摘要:

AbstractThe composition of oat husk has been determined in (i) 11 diverse oat genotypes, (ii) current high‐yielding spring and winter varieties from trials in various regions of Britain, and (iii) samples obtained from two British oat mills. Husks were comprised mainly of cell wall (>83%) with about equal quantities of cellulose and hemicellulose (∼30‐35%). Lignin and ash contents were 2–10% and 3.5–9% respectively. Protein and oil contents were low (1.6–5% and 1–2.2%) and only a proportion of the protein (40–60%) and total oil (5–30%) were of apparent nutritional significance. Starch and water‐soluble carbohydrates were very low (<2% and<1%). Pepsin‐cellulase digestibility was low (7–14%) and it was negatively correlated with lignin content in the 11 genotypes. There were significant genetic differences in composition within both the 11 genotypes and the trial varieties; however, the range was small and there were significant differences due to location among the trial varieties. Husk, which was hand‐separated from oat mill samples, was generally inferior in quality to the genotypes and varieties. However, due to groat contamination, industrially separated samples from the oat mills were similar in composition to those from other sources. It is confirmed that oat husk is a poor quality feedstuff and the most significant improvement in grain quality could be made by breeding

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340502

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA microbiological assay usingLactobacillus plantarumwas used to determine the levels of pantothenic acid (PA) in food and digesta samples from sheep fitted with duodenal and ileal re‐entrant cannulas, given a variety of diets. ACP‐bound PA was not measured. With most of the diets studied there was an increase in ‘total’ PA and CoA‐bound PA before the small intestine. Both the increase in CoA‐bound PA prior to the duodenum and the ‘total’ PA reaching the duodenum were positively and significantly related to the microbial dry matter synthesised in the rumen. Free PA at the duodenum was significantly related to the dietary intake of free PA. The apparrent absorption of total PA within the small intestine was significantly related to the quantity entering the small intestine suggesting a passive absorption mechanism. It is suggested that CoA‐bound PA entering the small intestine is hydrolysed to release free PA which is then availab

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340503

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractSaccharification of ball‐milled winter wheat by an enzyme preparation fromTrichoderma reeseicontaining both cellulase and xylanase activities has been investigated. Straw from different cultivars of winter wheat differed in the amount of reducing sugars released by the enzymes and by the buffer alone. Although only seven cultivars were tested, differences in degradability of as much as 22% were recorded. Differences of this magnitude are likely to be of economic significance when considering the recycling of cereal straws. It is therefore important that account is taken of the cultivar of cereal straw to be use

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340504

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effects of an intra‐ruminal infusion of a mixture of methionine (7.0 g day−1) and sodium sulphate (6.7 g day−1) on the digestion of grass silage were examined in four sheep fitted with cannulas in the rumen and proximal duodenum. There were no significant (P>0.05) effects of the infusion on the ruminal digestion of OM, cellulose or N, or on the concentrations of total or individual VFA in the rumen fluid though the numbers of protozoa in the rumen were reduced (P0.05) apparently digested in the rumen for the control and infusion treatments respectively. The infusion resulted in a significant (P<0.01) increase of 21% in the amount of total long‐chain fatty acids at the duodenum. This reflected an increased flow of all fatty acids of chain‐length 14:0 and above though more than 80% the response was accounted for by the increased flow of 18:0 and 16:0 acids. It is concluded that the infused supplement stimulated the synthesis of microbial lipid i

