摘要:

AbstractFour non‐lactating cows, each fitted with a rumen cannula, were given a diet of grass silage, molasses, barley, soya bean meal and a mineral mix (70:14:9:6:1 on a dry matter basis) in eight meals a day. Four experimental treatments, consisting of intraruminal infusions of sodium bicarbonate at 0, 300, 600 and 900 g d−1in a 4×4 Latin square design, were used to study the effects of added bicarbonate on the rumen environment and on the predicted rumen degradability of soya bean meal, rapeseed meal and fishmeal.Mean rumen pH values were 6.26, 6.53, 6.73 and 6.87 for the control and bicarbonate treatments, respectively; corresponding values for the fractional outflow of rumen liquid were 0.129, 0.142, 0.151 and 0.153 h−1(SED 0.01; P>0.05) and for the fractional outflow rates of Cr‐mordanted protein particles 0.035, 0.040, 0.048 and 0.054 h−1(SED 0.001; P<0.01).Sodium bicarbonate had no effect on the disappearance of soya bean meal or rapeseed meal nitrogen from Dacron bags incubated in the rumen, but at the 900 g d−1level there was an increased nitrogen disappearance from fishmeal at all incubation times; disappearances after 24 h were 0.64 and 0.68 (SED 0.025; P<0.05). Using the values for the disappearance of nitrogen and the outflow rates of Cr‐mordanted protein the predicted rumen degradabilities of soya bean meal and rapeseed meal were reduced by about 8% by the 900 g d−1infusion, but for fishmeal there was no change in degradability since the effects of an increased outflow rate were counter‐balanced by an increased rate of loss of nitrogen in the Dacr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420402

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractA highly lignified lignocellulosic substrate, barley straw, was modified by treatment with a variety of chemical and biological reagents. These reagents had specific effects on different components of the cell wall. The residual materials after the treatments were analysed for their composition and degradability by two biological pretreatments, rumen liquor and pepsin/cellulase. The biological pretreatments (cellulase and hemi‐cellulase) gave residues with decreased degradability. Reagents which primarily attack the hemicellulose component gave residues with slightly increased degradabilities. When the treatments primarily hydrolysed the phenolic acid/acetic acid ester bonds, the degradabilities were also slightly increased, but only reagents which primarily attack the core lignin component of the cell wall gave residues with greatly increased degradabililies. Similar results were obtained with both biological systems, but the rumen liquor system was always more efficient than the pepsin/cellulose syste

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420403

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractBalance studies were conducted with intact and caecectomised hens to assess the influence of the caeca on the recovery of intact glucosinolates (IG) in excreta. The hydrolysis of IG in in vitro incubations with gastrointestinal tract contents and with excreta from intact and caecectomised hens was measured to aid in the interpretation of the IG balance data. Decomposition of IG in excreta was shown to result in low recovery of IG in balance trials involving long (22–24 h) collection periods for excreta; however, balance trials with caecectomised hens and in which excreta was collected within 2 h showed high recovery. In vitro incubation studies confirmed the caeca as the major source of the IG hydrolytic activity. Free thiocyanate ion concentration of excreta of intact hens markedly exceeded that of the diet, but hydrolysis of glucosinalbin did not appear to be the major source of the thiocyanate io

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420404

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractStudies on the proteins of five varieties of kodo millet showed that there are hardly any varietal differences. Fractionation of the proteins showed that glutelin is the major storage protein. The amino acid compositions of the protein of the five varities of kodo millet and the individual protein fractions of two varieties were determined. Lysine is the most limiting amino acid followed by methionine and cystine. There is no significant negative correlation between lysine levels and protein content. Sodium dodecylsulphate polyacrylamide gel electrophoresis patterns indicate great similarities in the different varieties.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420405

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe seeds of the five commonly consumedAmaranthusspecies have been analysed for their chemical composition and starch characteristics. A notably high fat, protein and ash content in the seeds of a sample of A. teunifolious as compared with other species has been demonstrated. All the samples analysed had a high oxalate and phytic acid content. The size of the starch granules from all the samples was in the range 08.2.3μm and the circular shape of granules from all the species was strikingly similar.Amaranthuspolygamous and A. gracilis had low amylose starches (111.7 and 97.1 g kg−1, respectively), and A. spinosus and A. teunifolious had appreciable proportions of amylose (166.7 and 245.0 g kg−1, respectiv

