摘要:

AbstractAn efficient, yet relatively inexpensive combined gas chromatography‐mass spectrometry‐odour port unit has been used to follow the changes in the volatiles of cooking apples during cooking. Since headspace samples contained insufficient volatiles for mass spectrometric identification, they were isolated by a Likens and Nickerson extractor, the pentane extract being concentrated before examination. The volatiles were collected during successive intervals from the same cooking sample. Alcohols were prominent throughout the exaggerated cooking time of 6.5 h and were accompanied by varying amounts of hexanal, phenylacetaldehyde, damascenone and farnesenes. In the early stages, several esters were present in amounts sufficient for identification, but no evidence of their later evolution and of the accompanying apple odours was obtained. 2‐Furfural, benzaldehyde. 5‐methyl‐2‐furfural and 2,4‐decadienal were not detected initially, but contributed increasingly later, 2‐furfural finally becoming the predominant volatile.A taste panel established a highly significant difference between cooked apple prepared fresh from Bramley's stored at +5 °C for 5 months and blast‐frozen precooked apple, stored for 5 months at −20 °C and made originally from the same batch of Bramley's. The former was preferred as being less acid and having more apple flavour. Instrumental comparison of extracts prepared by the above methods showed that precooked frozen apple stored for only 1 week contains relatively higher concentrations of esters and ofn‐hexanal than after 5‐months' storage, when traces of the decadienal were found. The sensory and instrumental evaluations thu

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230702

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractAqueous extracts of rapeseed meals were separated into four fractions by Sephadex (G25) column chromatography. Fraction I was found to be rich in protein as judged by nitrogen and amino‐acid content and u.v. absorbance at 280 nm. Fraction II contained glucosinolates and peptide‐like materials. Fractions III and IV contained only trace amounts of amino acids and nitrogen. Further separation of fraction IV into three components was achieved by chromatography on silicic acid. Two of the components were shown, by paper chromatography and u.v. absorbance scanning, to be rich in caffeic acid and chlorogenic acid, respectiv

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230703

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe effects of interesterification and fatty acid supplementation on the nutritive value of homogenised fats in milk replacers for calves were studied in two digestibility experiments, each of a 6 × 6 latin square design. Using a level of 20% added fat, the mean apparent digestibilities of the total dietary lipids were: butterfat, 96.5%; interesterified butterfat, 95.5%; tallow, 88.7%; interesterified tallow, 93.1%; tallow supplemented with trimyristin and triolein by interesterification, 92.3%; tallow supplemented with trimyristin and triolein by simple admixture, 89.9%. The high digestibility of butterfat is not dependent apparently on any specific non‐random distribution of its constituent fatty acids. The digestibility of the tallow was lower and interesterification just failed to give a significant improvement. The inclusion of additional myristic and oleic acids had no significant effect.Using a level of 15% added fat, the mean apparent digestibilities of the total dietary lipids were: tallow, 79.7%; interesterified tallow, 89.2%; interesterified, reduced stearic acid, tallow 87.9%; interesterified, reduced stearic acid, added butyric acid, tallow, 96.3%; interesterified, added butyric acid, tallow 94.7%; tallow admixed with tributyrin, 84.0%. The inclusion in tallow of butyric acid by a process involving interesterification resulted in substantial increases in digestibility to values similar to those obtained for butterfat and interesterified butterfat in the first experiment. The improvement was not achieved by simple admixture of tributyrin with tallow. Reduction of the stearic acid content in tallow to a level similar to that in butterfat had no significant effect on fat digestibility.The lower digestibility of tallow than of butterfat was due mainly to lower digestibility of palmitic and stearic acids and a higher percentage of the latter acid in tallow. Modifications which effected an improvement in the digestibility of tallow generally did so by improving the digestibility of these aci

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230704

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA date extract known locally in Iraq as “dibis” was used as substrate for mycological fat formation byPenicillium lilacinum, P. soppiiandAspergillus nidulans.The three fungi were grown on dibis medium at three concentrations. Carbohydrates readily disappeared but this was accompanied by poor fungal growth and low yields of fat.Fungal growth on dibis media enriched with asparagine led to heavy mycelial yields together with higher fat contents. Both economic and fat coefficients rose considerably. It is concluded that nitrogen deficiency in dibis media is at least one of the major factors against good fungal growth and high fat format

