摘要:

AbstractDurch die verbreitete Verwendung partiell gehärteter Fette ist der Verzehr an trans‐Fettsäuren in diesem Jahrhundert stark gestiegen. Wir entwickelten eine sensitive Analysenmethode, die eine präzise Bestimmung von 7 trans‐Fettsäuren in kleinen Probenmengen erlaubt. Hiermit wiesen wir den materno‐fetalen Transport von trans‐Fettsäuren über die menschliche Plazenta nach. Der Gehalt in menschlicher Milch hängt von der mütterlichen Ernährung ab und ist in Deutschland höher als im Sudan. Die Verteilung in Vor‐ und Nachmilch, in Milchfettfraktionen und innerhalb der Triglyceridmoleküle wurde untersucht. In handelsüblichen und hausgemachten Säuglings‐Milchnahrungen liegt die trans‐Belastung niedriger als in Muttermilch, wobei eine gewisse Chargenvariation besteht. Säuglinge absorbieren trans‐Isomere aus der Nahrung und inkorporieren sie in körpereigene Lipide, Fettgewebe und Zellmembranen. Trans‐Fettsäuren in Plasmalipiden sind bei Muttermilchfütterung signifikant höher als bei Formelernährung. Afrikanische Kinder haben eine signifikant niedrigere Belastung als deutsche. Im Plasma ist der relative Beitrag der trans‐Octadecensäure in Sterinestern geringer als in Triglyceriden und Phospholipiden, was für eine negative Selektivität der plasmatischen Cholesterol‐Veresterung mit dieser Fettsäure spricht. Deshalb könnte eine hohe Zufuhr an trans‐Octadecensäure ungünstige Wirkungen auf den Cholesterolspiegel haben. Bei Frühgeborenen finden wir eine inverse Korrelation zwischen trans‐Fettsäurebelastung und kindlichem Geburtsgewicht, so daß eine Störung des intrauterinen Wachstums möglich erscheint. Als eine Ursache kommt eine gestörte Biosynthese sehr langkettiger Polyenfettsäuren in Betracht, für die wir Hinweise fanden. Unsere Ergebnisse stellen die Unbedenklichkeit des Konsums von trans‐Fettsäuren bei

ISSN:0027-769X    

DOI:10.1002/food.19910350302

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19910350304

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effects of different types of dietary fat on the digestive and metabolic utilization of protein were studied in rats with 50% resection of the distal small intestine and in sham‐operated controls one month after surgery. The digestive utilization of protein was not significantly affected in intact animals when olive oil was replaced by butter as the dietary source of fat. In resected rats given either type of diet the apparent digestibility coefficient of protein declined significantly in comparison to intact controls. Intestinal resection decreased the retention of nitrogen significantly in rats given olive oil. The replacement of 2/3 of the dietary supply of olive oil with 1/3 medium chain triglycerides and 1/3 sunflower seed oil improved the metabolic utilization of protein in comparison to resected rats fed olive oil or butter as the only source of dietary fat. However, the addition of ursodeoxycholic acid to the diet containing equal parts of olive oil, medium chain triglycerides and sunflower seed oil failed to improve the metabolic utilization of protein in comparison to that seen in rats given olive oil only. Serum concentrations of total protein, urea and creatinine, albeit with slight changes in the first, remained within normal limits. Despite the lower retention of nitrogen in resected rats, these animals maintained homeostasis without resorting to muscular protei

ISSN:0027-769X    

DOI:10.1002/food.19910350305

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe influence of acylation on surface functional properties, solubility and heat‐induced aggregation of the low‐molecular weight basic protein fraction (napin) from rapeseed was studied. While the native protein was soluble over the whole pH‐range, the exhaustively acetylated one became precipitable in the weakly acidic range. Acetylation of 70–80% of the protein amino groups caused a stabilizing against heat‐induced aggregation. The native protein had a high foam capacity and stability which were only slightly changed after acylation. Decreasing volume specific work in the order native>acetylated>succinylated protein pointed, however, to an improved foamability of acylated napin. Succinylation increased the interfacial tension on the oil/water interface, while acetylation gave both an increasing and a decreasing effect depending on the degree of modification. The emulsifiying capacity decreased after acylation in the order native>acetylated>suc

ISSN:0027-769X    

DOI:10.1002/food.19910350306

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19910350308

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractProtein concentrates were prepared from fenugreek seeds by extraction with distilled water, salt solution and alkaline solution. Alkaline solution resulted in the highest extraction yield (82%). The protein concentrate has a good digestibility (over 90%) as determined by in vitro enzymatic method. The protein is rich in lysine (6.51%) but poor in sulphur‐containing amino acids such as methionine (0.71%), cystine (1.09%) and tryptophan (1.03%

ISSN:0027-769X    

DOI:10.1002/food.19910350309

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe toxic effects of the γ‐hexachlorocyclohexane metabolite γ‐pentachlorocyclohexene (γ‐PCCH) were studied by acute and subacute (6 weeks) experiments. The investigations included cerebral convulsibility with chemoshock (Tetrazolium), reactivity with hot plate method, the learning ability with learning tests, and peripheral nervous activity (EMG). Nociceptive reaction time was not influenced, the learning process (6 weeks) was inhibited by γ‐PCCH. The conduction velocity of the peripheral nerve was decreased. At the end of the 6th week liver enlargemen

ISSN:0027-769X    

DOI:10.1002/food.19910350310

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractProtein conformation is one of the key factors which determine the behaviour of a protein in solution. During the isolation and processing into foodstuffs proteins may undergo significant conformational changes, involving structural changes on different levels — from the secondary level to the submolecular one. One of the most urgent problems related to food protein processing is the regulation of the conformational changes of proteins in order to obtain steady structures with desirable functional properties [1].The present work is concerned with the effect of pH on the conformational stability of Ribulose 1,5‐Bisphosphate Carboxylase (RBPC) from tobacco leaves. This protein constitutes 50% of the soluble proteins in green leaves of plants [2]. RBPC is an oligomeric enzyme which consists of 16 noncovalently linked subunits: large and small with a molecular mass of 55 and 14 kDa, respectiv

ISSN:0027-769X    

DOI:10.1002/food.19910350311

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

ISSN:0027-769X    

DOI:10.1002/food.19910350313

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractSweet potato (Ipomoea batatas) is a good source of carbohydrates and carotene [3, 5], and contains a relative low amount of protein, minerals [7]and ascorbic acid [6].This work is an attempt to evaluate the changes of proteins, minerals, sugars, starch, ascorbic acid and carotenoids during boiling and baking of sweet potatoes.

ISSN:0027-769X    

DOI:10.1002/food.19910350314

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY