摘要:

AbstractThe total collection method for determining digestibility has been compared with a ratio method that uses as a marker the absorption at wavelength 406 mμ of plant chromogens extracted from the food and faeces.Results showed that when dried grass was fed to sheep the chromogen method gave low results when extracts were read at 406 mμ, and substantially correct results when read at 416 mμ. However, owing to the instability of the plant pigments involved, the plant chromogen method should be applied extensively only after comparative trials have shown that results for digestibilities agree with those found by reliable collection methods.Estimates of the major fat‐soluble plant pigments entering and leaving the alimentary tract showed that there were losses in all pigments during passage down the tract, but whereas losses of up to only 18% occurred in the carotenoids, losses of up to 62% were noted in the total fat‐soluble tetrapyrroles and up to 87% in chlorophylls. The losses varied greatly from sheep to

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050501

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractThe influence of variation in chain length on the reactions between fleece and cationic wetting agents has been studied, with particular reference to octadecyl‐, cetyl‐, tetradecyl‐and dodecyl‐pyridinium chlorides. Reactions with cetyltrimethylammonium chloride closely resemble those with cetylpyridinium chloride. The inactivation of the wetting agents, and change in weight of the fleece samples, have been determined over ranges of concentration, and the two properties correspond closely in all instances. With octadecyl and cetyl compounds considerable inactivation occurs, but with the tetradecyl and dodecyl compounds the interfacial activity of the wetting agent is enhanced; this is attributed to the increase in the solubility of the long‐chain cation‐suint anion complex with decrease in cation chain‐length. At C14and below, the flocculation of suspended matter, which is typical of the longer chains, does not occur. All the curves may be interpreted on the basis of the α, β and γ mechanisms discussed in earlier Parts. The effect of addition of sodium chloride on reactions with cetylpyridinium chloride is considered. Dodecyl‐ and tetradecyl‐pyridinium compounds have been used to compare the properties of the various halides. The change in properties produced by one step in the series Cl‐→ Br‐→ I‐ is approximately equivalent to an increase of two carbon at

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050502

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractThe non‐volatile organic acids are extracted from grass and separated from amino‐acids, sugars, etc., by ion‐exchange chromatography. The acid‐containing fractions displaced from the anion‐exchange columns are further separated by partition chromatography on buffered silica gel.One of the acids present is proved to be quinic acid. By means of filter‐paper chromatography, the presence of succinic, malic, malonic, and citric acids is indicated, thus confirming earlier work. Chlorogenic acid, not previously reported in grass, was also shown to be present. At least two other acids, whose identities are not established, are present, one of which appears to be allied constitutionally to

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050503

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractSamples of ‘collagen’ have been prepared from tendon dissected from shin of beef and found to have a maximum hydroxyproline content of 13.2%, giving a factor of 7.57 for converting hydroxyproline into ‘collagen’. A comparison has been made of the results obtained for the ‘collagen’ content of freeze‐dried tendon preparations (a) by the hydroxyproline method and (b) by the modification of the Lowry, Gilligan&Katersky method previou

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050504

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractMature, stored McIntosh apples exposed for 18 hours in darkness to14CO2were found to incorporate14C in the malic acid, and in the aspartic and glutamic acids, α‐alanine and serine of the nitrogenous fractions, indicating the operation of a system of the ‘malic enzyme

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050505

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractThe McIntosh apple in storage was found to produce malic acid by fixation of carbon dioxide at a rate of about half of the net daily acid loss. The contribution of this reaction to the production of amino‐acids and protein was also quantitatively significant. The fixation activity rose to a high level at the time of harvest and continued to be high throughout the storage period. The rate of uptake of carbon dioxide increased with rising concentration of carbon dioxide in the external atmospher

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050506

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractA method is described by which chlorogenic acid and cyanidin‐3‐monoglucoside are isolated from the liquid portion of canned Victoria plums, so that they may be used in studies on the rate of corrosion of cans of fruit. In the first stage, these substances are separated from all other constituents by adsorption on activated alumina, followed by elution with malic acid solution. In the second stage they are isolated from each other by partition chromatography on a column of cellulose powder. Paper chromatography and absorption spectrophotometry were the main techniques used for the identification of these substances. It appears that the spectrophotometric characteristics of liquors from canned Victoria plums are due mainly to the anthocyanin in the visible region and to chlorogenic acid in the ultra‐violet region. The presence of quinic acid in canned plums has also been demonst

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050507

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractThe component acids present in the fat of the secretory tissue of the udders of a lactating and a non‐lactating cow were determined. The fat of the lactating gland contained about half as much of the lower saturated acids (butyric‐capric) as a typical milk‐fat, with a compensating increase in the proportions of stearic and palmitic acid; all the minor un‐saturated acids of milk fat were detected. Although the fat of the non‐lactating gland contained small amounts of the minor saturated and unsaturated acids characteristic of milk fat, it differed from lactating‐gland fat and also from bovine depot‐fat in the relative amounts of the major component acids; palmitic acid comprised more than 40% of the total acid

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050508

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY

摘要:

AbstractBenzene hexachloride may be determined by hydrolysing it to trichlorobenzene, nitrating to trichlorodinitrobenzene and converting this into chlorodinitroresorcinol by hydrolysis with aqueous caustic soda. Under these conditions the main colour‐producing compound is 6‐chloro‐2: 4‐dinitroresorcinol, but 2‐chloro‐4: 6‐dinitroresorcinol and 5‐chloro‐2: 4‐dinitroresorcinol may also contribute to the colour. Benzene hexachloride is separated from fats in insect tissues by percolating through a column packed with kieselguhr and a mixture of carbon tetr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740050509

出版商:John Wiley&Sons, Ltd    

年代:1954

数据来源: WILEY