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230705

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe acid‐induced conformation changes between 7 and 11 S globulin, the major storage proteins in soybean seeds, were compared by ultraviolet difference spectra, ultracentrifugation and optical rotatory dispersion. Maximum denaturation occurred at approximately pH 2 in both and dissociation of the proteins into subunits and unfolding of the polypeptide chains were observed simultaneously. However, both proteins showed apparent differences in their readiness to undergo acid‐induced denaturation. The differences were particularly remarkable in the presence of 0.1 ionic strength sodium chlor

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230706

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractFeeding experiments with mice suggest that high‐molecular weight compounds in rapeseed meal without direct relationship to glucosinolates have a detrimental effect on the nutritional value of the meal. This effect is precluded by treatment with ethanol or upon heating. Ethanol extraction improves the nutritional value of the residue as a result of the removal of non‐essential nitrogenous compounds.The nutritional value of the seed meal of the cultivar Bronowski was superior to that of the high‐glucosinolate meal. A freeze‐dried ethanol extract of the high‐glucosinolate cultivar Sv Rigo was toxic to mice, especially when fed in combination with myrosinase, in contrast to ethanol extract from the low‐glucosinolate cultivar Bronowski. A decrease of the glucosinolate content to a level below that of Bronowski did not effect the growth respo

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230707

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractAn investigation of the composition of garlic skins showed the presence of proteins, lipids, lignin, mannitol, pectin and polysaccharides. Garlic skins are rich in pectin (27%), combined rhamnose (11.42%) and galactose (5.6%). Periodate oxidation studies of pectic acid showed the absence of 1,3‐linked residues and branch points and indicated a linear galacturonan of 1,4‐linked D‐galacturonic acid. Chromatographic analyses were carried out on the hydrolysis products of pectic acid, which had been oxidised by periodate plus bromine, and also on those obtained after reduction of the periodate‐oxidised pect

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230708

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractStream sediments were sampled systematically in nine areas totalling 1100 sq. milesThroughout this paper 1 sq. mile = 2.589 km2.underlain in part by marine black shales ranging in age from Ordovician to Cretaceous. Regional patterns of molybdenum in the sediment were related to the underlying bedrock. Soils developed from the black shale parent material together with associated pasture herbage in eight of the areas contained above normal concentrations of molybdenum (>3 parts/million).Detailed studies in four of the areas confirmed the high molybdenum content of stream sediment, rock, soil and pasture. Examples are shown of the importance of both glacial drift and of specific soil factors such as pH in the interpretation of geochemical reconnaissance data for agriculture. Clinical hypocuprosis in cattle is already recognised over parts of two of the molybdenum‐anomalous areas. In the other two, copper deficiency disorders are not recognised but may well occur at a sub‐clinical level. It is suggested that appreciable acreages of the United Kingdom underlain by marine black shales may be enriched in molybdenum and be potentially limiting to livestock performa

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230709

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractAddition of small amounts of either sodium chloride or magnesium salts to thick egg white inhibited the natural thinning processes. Chemical analyses of the ovomucin complex and analytical ultracentrifugation of fully reduced derivatives obtained from thick egg white incubated at 37 °C showed that either 0.01 M‐magnesium salt or 0.03 M‐sodium chloride also reduced the losses of the β‐ovomucins which normally occur during liquefaction of thick egg white. A possible mechanism by which magnesium and sodium chloride retard egg white liquefaction is discussed in relation to the known effect of these substances on ovomucin‐lysozyme interactions. A proposed commercial application of the findings is

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230710

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractGel filtration of the proteins isolated from orange juice showed three fractions. The two with higher molecular weight were used to prepare rabbit immunosera. By testing the immunosera with concentrated orange and lemon juice substantial differences between the proteins of these two citrus fruits were demonstrated. Our research has also shown that these sera can be used for analysis of commercial products.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740230711

出版商:John Wiley&Sons, Ltd    

年代:1972

数据来源: WILEY