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340505

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractUsing several cultivars, whole milled wheat grain was first extracted with 0.5M NaCl to remove non‐protein N, albumins and globulins: the amount of protein subsequently extractable by either 70% ethanol, 55% propan‐2‐ol, or 50% propan‐1‐ol (with or without the addition of acetic acid), was then compared. All solvents were tested at 4, 20 and 60°C both with and without the addition of 2‐mercaptoethanol (2‐ME) as a reducing agent. Raising the temperature, including a reducing agent, and repeated extractions, all combined to maximise protein extractability; least was extracted by 70% ethanol at 4°C and most by 50% propan‐1‐ol containing acetic acid and 2‐ME at 60°C. The differing polypeptide compositions of these alcohol‐soluble fractions illustrated why N solubility alone is not a sufficient guide to protein extraction, e.g. 35% of grain N was extractable by either 70% ethanol at 60°C or 70% ethanol containing 2‐ME at 4°C, but high mol. wt polypeptides (>60000) were found only in the 60°C extract. In contrast, the complete range of alcohol‐soluble polypeptides was extracted by all solvent mixtures based on propan‐1‐ol, even at 4°C. Amino acid analyses of these alcohol‐soluble fractions confirmed the low levels of lysine in fractions free from high mol. wt polypeptides. More glycine was found in all fractions containing high mol. wt polypeptides, but only those extracted by propan‐1‐ol mixtures had an increased lysine content, the amount of which increased linearly as the extraction temperature was raised. Defatting the milled grain did not affect the extractability of alcohol‐soluble proteins, but the amount of protein soluble in 0.5M NaCl decreased. The protein rendered NaCl‐insoluble was not extracted by any of the alcoholic solvents tested, hence the N content of the residual material was increased. The inclusion of this denatured metabolic fraction in the residue will affect its amino composition. The problems arising from the retention of the classical nomencl

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340506

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractPersistence of the organophosphorus pesticide, phosmet, in the milk of 10 dairy cows was determined following treatment of the animals for warble‐fly. The mean phosmet concentration in the milk was at a peak level (0.04 mg kg−1) 12 h after treatment. The extent of phosmet elimination in milk was related to the milk yield for each

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340507

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effects of post‐mortem storage and of a low‐calcium‐requiring neutral proteinase on the myofibrils of beefLongissimus dorsiandRectus abdominismuscles and rabbitLongissimus dorsimuscle were studied by measuring the Mg‐Ca‐enhanced myofibrillar ATPase activity and the changes in banding patterns on electrophoresis in sodium dodecyl sulphate. During ageing, the changes in the ATPase activity and myofibrillar proteins were qualitatively different between rabbit and bovine muscles, whilst differences in intensity were only observed between the two bovine muscles. The most prevalent component appearing upon conditioning had a mol. wt of 27 000 in rabbit muscle and of 30 000 in bovine muscles. In both species, the incubation of myofibrils with the low‐calcium‐requiring neutral proteinase mimicked the post‐mortem changes. This would suggest that this enzyme has a qualitatively different effect on rabbit and bo

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340508

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractCake staling, which is associated with changes in crumb firmness and moistness, has been shown to be related to two basic processes occurring in the crumb. These are an intrinsic firming process of the cell‐wall material of the crumb and the macroscopic migration of moisture from the central areas of the crumb to the dryer crust regions. The intrinsic firming process of the cell‐wall material of cake crumb is similar in character to that of breadcrumb and starch gels at temperatures up to 21°C. At higher temperatures it shows a significant deviation from the Avrami‐type polymer crystallisation kinetics used to describe the firming of starch gels and breadcrumb. The macroscopic migration of moisture is responsible for a secondary firming process which continues for periods of up to 5 weeks at ambient temperatures. It may also be responsible for the loss of moist‐eating quality in ca

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340509

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe time required to cook chickpeas (Cicer arietinum) varies from 55 to over 200 min. Seed weight and volume, swelling index and hydration capacity were found to correlate with cooking time. Correlation coefficients of between 0.65 and 0.75 were found for kabuli‐type (large seed) chickpeas, and coefficients of between 0.78 and 0.87 when desi types (small seed) were included. These relationships enable large numbers of chickpea genotypes to be screened rapidly into long, medium and short cooking time type

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340510

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractNine volatile constituents of a Muscat de Frontignan wine were selected as potentially important to the aroma of this wine by sniffing the chromatographic effluent following gas‐chromatographic separation of an aroma extract. Their concentrations were determined by mass fragmentometry and their olfactory thresholds estimated in a white base wine by calculating odour impact values. Ethyl‐cinnamate and β‐ionone contributed significantly to the aroma of the wine invest

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340511

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY