摘要:

AbstractA colorimetric method for the determination of protein in wheat and flour is described: its application to the routine analysis of these materials has been studied from several technical and chemical aspects. The method has been found to possess certain economical and practical advantages over the Kjeldahl method, whilst the results obtained show excellent correlation with those obtained using the latter procedure.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740120111

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractExtracts of ox‐muscle were investigated with a view to identifying the reducing substances present which are responsible for the rapid browning of these extracts at room temperature.Sugar phosphates were found to play an important part and the reactions of these phosphates with amino‐acids in extracts and in model systems were followed.The development of colour and flavour in an extract, in a synthetic extract, and in model systems were investigated and found to be a result of the Maillard react

ISSN:0022-5142    

DOI:10.1002/jsfa.2740120112

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractThe aim of the work was to extract and identify ethylenediaminetetra‐acetic acid (EDTA) and 1,2‐diaminocyclohexanetetra‐acetic acid (CDTA) or their iron chelates from plant material. Methods were investigated for concentrating these substances and for separating them from the salts, sugars and coloured material that occur in aqueous plant extracts so that identifications can be made by paper chromatography.A new technique for the quantitative analysis of EDTA and CDTA is described, the principle of which is the sequestering of the metal from highly‐coloured metal complexes.At pH 2 the chelating agents are retained on columns of cation‐exchange resin and can be eluted with dilute ammonia. Before ion‐exchange chromatography any iron present is precipitated with NaOH in the presence of excess calcium ions.The iron chelates are completely adsorbed from aqueous solutions on columns of activated charcoal; salts and sugars are eluted with water and 5% aqueous ethanol, the iron chelates with 25% or 50% ethanol.EDTA and CDTA, or their iron chelates, can be separated by paper chromatography using a 4:1 w/v phenol‐water solvent. The chelating agents are located by staining with nickel dimethylglyoxime and the iron chelates by viewing under ultra‐violet light. When the chelating agents are labelled with14C the positions are found by radio‐assay of the chromatogram in a wind

ISSN:0022-5142    

DOI:10.1002/jsfa.2740120113

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractThe amounts per unit weight of nitrogen, phosphorus, potassium, magnesium, calcium and sodium in individual Cox's Orange Pippin apples from the single tree vary by a factor of two.Replicate random samples of 25 apples from one tree should (19 times out of 20) give means within ±6% of the true mean for nitrogen, phosphorus, potassium and magnesium.The amounts per unit weight of phosphorus, potassium, magnesium and calcium in different regions of an apple vary several‐fold, the gradient being from outer cortex to core.The proportionality previously reported between potassium and magnesium from different treatments and different seasons applies to single apples and to portions of an apple.Magnesium and phosphorus show a very highly significant correlation in portions of apple, and also between apples, which has not been evident between seasons and between treatmen

ISSN:0022-5142    

DOI:10.1002/jsfa.2740120114

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY

摘要:

AbstractThirteen commercial and experimental soya‐bean oil meals were included in practical chick rations either as the only protein supplement (33–35% of the diet) or as 14–23% of the diet together with protein supplements of animal origin, and their nutritional quality was tested in five growth experiments.Growth rate and feed/gain ratio were significantly affected by the nutritive properties of the soya‐bean meals, which depended directly on the degree of processing. Heat treatments, adequate for driving off the solvent according to normal commercial production methods, were insufficient for producing soya‐bean oil meals of maximal nutritional quality. This was obtained only under conditions of heating for a prolonged period after a high level of moisture had been initially obtained.The presence of fishmeal and skim milk powder in the chick rations did not eliminate the importance of adequate processing of soya‐bea

ISSN:0022-5142    

DOI:10.1002/jsfa.2740120115

出版商:John Wiley&Sons, Ltd    

年代:1961

数据来源: WILEY