摘要:

AbstractA method useful for the determination of cadmium, cobalt, copper, iron, lead, manganese, nickel and zinc in diets is described. Organic matter is destroyed applying a wet procedure, and element content is measured by flame atomic absorption spectroscopy (FAAS) in the case of copper, iron, manganese, nickel and zinc, and by graphite furnace (GF‐AAS) in the case of cadmium, cobalt and lead. The matrix interference study is carried out. Values found for linearity, detection and quantitation limits as well as accuracy show that the described method is useful to determine the elements taken into account at usual levels in diet

ISSN:0027-769X    

DOI:10.1002/food.19910350702

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19910350704

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe mean values of alpha and beta‐carotene of 10 fruits and vegetables from supermarkets in Cairo and Alexandria have been determined using HPLC method, and the average vitamin A activities (in retinol equivalents) calculated. Carrots, spinach and sweet potatoes were the best sources of provitamin A activity. Beta‐carotene was the more prevalent carotenoid compared with alpha‐carotene. An analysis of variance including all foods investigated demonstrated that there were no significant differences among either locations or times of analysis. There was no difference between the analysed values of vitamin A activity and the USDA Handbook No. 8 v

ISSN:0027-769X    

DOI:10.1002/food.19910350705

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19910350707

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractMittels gekoppelter Kapillar‐Gaschromatographie/Massenspektrometrie werden die Fettsäureprofile von verschiedenen Hefe‐ und Bakterienlipiden sowie vonPorphyridium cruentum(Rotalge) undWolffia arrhiza(Wasserlinse) analysiert. Auf Kohlenwasserstoffen kultivierte Hefen unterscheiden sich von “Kohlenhydrathefen” durch einen hohen Gehalt an ungeradzahligen Fettsäuren (Anteil bis zu 50 %), während Bakterienlipide vor allem durch das Auftreten cyclischer, hydroxylierter und verzweigter Fettsäuren charakterisiert sind. In den untersuchten Wasserpflanzen können bis zu 30 % Arachidonsäure (Porphyridium cruentum) bzw. 60 % Linolsäure (Wolffia arrhiza) nachg

ISSN:0027-769X    

DOI:10.1002/food.19910350708

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractDas rheologische Verhalten von grobzerkleinertem, vorgesalzenem Fleisch wurde mit Hilfe der Rotationsrheometrie während des Stehenlassens und bei unterschiedlichen Wasserzusätzen untersucht. Es ergab sich ein enger Zusammenhang zwischen Fließverhalten und Wasserbindungsvermö

ISSN:0027-769X    

DOI:10.1002/food.19910350709

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe aim of this work has been to study the temporal evolution during the vegetative stages of the composition of linoleic and linolenic acids, lipoxygenase activity and C6aldehyde content in Macabeo grapes. Linoleic acid was found to be the main fatty acid, especially in skin and pips, and higher levels of linolenic acid have been found in the polar lipid fraction, and in the pulp. Lipoxygenase activity is higher during the semi‐ripe stage, and the aldehydes are not direct products of lipoxygenase action. There appears to be no direct relationship between the contents of linoleic and linolenic acids, lipoxygenase activity and C6aldehydes in Macabeo grapes during their vegetative stages. All these results suggest that in addition to lipoxygenase other enzyme systems must be involved in the metabolic processing of unsaturated fatty acids to C6aldehyde

ISSN:0027-769X    

DOI:10.1002/food.19910350710

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractDie Aufarbeitung von Wasser‐, Boden‐ und Lebensmittelproben mit einer modifizierten Glasapparatur zur simultanen Wasserdampfdestillation/Lösungsmittelextraktion wird erprobt. Zusatzversuche mit 22 vorwiegend halogenhaltigen Pflanzenschutzmitteln und PCB ergaben nach einer Destillationsdauer von 1,5 h bei Wasserproben bzw. bis zu 5 h bei Boden‐ und pflanzlichen Lebensmittelproben gute bis sehr gute Wiederfindungen. Durch den geringen Lösungsmittelverbrauch (<10 ml) ist dieses Verfahren umweltfreundlich und kostengünstig und für viele Fragestellungen als schnelle Screeningmethode

ISSN:0027-769X    

DOI:10.1002/food.19910350711

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19910350713

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractNew criteria for the evaluation of wheat qualitative properties are worked out on the basis of the study of the shape and size of the extensographic curves. Approximating the experimental curves ‐ extensograms ‐ to the theoretical curves which are the closest to them in their shape and equal to them in their area, it also was possible to determine their shape parameters. The theoretical curve is an ellipse inscribed over the shape of the experimental curve. It changes its shape to the case when the ellipse eccentricity becomes equal to zero and further when x‐axis and y‐axis exchange their places in the coordinate system. It has been determined that the extensogram area can be the best means of measuring the wheat flour quality if it has been evaluated with reference to the curve circumference which circumscribes it. The ratio of the parameters of the theoretical curve maximum (mt) and the maximum of the theoretical curve of the ideal shape (r) is the basis for the extensogram evaluation and their classification into the qualitative range. The quantitative data of the ratio mt/r indicate the shape, and the values for r indicate the extensogram size. On the basis of the expression (mt/r‐1)100, it is possible to evaluate accurately the extensographic curves for the first time as well as to classify wheat into the qualitat

ISSN:0027-769X    

DOI:10.1002/food.19910350715

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY