摘要:

AbstractIncreases in the free fatty acid (FFA) content of oil from oily fish silage, recovered by centrifugation, have been shown to be principally associated with the release of FFA from solid material during liquefaction of the fish. Much of the initial FFA is present in the digestive tract of the fish prior to acidification. Pigmentation of the oil during ensiling is shown to be caused by the release of the acid hydrolysis product of haemoglobin, haemin. A 2% addition of 20 volume hydrogen peroxide has been shown to inhibit oil pigmentation and to reduce the FFA content in the recovered oil. Peroxide values of the oil, reduced by this treatment, can be further reduced by the addition of an oil‐soluble antioxidant to the silag

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320602

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractCollagen exists in at least five genetically distinct forms and the relative abundance of these is determined by the type and age of the tissue. Methods are presented for the detection and estimation of these collagens based on appropriate chemical, physical, histochemical and immunological techniques. The specific difficulties in providing accurate quantitative data for collagen in meat and meat products'are discussed.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320603

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractWinter wheat was grown in pots receiving 0 (K0), 60 (K1) and 120 (K2) mg K 100 g−1soil to investigate the effect of potassium (K) supply on the following yield components: number of ears, number of grains per ear and single grain weight. Mature grain yield increased from 34.5 g per pot atK0to 81 g atK1and 89.9 g per pot atK2. Straw yield increased from 35.4 (K0) to 123.2 g per pot (K2), reflecting an increase in leaf area and photosynthesis. K fertiliser lengthened the period of grain filling by 3‐4 weeks both by advancing anthesis and delaying senescence. The longer grain filling period fed by more abundant assimilates resulted in single grain weights of about 40 mg in central and lower spikelets and as much as 30 mg in the apical spikel

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320604

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractIncreasing the potassium (K) supply to wheat plants grown in pots extended the period of grain filling and increased the rate of grain growth, thus increasing the single grain weight. In all K treatments abscisic acid (ABA) content in the grain reached a maximum and this occurred when the growth rate of the grain declined and full ripening commenced. Increasing the K supply delayed the occurrence of the ABA maximum and reduced its absolute value. It seems that an extension of the grain filling period by better K nutrition might not only be due to a longer production of assimilates, but also due to a retarded and lower production of ABA in the grain. This result is supported by the finding that withholding of water supply for 1‐week periods during grain development increased ABA content in the grain and reduced single grain weigh

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320605

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractFunctional properties of sesame flour and protein isolates have been compared with those of some commercial soya products. The sesame products showed better fat absorption, poorer water absorption and overall lower bulk densities than soya products. Emulsifying activities and stabilities were generally lower than soya products. Destabilisation of the emulsion in the presence of NaCl was noted. Sesame products showed better foam expansion, and comparable foam stability and strength to corresponding soya products. Addition of sugar to sesame whips reduced foam expansion and increased foam stability. Acid, neutral and alkaline sesame whips showed distinct whipping properties depending on the product used. Sesame whips resembling those of egg‐white could be obtained. The sesame isolate prepared by alkaline extraction was superior to that prepared by salt extraction in terms of their pH‐solubility profi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320606

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractNitrogen extractability from sesame flour in water is greatest using a flour: solvent ratio of 1:40 and an extraction time of 15 min. At pH 4.0‐6.5,pH 4.0. The two sesame protein isolates produced were bland‐tasting, light‐coloured and contained approximately 95% protein. The alkali isolate (extracted in water at pH 10.0 and precipitated at pH 4.0) was readily solubilised and showed a good protein recovery (60%). The salt isolate (extracted in 1M NaCl at pH 6.0 and precipitated at pH 4.0) was less soluble and showed a lower protein recovery (50%). The sesame products were extracted sequentially using various solvents. Sesame flour proteins were mainly salt‐soluble (67%), alkali isolate proteins mainly water‐soluble (41%) and alkali‐soluble (41%), and salt isolate proteins mainly alkali‐soluble (35%). The amino acid composition of the sesame products is described. Oil‐expelled cake showed poor nitrogen extractability (53% at pH 11.0 in water) and was, therefore, a poor source for protein i

