摘要:

AbstractNew methods are described for the extraction, chromatographic separation and spectro‐photometric identification and estimation of chlorophyll‐a, chlorophyll‐b, phaeophytin‐a, phaeophytin‐b, carotene and xanthophyll in hay. The most suitable solvent for extraction was 85% acetone. The chlorophylls were separated chromatographically from the phaeophytins, carotene and xanthophyll on a sucrose‐sodium sulphate mixture. The chlorophyll‐aand chlorophyll‐bwere estimated simultaneously in the green solution, and phaeophytin‐aand phaeophytin‐bwere estimated simultaneously in the yellow solution, by spectrophotometry. Carotene and, subsequently, xanthophyll were separated chromato‐graphically from the yellow solution on magnesium oxide, and were

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050101

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractPart I. The historical development of the use of glycerinated fats in baking is traced and some essential differences between American and British practice are discussed. Glycerinated fat comprises mixtures of mono‐, di‐ and tri‐esters; it is commonly but incorrectly called ‘glyceryl monostearate’ and the commercial material in this country, known as GMS, usually contains about 30‐40% of glyceryl monostearate or about 20% of glyceryl mono‐oleate. The effect of GMS products of varying composition on selected properties of bread, sponges and Madeira cakes is described.Specifications for the most suitable types of GMS for use in these products are discussed and the effect that various flour improvers have on the quantities of GMS showing optimum improving effect is described.Various theories that have been propounded to explain the mechanism of the action of fats, oils and GMS as crumb‐softening and anti‐staling agents are critically examined; the view is put forward that greater attention should be paid to the distribution of labile water between the coagulated gluten network and starch gel which comprise the system referred to as bread.Part II. The effect of flour oils in bread making and the influence these substances have on the improving action of the glycerinated fats are discussed. Experiments are described which indicate the presence of monoglycerides in (a) oils extracted from 81%‐extraction flour treated in various ways, (b) oils extracted from bread baked from the severally treated flours and by the aeration process and (c) fats normally used in baking and breads containing these fats. The periodic acid method of estimating monoglycerides in fatty materials is critically examined. The presence of small quantities of monoglycerides in certain of the above materials has been established by applying countercurrent extraction methods and by preparing the 2 : 4‐dinitrophenylhydrazine derivatives of the reaction products in the chloroform layer after periodic acid assay, and by applying other methods of characterization. The influence the various findings have on the pharmacological considerations involved in the inclusion of glycerinated fats (GMS) in baked products is discussed, and in particular the relationship of this information to the concept of ‘hundredfold’ acceptability advocated by Frazer as one of the main criteria in assessing the absence of risk in the use of food additives. As there is also no direct indication of cumulation of glyceryl monostearate in the body, or of any significant nutritional defect caused by the use of GMS in the manner recommended by the authors, it is concluded that the use of glycerinated fats, within reasonable limits, in baked goods involves no ris

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050102

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractA survey has been made of a selection of the lactic acid bacteria occurring in 12 samples of yeast and 9 samples of beer from British breweries. Strains of 8 known species were identified and these includedLactobacillus buchneri, Lb. bifidus, Lb. leichmanii, Lb. plantarumandStreptococcus cremoris, none of which has hitherto been detected in beer. In addition, three rod‐shaped organisms which were isolated proved to be the type cultures of three new species ofLactobacillus.Five cocci which were isolated were found to be related toPediococcus damnosusvar.salicinaceusMees and have been classified as strains of this species. These organisms had very small cells, those ofPed. damnosusvar.salicinaceusitself being relatively much greater in diamete

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050103

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractSelective inhibition of the root growth of germinating seeds is shown by compounds in which a benzene or naphthalene ring is linked in theortho‐position to benzoic acid by CO, CH2, NH or CO‐NH. Rape is usually more susceptible than wheat. The effect of substitution in the benzene ring and of esterification has been examined. 2‐(4‐Phenyl‐benzoyl)benzoic acid andN‐α‐naphthylphthalamic acid were found to be the most active compounds.Some compounds of these classes abolish the normal geotropic responses of rape and rye‐grass roots at concentrations below those at which there is marked inhibition of root growth. High activity was found particularly in the benzoylbenzoic acid and phthalamic acid series. Examination of a few of the compounds reveals that they also affect the phototropic response of shoots of ra

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050104

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractThe root growth of germinating seeds of rape and wheat is markedly reduced when the seeds are grown in the presence of certain aromatic nitro‐compounds. No correlation is apparent between the toxicity and the chemical reactivity, but within comparable groups of compounds water‐solubility appears to be a limiting factor governing toxicity. Methylation of nitrophenols modifies their toxicity but does not destroy it.Arynitramines of the formula Ar‐NH‐NO2are selective inhibitors of the root growth of rape as compared with wheat. The activity is believed to be associated with the acidic nature of the nitramine group and is affected by the nature of the substituents in the benzene ring. The arylnitramines inhibit the geotropic response of roots of rape and ryegrass, and in four out of seven compounds examined the phototropic response of shoots of rape and rye‐grass was also

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050105

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractGeotropic and phototropic responses of seedlings of rape, wheat and rye‐grass are inhibited by 9‐fluorenol‐9‐carboxylic acid and certain of its substituted derivatives. The antitropic effect of these and other acidic aromatic substances is discussed, and it is suggested that they may act through a competitive interference with the lateral transport of β‐indolyla

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050106

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractA study of the analytical results obtained with 1244 samples of silage, examined for advisory purposes during four seasons, has shown interesting relationships between dry matter, crude protein and pH values, and the influence of summer rainfall on these properties. A dry season tends to give a large proportion of samples that have a high dry‐matter content and a low protein content and pH, whereas the converse holds good for a wet season. The results indicate that the best conservation is secured with herbage containing more than 20% of dry matte

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050107

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractSoft wheat, which is considered to be easily susceptible to insect damage during storage, was subjected to infestation by three species of insects, namelyCalandra oryzaeL. (weevils),Trogoderma granariaE. (khapra beetles) andEphestia cautellaW. (almond moth), and the changes brought about by them are reported. The results suggest that, although weevils cause heavy reduction in the weight of the grain, the moth, which feeds only on the germ portion, considerably reduces the grain's viability. The results of an investigation on the degree of unhygienic conditions brought about in the grains by the addition of impurities and body fragments of the insects have been presented. An increase in the acidity of fat, and a decrease in the thiamine content due to insect damage, were both appreciable, but the effect on other constituents of the grain, such as total nitrogen and reducing sugars, was not significant.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050108

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

Abstract1. Changes in the pH and total soluble nitrogen of composts from waste materials have been examined during decomposition for periods up to two years. Losses of nitrogen dry matter and organic matter after 14‐16 weeks were also determined.2. The rate of decomposition, based on the level of soluble nitrogen, in composts from straw and sewage sludge, increased as the initial nitrogen content increased from 1‐10 to 1‐97% above 1‐97% there was no increase in rate of decomposition and losses of nitrogen became excessive.3. Nearly all the soluble nitrogen in mature composts was present as nitrate; the pH of the mature composts varied approximately inversely as the nitrate content.4. Supplementary aeration slightly decreased the level of soluble nitrogen in mature composts and considerably increased losses of nitrogen in 14‐10 weeks. Aeration had little effect on losses of dry matter.5. The soluble nitrogen in mature composts from straw and ammonium sulphate was much greater than in composts from straw and sludge prepared with the same initial nitrogen content.6. The optimum conditions for preparing composts from straw and sludge in small cells are discussed, and the importance of the level of nitrogen, minimal aeration, duration of storage period and the influence of soluble nitrogen in the starting materials are e

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050109

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY