .. 3& .. ,. 4 ,018 .. .. .003 .. ,. *005 .. .. 5 .. .. 5 0020 .. .. ,004 .. .. -003 . . .. * . .. 3 0027 .. .. -006 .. .. 0010 .. .. 74 .. .. 10 0031 .. .. -004 .. .. *009 .. .. Sg .. .. 0 ,031 .. ., *006 .. .. *010 .. .. 8+ .. .. 10 0031 .. .. -004 .. .. -009 .. .. 8& .. .. 9 *039 .. .. -003 .. .. -008 .. .. 11 .. .. 8 a023 .... *005 .. .. -010 .. ,. ? .. .. 10 B r e d containing alum- 0008 .. .. ,003 .. .. -026 .. ., .. .. 26 -015 .. .. -004 .. .. 4 2 5 .. .. 3 .. .. 25 so16 .. .. *004 .. .. -034 .. .. 4& .. ,. 34 -017 . a -003 * . '037 .. - 6 42 .. .. 37 -020 .. .. *004 .. . . 0040 .. .. 5+ .. .. 40 -020 . , .. -005 .. .. -024 .. .. * . .. 21 -022 .. .. -003 .. .. -026 .. .. ? .. .. 26 .029 .. ..-003 .. .. ,041 .. ,. .. .. 41 *030 .. .. *005 .. .. *037 .. .. :$ .. .. 37 -030 .. .. -005 .. .. -028 .. .. 84 ,, ,. 28 -033 .. .. -004 .. .. -015 .. .. 9a . . .. I5 -037 .. .. -004 .. .. -021 .. .. lob ,. ,. 21 *040 . . . . *005 . . . . *032 . . . . l l a . . . . 32 -041 .. .. ,004 .. .. *015 .. .. 113 .. .. 15 *041 .. .. -008 .. .. -013 .. .. .. 13 ,046 .. .. -003 .. .. ,020 ..:: .. .. 20 I thought it would be interesting to trace the alumina from the wlieat, through tlie various products. I therefore procured some wheat from Mr. Render,' and he prepared the bran, flour, &c., specially for me. Contained in 100 parts Grains of Grains of Alum to Moisture. Ash. Silica. of Iron. of Alumina. 41b. loaf. 41b.loaf. Phosphate Phosphate Silica to Eiiglish Wheat grown ttpon chalk soil * 9.512 1.720 -00 & -013 10 Sharps, 8& ,, One Crown Flour, 26 per cent... 13.20 *500 *008 *003 *007 1Q 5& Four ,, 45 ,, .. .. 13.28 .368 ,011 .002 ,006 2& 45 ,. .. ,, 12.720 2.000 .034 -007 'OX -017 437* 123 12+ Bran, 184 per cent. . . . . . . 12.400 5.640 -206 -046 * The samplc of d i e a t hail been lyiiig i u the iiiiller's office for soiuc days.This J;ill acconiit for the low moisture.132 THE ANALYST. Mr. Penney, on page 80 of the Chcnzical News for this year, states--"It has recently become apparent that the attempt to fix upon a standard must be abandoned." My labours, which have extended over fifteen months, duri11g which time I have examined nearly two liundred samples, lead me to rz more hopeful conclusion, and appear to prove that a s t a d d can be fixed ; and a chemist with common judgment ought to be able to determine whether any excess of alumina is due to adulteration, or to other causes.I t may please the public to know that out of many hundred samples I have only found one case of flour adulterated with alum. Dr. DuprB said he found the logwood often gave a re-action, but the colour dis- appeared when drying; he was in the habit of drying in an air-bath, and that he believed was the original direction when this tesl was first brought prominently forward. Not unfrequently flours might give a suspicion, but dry them and it disappears at once.One point in Mr. Bell's paper struck him as being of value, viz., that the bran in flour should be estimated, and if possible the bran in the bread, because bran contains a large amount of silica and very little alumina. He had just had nine samples of bread to analyse.One gave Che logwood reaction and contained alumina equivalent to 42 grains of alum per 4 1bs.-the silica came to 17 grains per 4 1bs.-so that he reported it to be adulterated with about 24 grains of alum. Dr.Muter said that, with reference to the elucidation of the silicate question by ascertaining the amount of bran present in the flour, he should propose an attempt at the estimation of the cellulose, by a rapid process such as he had tried some years ago on a drug containing only a minute quantity, and which consisted in finding the amount soluble in ammoniacal cupric oxide solution. He prepared some of the re-agent of which he took two equal parts by weight, and placed them side by side ; into one he put the impure cellulose to be estimated, and, after proper maceration, he filtered both fluids through equal weights of a mineral filtering medium, and then evaporated both and dried at the same temperature, and for the same time. The increase in the one residue over the other was supposed to be cellulose; and his impression was that the process promised well, but he intended to try it again on this flour question at his first spme time, Mr. Bell Bad noticed a fact about the logwood test which was quite correct ; namely, that a colour sometimes appears while wet, but disappears on drying. In such cases he had noticed that there was usually sufficient alumina to calculate to about 12 grains a81um per loaf, and an excess of silica such as to prevent its being considered to be really alum. He remembered that in the cellulose process he spoke of, much depended upon the temperature at which the maceration was done, but the exact particulars he had now forgotten.