摘要:

AbstractThe nature of endogenous enzymes in the alimentary tract of cattle is examined and their functions in digestive processes discussed. The main digestive enzymes in cattle are salivary and pancreatic lipase, rennin, pepsin, trypsin, lactase and amylase. Maltase and isomaltase, celliobiase, trehalase, elastase and carboxypeptidase are also present. There is no evidence that cattle secrete sucrase. Most of the enzymes secreted by the gut of cattle are present at birth, although peak activities are not always reached until animals reach 2‐3 weeks of age. These activities often persist through to maturity and are generally unaffected by rumen development. The amounts of enzymes secreted are affected by several factors including the nature of the diet, the method of feeding and age. There is also appreciable variation in the secretion of individual enzymes between animals of similar age and receiving the same die

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320202

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractFish viscera silage has been prepared from cod (Gadus morhua) and saithe (Pollachius virens) by mincing the viscera and adding a mixture of formic and propionic acids [1:1 (w/v)] to a final concentration of 1.5% (w/v). Feeding experiments were performed with rats using: (a) freshly prepared silage; (b) fish viscera silage stored for up to 4 days at 30°C; and (c) de‐oiled silage prepared after autolysis and subsequent storage for up to 60 days at 15°C. The nutritional value of the silage has been improved by storage and lipid removal, giving an increase of net protein utilisation (NPU) from below 60% for freshly prepared silage to 70% or above after lipid removal. This increase of NPU can be attributed mainly to an increase in the level of lys

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320203

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe effect of factory processing and commercial end‐cooking on the protein quality of a popular snack food product made with meat, soya, vegetables and cereals (annual production = 10 000 t) was investigated. No change could be detected in either the content of fluorodinitrobenzene‐reactive lysine or the total levels of other amino acids as determined by ion‐exchange chromatog

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320204

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe composition of four different commercial stearoyl lactylate samples has been determined by methylation followed by gas‐liquid chromatography. Components present included lactic, palmitic, stearic, palmitoyl lactic and stearoyl lactic acids. When the samples were used in baking bread their components became bound to starch but could be recovered almost quantitatively after treatment with α‐amylase, showing that they remained unchanged during ba

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320205

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractPreliminary experiments have been carried out to determine the uptake of lead from both hard and soft waters used in the preparation of food and beverages. Lead concentrations in water for the range of 0.05‐0.5 mg litre−1were used to prepare composite groups representing root vegetables, other vegetables and beverages whose composition reflected per capita consumption of these foods in the UK. The uptake of lead from water was highest for the composite group of other vegetables which comprises 70% by weight of green vegetables. For each of the composite groups and the particular water samples used there was little relative difference in uptake whether foods were prepared in hard or soft water. Calculations of the contribution made by lead in water used for preparation of foods and beverages to the total dietary lead intake indicates that at levels of lead of 0.02 mg litre−1, the contribution is about 10% but this can rise to about 40% as lead levels in the water approach 0.1 mg li

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320206

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe effect of various processing regimes on the pectic substances and the final texture of canned mung bean shoots has been studied. A blanching temperature of 75°C for 30 s was optimal in activating the native pectinesterase of the shoots and a holding temperature of 55°C for an optimal 30 min led to maximal deesterification of pectin. This treatment resulted in a canned product that was superior to a sample blanched at 100°C.; the addition of calcium ions did not improve the produ

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320207

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractGrain sorghums containing 1.3, 0.7 and 0.5% tannins were treated with unrefined Magadi soda (37.5 g litre−1) for 3 days at 25°C and evaluated in a bioassay with male weanling rats. The alkaline treatment of the samples containing 1.3 and 0.7% tannins was found to significantly increase the digestibility of crude protein, crude carbohydrates and energy and to improve the biological value (BV) of the protein. Such an effect was not found for the third sorghum cultivar (0.5% tannin

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320208

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractThe ratios of the logarithms of reciprocals of flavour (combined odour/taste) or odour, thresholds in aqueous and oil media can be significantly linearly related to the octanol/water partition coefficients (as logP) of the compounds considered. The use of this lipophilicity parameter to relate thresholds determined in different media may allow the estimation of thresholds in oil media, or oil‐based food products, from the thresholds in wate

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320209

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractA procedure is described whereby the proportion of hexose: pentose in solution may be determined spectrophotometrically. The method uses the phenol‐sulphuric acid reaction and a previously unreported ultraviolet adsorption band at 312‐325 nm in the reacted solutions. The λmaxof this band increases with, and is linearly related to, the ratio of hexose to total sugars in the mixture, in the range 10‐80%

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320210

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY

摘要:

AbstractClassical immunoanalytical techniques are based on native antigens and their precipitation with specific antibodies: they are not very appropriate for the investigation of processed denatured mixtures. This report describes an immunoassay based on the more recent but well‐established enzyme‐linked immunosorbent assay (ELISA) procedure, which in this case is specific for soya proteins that have been solubilised in urea and then ‚renatured’︁ by removing or diluting the denaturant. Levels of soya protein 100 g−1total protein (nominally 100%) were determined with 34 commercial soya products, using a standard reference antigen. Normal expected levels were observed with flours (average 107%) and isolates (108%), while results with concentrates (82%) and texturates (79%) were somewhat lower. Some specialised products gave little or no response, presumably because they are hydrolysed. Meat, milk, egg, wheat and field bean proteins displayed negligible interference. These preliminary results suggest that the ELISA procedure will provide a convenient general method for the qualitative characterisation and quantitative estimation of individual proteins in food products even after severe processing; it seems more attractive than many other methods reported. Immunoassay is capable of large numbers of inexpensive but sophisticated determinations of specific food components. The food analyst should regard ELISA (for the determination in situ of specific antigens in mixtures) as a powerful technique complementary to classical chromatographic and electrophoretic methods which depend on separation before de

ISSN:0022-5142    

DOI:10.1002/jsfa.2740320211

出版商:John Wiley&Sons, Ltd    

年代:1981

数据来源: WILEY