ISSN:0022-5142    

DOI:10.1002/jsfa.2740010802

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractThe component acids of tobacco‐seed oils from plants grown in India, Turkey, Rhodesia and England have been studied: the linoleic acid content varied from 69% (Indian) to 79% (English). The glycerides of the Indian oil were studied and shown to include about 74% of dilinoleo glycerides and 20% of trilinolein. This composition indicates the suitability of the oil as a non‐yellowing oil for paints, alkyd resins, etc., and also shows that tobacco‐seed oils follow the usual pattern of seed‐fat glyceride structure. All the oils studied are thus very suitable for the paint industry (this finding has been confirmed by practical usage in the case of Indian oil), but earlier records suggest that, as in sunflower and some other species, the proportions of linoleic and oleic acid may vary over a much wider range.In view of this variability and of the fact that any oil with a linoleic content of more than about 67% is well suited for drying purposes, the technical designation of oils with linoleic contents of 67% or higher from any of these sources as ‘linoleic‐rich (tobacco) seed oil,’ ‘linoleic‐rich (sunflower) seed oil,’

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010803

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractThe polysaccharidases occurring in enzyme preparations from micro‐fungi, and used in the commercial processing of fruit products, have been examined. It has been shown that the majority of the preparations and cultures of micro‐fungi examined produced enzymes capable of degrading polygalacturonic acid, araban, galactan, xylan, etc. The occurrence in fruits of a mixture of polysaccharides and the presence of the appropriate hydrolases in the enzyme preparations raises certain difficulties in the standardization of these preparations for technological use. In addition, the estimation of the glycosidic hydrolysis of pectin produced by such preparations will consist of the total hydrolysis of polygalacturonic acid, araban and galactan; the assay of polygalacturonase activity by estimation of glycosidic hydrolysis may consequently be inaccurate.The simultaneous degradation of these three polysaccharides in relation to glycosidic hydrolysis, the secondary change in colloidal properties and the structure of pectin, is discussed. Evidence is presented suggesting that the enzymic hydrolysis of pectic acid occurs in two stages, which may be due to separate enzyme actions : the hydrolysis of araban and galactan, and the hydrolysis of polygalacturonic acid. The use of enzymes as analytical tools in the examination of pectin is indicated, and emphasis is laid on the desirability of preparations having a single enzyme activ

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010804

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractThe susceptibility of potato tubers to methyl bromide vapour has been measured by two criteria of damage: the loss of tubers rejected before setting and the reduction of yield per viable tuber. Varietal differences are more clearly shown by the latter criterion, as expected, and less clearly by the former. The damage caused by raising the dosage above a critical level has on the contrary much less influence on the yield per viable tuber than on the loss by rotting in storage. This critical level fluctuates widely, probably seasonally. Tubers fumigated in the autumn are enabled to reverse much of the phytotoxic action of the fumigant and losses are much less severe than if the fumigation takes place in the spring immediately before planting.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010805

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractFactors that may affect the relation of fixation to availability are briefly reviewed. A preliminary assessment of this relationship for superphosphate added to some typical acid soils in N.E. Scotland is made from solubility data on the rate of fixation, the effect of time of application, and the residual value of phopsphate dressings as measured by field and pot experiments.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010806

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractA quantitative study of the saponifiable and unsaponifiable fractions of three samples of South African Pilchard oil and of one sample of maasbanker oil has been made.Differences in the iodine value of the three pilchard oils studied resxulted chiefly from differences in the mean unsaturation of the various homologous groups of fatty acids, the relative proportions of the different groups differing c comparatively little in oils of high and low iodine value. In the oil from the very lean fish the percentage of c22Acids was increased at the expense of the plamitc and c18unsturated acids, an observation which supports Lovern's view that in fasting fish the acids of lower molecular weight are preferentially utilized leading to an accumulation of acids of high molecular weight.Maasbanker iol differed from pilchard oil in that the percentage of C20unsaturated acids was lower and the percentage of C22unsturated acids was highere than in pilchard oil. A more striking difference was the lower degree of unsturation of both the C20and C22acids in the maasbanker oil; this was reflected in its very much lower iodine value.Cholesterol was the chief constituent of the unsaponifiable fraction of both pilchard and maasbanker oil. Other components of the unsaponifiable fractions of both oils were α‐glyceryl ethers, saturated and unsaturated hydrocarbons, fatty alcohols and vitamin A. Evidence was obtained that a C22unsturated fatty alcohol was present in the unsaponifiable faction of maasbanker o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010807

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

摘要:

AbstractFurther comparisons of domestic methods of preserving fruits have been made. The ascorbic acid retained in freshly‐made jam from the three kinds of fruit was greatest in blackcurrant (70%), next in gooseberry (66%) and least in strawberry (55%), and after storage for one year the amounts were 30%, 28% and 17% respectively. The absolute values for ascorbic acid after one year's storage were approximately 6 mg./100 g. both for strawberry and gooseberry jams and 25 mg./100 g. for blackcurrant jam. The loss of this vitamin in making blackcurrant jelly varied considerably with the extraction methods used but was greater than in making jam.The ascorbic acid contents, before and after cooking, of three kinds of fruit preserved with sodium metabisulphite were compared with those of corresponding heat‐processed fruits. The heat processed blackcurrants and gooseberries retained more of this vitamin than the sulphited fruit; the palatability of the heat processed products was greater for all three fruits.Plastic covers for bottled fruit compared very unfavourably with glass or metal covers for conserving ascorbic acid during storage, but plastic rings were as good in this respect as rubber rings when used with metal or glass cov

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010808

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740010801

出版商:John Wiley&Sons, Ltd    

年代:1950

数据来源: WILEY