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320607

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe method of Hoare and Koshland for the estimation of free carboxyl groups in proteins has been scaled down and applied to wheat proteins. With standard proteins, provided the carboxyl groups were not inaccessible (as in lysozyme), the error was as large as 19%. This level of error is acceptable for estimating by difference amide contents when these are high, as in gluten proteins, because the error is greatly reduced by the molar ratio of side‐chain CONH2:COOH—a ‚leverage’︁ effect. About 95% of the side‐chain COOH groups appear to be amidated in the prolamins and about 50% in the albumins. The proportion of Glx + Asx in the amide form seems to decrease slightly as the electrophoretic mobility of a prolamin increases. The errors in calculating the numbers of positive and negative charges that a protein bears at pH 8.9 become serious when superimposed on the net charge, which is the small difference between these numbers. The net charge at pH 8.9, therefore, could not be obtained accurately by calculation. The polarity of the net charge can be determined by electrophoresis using a marker for electr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320608

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractSamples of whole and manually degermed Atou wheat were milled on a micro‐mill to give straight‐run flour, coarse offal, fine offal, finished bran and bran finisher flour. The non‐starch lipids in these products were compared with non‐starch lipids in the aleurone‐free starchy endosperm, and with lipids in the germ and aleurone of the original wheat. About half of the triglyceride in flour was derived from the germ; no glycolipids or phospholipids were derived from germ, and no lipids of any kind were derived from the aleurone. Non‐starch lipids in the aleurone‐free endosperm of a mixed English soft wheat grist were then compared with the non‐starch lipids in 11 flour streams from a commercial mill. All flours had much more triglyceride than the endosperm. In flours from the reduction system there were significant correlations between flour colour grade, sterylester, triglyceride, diglyceride, free fatty acid and diacylphospholipids, but none between ash or protein and colour or any class of lipid. Analysis of the principal components of variation in a simplified matrix describing all 11 flours placed triglyceride, diglyceride, free fatty acid, and diacylphospholipids close together in one group, and all glycolipids andN‐acylphospholipids in a separate unrelated group. Sterylester and colour were loosely associated with the first group but could also be regarded as part of a third loose group with ash and protein. The results are interpreted in terms of lipid distribution within the wheat kernel, and their significance in milling an

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320609

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractAcid‐soluble proteins isolated from three types ofPhaseolusbeans (white kidney beans, navy beans and lima beans) were found to contain phytic acid. The amount of phytic acid complexed by the proteins was unaffected by the phytic acid content of the bean extracts from which the proteins were isolated but depended on the number of positively charged basic groups which were available for reaction with the phytate anion. It was found that the Neuberg formula for phytic acid (C6H24O27P6) represents more accurately the molecular formula of phytic acid associated with the isolated proteins, than does the Anderson formula (C6H18O24P6

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320610

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe interconversion of short‐chain aliphatic alcohols, aldehydes and esters by apple fruit has been studied by gas‐liquid chromatographic analysis of the products when substrates (mainly alcohols) were supplied as vapours to fruit slices at 20°C, and to whole fruit during storage at 3°C. In preliminary experiments with fruit from various sources after different periods of storage, cortical tissue slices formed corresponding aldehydes and acetate esters from alcohols; esterification was more rapid with higher alcohols. Esterification by peel tissue slices was more rapid initially but quickly declined. Metabolism was further investigated with a batch of apples during storage under different conditions. Both cortex and peel tissue were capable of acetylating butanol and 2‐methyl propanol at all stages of maturity, from the pre‐climacteric state at normal harvest time, when endogenous ester levels were low, through 58 days ripening at 12°C. The tissues showed constant hydrolytic activity towards butyl acetate throughout this period. Whole apples in air and 2% O2at 3°C took up ethanol but formed little ethyl acetate and retained very little free ethanol. In both atmospheres whole apples metabolised approximately 40% of added hexanol to hexyl acetate and up to 8% to hexanal. The low levels of esters in apples from low oxygen atmospheres (and the absence of esters in unripe apples) are, therefore, a consequence of low rates of alcoho

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320611

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY