摘要:

AbstractThe response to loading of strips of ox sternomandibularis muscle varies greatly with degree of cooking. In raw or lightly cooked strips a yield point is reached where the myofibrils fail. Within this range, the yield point is independent of degree of cooking, and at 1.4 kg/cm2is well below the tension which can be developed in the pre‐rigor muscle (2.3 kg/cm2). On cooking, the yield point vanishes between 10 and 40 min at 70°C and the strips behave more elastically. This degree of heating coincides with the sharpest change in shrinkage and other properties. By using strips in which the myofibrillar component has been destroyed by alkali, and others in which collagen has been destroyed by long cooking, an attempt has been made to separate the contributions of these components. Between 60 and 80°C a fall in connective tissue strength is matched by a rise in myofibrillar strength, maintaining a constant overall value ofca5 kg/cm2. Both components become more extensible and stretch in unison, until they fail together. After cooking at 100°C, only the myofibrillar component survives (ca3 kg/cm2). Shear force values are generally in line with these results, but show a dip on cooking at 60°C, due to accelerated ageing. It is suggested that gap filaments may determine the tensile strength of the raw or cooked myof

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271002

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe volatile components of walnut oil obtained by solvent extraction were investigated. Two essences were prepared, one using the Likens–Nickerson concurrent distillation–extraction apparatus and the other by high vacuum degassing. The essences were submitted both to g.c.–m.s. analysis and sensory evaluation of the components eluted from g.c. capillary columns. Twenty‐nine compounds were identified, including 8 carbonyls, 4 alcohols, and 2 terpenes. The odour of walnuts appears to be due to the collective effect of a number of com

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271003

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractUsing previously reported methods of sample preparation an essence of garden cress was obtained which proved to contain only 11 components. Eight have been identified, all glucosinolate degradation products (isothiocyanates and nitriles), and provide over 95% of the sample. Benzyl derivatives, from glucotropaeolin, are the most abundant. No thiocyanates were obtained.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271004

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe freeze–thaw gelation of hen's egg yolk low density lipoprotein (l.d.l.) has been examined by viscometry, agarose gel filtration, electron spin resonance spectroscopy, electron microscopy and differential scanning calorimetry. The data indicate that the core lipids, the hydrocarbon chains of interfacial lipids of l.d.l. and the sulphydryl, imino, amino and tyrosine groups in the side chains of l.d.l. peptides are not directly involved in the gelation mechanisms. The gelation is caused by non‐specific aggregation due to cross‐linking of peptides and/or phospholipid polar head groups of adjacent l.d.l. particles. During freezing, interparticle contacts are formed and strengthened as transformation of solvent water into ice increases the concentration of the particles. Salt and sugar additives inhibit large increases in concentrations of l.d.l. during freezing and prevent gelation by helping to increase solvation of interfacial regions of the l.d.l. particles. Agents that induce large viscosity increases in the l.d.l. sols before freezing may act by producing a local conformational change in l.d.l. protein and/or disrupting lipid–protei

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271005

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThree different plant sterol fractions were added to refined cottonseed oil. The first fraction was isolated from olive oil, the second fraction Δ5‐avenasterol was extracted from the green algae (Ulva lactuca) and the third fraction was a sterol mixture, made up chiefly of β‐sitosterol. Cottonseed oil with the different sterols added was heated at 180±5°C and the rate of oxidation followed by changes in the composition and in physical constants. Olive oil sterol mixtures containing Δ5‐avenasterol and Δ5‐avenasterol alone reduced the extent of oxidation. β‐sitosterol was initially ineffective and became slightly prooxidant after p

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271006

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe lipid content and fatty acid composition of New Zealand eel speciesAnguilla australis(short‐fin) andAnguilla dieffenbachii(long‐fin) in both the feeding and the migratory phases were studied. Migratory short‐finned eels were found to have a higher lipid content than feeding eels. Among feeding eels the lipid content was higher in larger eels. The lipids of migratory eels were more saturated than those of feeding eels due to higher proportions of C18 acids and correspondingly lower proportions of C20 and C22 polyunsaturates. Among feeding eels, the lipids of the long‐finned species were more highly unsaturated than those of short‐fi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271007

