摘要:

AbstractTwenty‐one Monocotyledon and 59 Dicotyledon seed samples, nine pollen samples and 12 fractions of seeds were analysed for their content of dry matter, total nitrogen and glycoprotein and total hexosamine. An estimate was made of the frequency of occurrence of hexosamine in the proteins of the samples. The dry matter contents (as g per 100 g sample) showed little variation (88.0‐95.1, seeds and 84.1‐90.9, pollens). The total nitrogen contents (as g per 100 g sample) varied from 0.84‐3.29 (Monocotyledons), 1.42‐7.13 (Dicotyledons) and 2.91‐5.43 (pollens). The glycoprotein hexosamine content (as mmol per 100 g sample) varied from 0.078‐0.32 (Monocotyledons), 0.11‐0.73 (Dicotyledons) and 0.36‐0.78 (pollens). The frequency of occurrence of hexosamine in the proteins (as hexosamine residues:amino acid residues) varied from 1:450 to 1:1940 (Monocotyledons), 1:300 to 1:3640 (Dicotyledons) and 1:330 to 1:760 (pollens). The decomposition of hexosamines during prolonged acid hydrolysis prevented accurate estimates of non‐protein hexosamine contents being obtained but the results indicated that they varied from a few percent of, to about equal to, the contents of glycoprotein hexosamine in t

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291102

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA simplified technique is described in which the fluorescence of a crude extract of red clover is used to predict the formononetin content. A high correlation (r≥0.95) was found between the proposed method and formononetin determined chromatographicall

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291103

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractFinely ground seeds of wheat, sunflower, coffee and french bean were either hydrolysed in acid directly, or after extraction with ethanol and/or after treatment in alkali to hydrolyse anyO‐acetyl sialic acids present. The acid hydrolysates were fractionated by ion‐exchange chromatography. Sialic acid was not detected in any of the materials examined but quinic acid was found in all of them. It is concluded that some previous reports of sialic acid in plant seeds and tissues may have been due to the presence of quinic acid and of other compounds, which show rather similar properties to sialic acid in chromatographic and colorimetric methods of analy

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291104

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe procedure, which has been devised for the measurement of three excretory products in ruminant's urine, is based on a two‐stage ion‐exchange chromatographic separation of purines using the resins Dowex 50W × 4 (200‐400 mesh) in the hydrogen form and Dowex 1‐chloride 1 × 10 (50‐100 mesh) converted into the acetate form; followed by enzymatic conversion of hypoxanthine and xanthine to uric acid and of uric acid to allantoin. The recoveries of hypoxanthine plus xanthine and of uric acid were 90‐99% and 95‐9

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291105

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA short digestion method for Kjeldahl nitrogen determination, using a trace of selenium as catalyst and described in this paper, gives results comparable to the American Association of Cereal Chemists (1976) method using mercuric oxide catalyst, for all compounds tested except for nicotinic acid. However, nicotinic acid is a minor component of food materials and it is not normally assayed by the Kjeldahl method. Selenium, like mercury, is known to be toxic7but mercury ranks more highly than selenium as an environmental problem.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291106

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractFour methods of analysing for oil content of avocados are compared (three with gravimetric measurements): (a) Soxhlet extraction with petroleum ether, (b) homogenisation with petroleum ether, (c) homogenisation with a 2:1 (by volume) choroform/methanol solution, and one with refractmetric measurement, i.e. (d) ball milling with 1‐chloronaphthalene. Conditions for Soxhlet extraction were optimised. Methods (a) and (b) gave similar results which were 6‐9 % lower than those of methods (c) and (d) which were similar to each other. Saponification of the residues from methods (a)‐(c) confirmed that method (c) removed more oil than methods (a) and (b) but also showed that even method (c) left some residual oil in the fruit tissues. Results are interpreted in terms of glycolipids and phospholipids remaining after extraction of triglyceride storage fractions by petroleum ether. All methods used were applicable to hard (unripe) and soft (ripe) f

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291107

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractTrona (Urao) popularly known in Ghana as kawe is used for medicinal and tenderiser purposes (especially in reducing the cooking time of cowpea). The type of kawe found in Ghana contained predominantly 25.0% sodium with small amounts of other metals. Cooking cowpeas in the presence of kawe reduced the cooking time from 75 to 50 min which represents a saving of time and fuel to the cooker.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291108

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractOil content and composition, protein content and grain weight have been estimated in 86 barley genotypes from diverse sources grown in a replicated field experiment. Overall range between genotypes in composition was: oil content, 1.9‐4.1 %; palmitic, 21.4‐28.7%; stearic, 0.6‐1.8%; oleic, 10.4‐16.9%; linoleic, 52.4‐58.3%; linolenic, 4.5‐7.3%. Modern European varieties varied from 2.2‐2.8% oil, and oil content was higher in two‐rowed than six‐rowed types and higher in naked than husked types. Protein content was higher in naked than husked types, but there was no significant difference between the protein content of two‐ and six‐rowed types. Mean grain weight was higher in both two‐rowed and in husked types. Oil was positively correlated with grain protein and the proportion of oleic acid, and negatively correlated with the proportions of palmitic and stearic acid. The highest oil contents were found in Rise 1508 and Hiproly which ar

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291109

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe fatty acids of the total lipid extracts made from 10 tropical storage organs(Alocasia macrorrhiza, Colocasia esculenta, Dioscorea alata, D. bulbifera, D. cayensis, D. rotundata, Ipomea batatas, etc.) were studied. The high occurrence of the C18unsaturated fatty acids (linoleate and linolenate which together contributed over 50 % on average of the total fatty acids), conferred a high level of unsaturation on almost species. Compared with similar storage organs of temperate regions, there was a definite reduction in the degree of unsaturation. This was brought about by a general increase in the intrinsic values of palmitate and oleate.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291110

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe amounts of gel formed when wheat flours are suspended in 1m acetic acid or in phenol‐acetic acid‐water (1:1:1, w/v/v) are highly correlated with the total nitrogen contents and the Zeleny sedimentation values of the flours. It is concluded that the Zeleny sedimentation test depends on the formation of this gel. Gel formation in acidified aqueous suspensions is markedly affected by the ionic strength and pH of the suspending medium, but not by non‐polar molecules or reagents that react specifically with sulphydryl groups or disulphide bonds. The gel is readily dispersed by ultrasonic treatment and gel formation is prevented completely by the amounts of sodium chloride added to dough during breadm

ISSN:0022-5142    

DOI:10.1002/jsfa.2740291111

出版商:John Wiley&Sons, Ltd    

年代:1978

数据来源: WILEY