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420406

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractChanges in total (1→3), (1→4)‐β‐glucan content were followed during the micro‐malting of nine varieties of barley with a wide range of malting qualities. These changes were related to estimates of endosperm modification based upon staining with Calcofluor. β‐Glucan content declined from an average of 3.54% in the barley to 0.75% in the malt. Pentosan and total starch (including starch‐derived oligosaccharides) levels showed comparatively little change during malting. β‐Glucan composition of the barley was a poor indicator of malting performance. However, the β‐glucan, starch and xylose contents of the malt all showed significant correlations with malt extract. Estimation of malt β‐glucan content gave the best indication of malt quality. Direct determination of β‐glucan may be of more value in assessing malt quality than indirect techniques based upon assessing mod

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420407

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractThe mutagenicity of the basic fractions of fried beef patties, grilled hamburgers and grilled sausages was determined in the Ames test using activation systems (S9‐mix) derived from untreated and Aroclor‐pretreated rats and hamsters, and from rats pretreated with 3‐methylcholanthrene or phenobarbitone. In order to indicate whether the mutagenic activity was due to the presence of thermally generated amino imidazo aza‐arenes of the type previously identified in heated meat products (i.e. 2‐amino‐3‐methylimidazo[4,5‐f]quinoline (IQ), 2‐amino‐3,4‐dimethylimidazo‐[4,5‐f]quinoline (MeIQ) and 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quin‐oxaline), these compounds were assayed under the same conditions. The mutagenicity of the basic fractions of the cooked foods and of the three aza‐arenes varied with the activation system used. The activation patterns of the basic fractions from fried beef and grilled sausages resembled that of IQ, whereas that of grilled hamburgers was more similar to that of MeIQ. Interestingly the total mutagenic activity of fried beef patties was gr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420408

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractTurbid solutions and fine‐stranded gels of myosin from bovine semi‐membranous muscle were investigated by transmission and scanning electron microscopy. Evidence is given that the turbidity was caused by filament formation upon dialysis to pH 5.5 and 0.25MKCl and to pH 4.0 and 0.6 m KCl at 4°C. The filaments formed at pH5.5 and 0.25 m KCl had a backbone with a diameter of c. 25 nm with the myosin heads located close to the filament backbone. The total width of these filaments was c.45nm. The filaments were prepared for electron microscopy by adsorption on various substrates, negative staining, or freeze drying and rotary shadowing. Variations in the preparation technique did not affect the appearance of the filaments. The filaments formed at pH 4.0 and 0.6 m KCl had a more irregular appearance, and the total filament width varied between 20 and 45 nm. Fringes of globular material surrounding the filament backbone were seen but also clusters of myosin molecules protruding further out from the backbone and from the filament ends.Comparison of heat‐treated filaments in dilute solutions with strands of the gel network confirmed that the gel strands originated from filaments formed upon dialysis prior to gelation. Typical features of the network structure were junction zones formed by parallel alignments of filaments in pairs and by end‐to‐side interactions forming so‐called Y‐junctions. At pH5.5 and 0.25 m KCl these interactions resulted in a rather loose and open network structure. At pH 4.0 and 0.6 M KCl the filaments often interacted approximately at right angles, which resulted in a denser network than that observed atpH5.5 and 0.25 m KCl. The efficient network formation at pH 4.0 gave rise to spontaneous gel formation upon dialysis without any heat treatment. Additional heating did not change the character of the network, and no differences could be observed between unheated and heat‐treated gels at low magnifications. At higher magnifications it could be seen that heating resulted in loss of details of the filaments at both pH values and ionic strengths. The shape of the myosin heads was lost, and the heads fused together on the f

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420409

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

摘要:

AbstractReversed‐phase high‐performance liquid chromatography was used to study post‐mortem variation in dephosphorylation of inosine 5′‐monophosphate and accumulation of its breakdown products in turbot (Scophthalmus maximus) muscle during storage at low temperatures. The relative concentrations of these compounds can be used as an index of freshness. Nucleotide decomposition and nucleoside and base accumulation are influenced by the following storage conditions: chilling at 4°Cfor 1 to 15 days; freezing for 15 days of pre‐ or post‐rigor muscle at various temperatures between ‐10 and ‐196°C; and qu

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420410

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740420401

出版商:John Wiley&Sons, Ltd    

年代:1988

数据来源: WILEY