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractSamples of hulls, of whole and ground caryopsis and of bran obtained from the Brazilian rice variety IAC 1246, were extracted with hexane and the characteristics and composition of the corresponding lipids were determined. The lipids from rice hulls showed a four times higher content of unsaponifiable matter and of free fatty acids than those from rice bran and rice caryopsis. There were also differences in the fatty acid composition as evidenced by the presence of 2–3% of saturated C22and C24acids and a lower proportion of unsaturated acids in the rice hull lipids. On the other hand there was a close resemblance between the rice hull lipids and those on the surface of the caryopsis. Chromatographic analysis of the unsaponifiable matter of lipids from rice hulls and caryopsis surface disclosed the presence of hydrocarbons, alcohols and sterols in ascending order, the sterols consisting of about 50% of β‐sitosterol, 20–40% of campesterol, 10–20% of stigmasterol and 2–3% of cholesterol. On the basis of the above results it was concluded that a preliminary solvent extraction of paddy rice in order to remove the waxy lipids from the hulls and the caryopsis surface would benefit the subsequent milling process and improve the quality of the brown rice and of crude ric

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271008

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractAspergillus flavusLink ex Fr., was used to evaluate the relative nutritive value in a set of breeder's material involving 2 rye, 5 wheat and 33 triticale samples ranging in protein content from 12.6 to 21.9%. The samples were tested at equal nitrogen level. Total dry weight of the mycelium produced after 72 h of shaking was used as the index of biomass. The biomass showed a negative correlation with protein content and dye‐binding capacity, and a positive correlation with protein index and lysine in protein. The fungus was able to pick up an “unusual” sample which had high protein and high lysine content. In addition, the effects of initial inoculum concentration, pH value and excess soluble starch on biomass production were studied. Initial spore concentrations of 106and 108/ml and pH values of 3.5 and 6.2 did not make significant changes in biomass. However, the presence of excess soluble starch increased the mycelial yield without basically altering the results. Lysine dependent strains ofNeurospora crassaandAspergillus nidulansdid not grow well in shake cultures and it appeared that the carbohydrate energy source was left unutilised. This “left over” starch was considered to be a possible source of error in biomass dete

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271009

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractSpent bone charcoal from a sugar refinery was compared with dicalcium phosphate as a source of phosphorus for young sheep given a low phosphorus diet. The apparent digestibility of both forms of phosphorus was similar. Dicalcium phosphate and spent bone charcoal supplementation resulted in positive phosphorus retentions of +0.61 and +0.90 g P/day respectively compared with a daily loss of −0.29 g P/day for the low phosphorus diet. Both forms of phosphorus addition increased blood phosphorus concentration

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271010

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractHeat treatment (dipping seeds in boiling water) of two cultivars ofBrassica napus, 1788 and 940, low in glucosinolates and erucic acid produced improved weight gains and lower thyroid weights in rats who received these meals as the only source of protein. Unheated cv 940 meal on autolysis did not produce detectable amounts of nitriles and increased weight gains were observed in rats ingesting the autolysed meal. Steaming of unheated meal similarly gave increased weight gains and the effects of steaming and autolysis were additive. The rates of weight gain of rats who ingested unheated and heated meals were different for the first ten days of feeding the meals but subsequently were similar, indicating the possibility of palatability factor(s) or another appetite depressing factor(s) being present in unheated meals. Trypsin inhibitor activities determined for various rapeseed meals were low as compared to soybean. Chlorogenic acid and myrosinase, both known constituents of rapeseed, did not show any trypsin inhibitor activity.In vitrodigestibility measurements with pancreatin and pepsin didnot show significant differences between heated and unheated meals nor did anin vivodigestibility trial, although the rats consumed less of the feed containing unheated meal.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740271011

出版商:John Wiley&Sons, Ltd    

年代:1976

数据来源: WILEY