摘要:

Soybean lipoxygenase‐I was incubated with18O2‐13‐S‐hydroperoxy 9‐cis, 11‐trans octadecadienoic‐acid. It was shown, by18Ocontent, degree of racemisation and of isomerisation that the enzyme catalysed the exchange of molecular oxygen with the oxygen atoms of the OOH group which is stereoselectively retained in the 13(S) conjiguraton a

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00078.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Endopolygalacturonase [poly (1–4‐α‐D galacturonide) glycanhydrolase, EC 3.2.1.15] activity was measured in samples of cv. Rutgers, Nr (never ripe) and F1hybrids of rin (ripening inhibitor, + rin, ++), nor (nonripening, ++, + nor) and rin × nor (+ rin + nor) fruits taken at three day intervals during ripening. Day 1 of ripening was taken as the day on which the first persistent increase in ethylene production was recorded. The enzyme was first detected on day 3 in Rutgers, F1rin and F1nor, and on day 6 in Nr and F1rin × nor. The Rutgers and F1rin samples softened more rapidly than the other samples and they also contained more enzyme activity. Enzyme activity developed less rapidly in Nr than in any other samples, but the Nr and the nor hybrid, samples softened at comparable rates. In Rutgers and F1rin, a high molecular weight form of the enzyme (PG1, Mr 100 000) predominated to day 6, and a lower molecular weight form (PG2, Mr 43 000 ‐ 46 000) progressively increased after day 6. In all F1nor, F1rin × nor and Nr samples the enzyme was predominately or entirely as PG1. The interrelationship of PG1 and PG2 and their roles in ripening ar

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00079.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Molds and bacteria contaminate parboiled rough rice when it is improperly dried or while awaiting drying due to humid rainy weather. When IR 20 parboiled rough rice was not dried for 7 days due to humid weather molds increased to 2.45 × 107per gram from 6 × 104per gram and bacteria increased to 75.9 × 106per gram from 5.1 × 106per gram observed initially. The milled rice yield decreased to 60.1% from 72.2% and the head rice yield decreased to 55.0% from 98.8% due to infection. The resultant bran contained only 12.1% oil compared to 31.9% in normally dried and milted paddy with about 40.0% free fatty acids in oil. The infection induced breakdown changes increased the levels of sugars, amino acids and polyphenols in grains which might cause kernel discolouration in the associated heat development during infect

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00080.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Cell‐free extract (CFE) from Streptococcus lactis var. maltigenes was examined for its ability to catalyze the formation of 3‐methyl butanal and 3‐methyl butanol from leucine as affected by pH, substrate concentration and gradual addition of NADH. Pseudo Kmand vmax, determined for CFE were 6.5 × 10‐3M and 7.1 μmol/liter‐min when 3‐methyl butanal was measured and 9.4 × 10‐3M and 2.4 μmol/liter‐min for 3‐methyl butanol. The CFE, leucine and cofactors were encapsulated in milkfat and incubated for 40 h at 22°, Rate of formation and final concentration of 3‐methyl butanal and 3‐methyl butanol were related to substrate concentration, indicating that flavor intensity can be controlled with encapsulated enzymes by limiting substrate concentration. Diffusion of 3‐methyl butanol and acetic acid from microcapsules was affected by concentration and their lipophilic/hydrophilic character. Altering the pH of fluid surrounding microcapsules containing CFE had limited effect on the internal pH, as indicated by enzyme probes, demonstrating that capsules provide an environment isolated

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00081.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A new method of determining pectinolytic activities was developed with the aid of dye‐substituted substrate. Soluble stained pectic acid proved to be the most suitable substrate for the agar diffusion, the cupplate and the inoculation test, especially for screening purposes. Insoluble stained pectic acid was used as an enzyme substrate in the photometric test. The sensitivity of the method of 2 × 10‐2μmol of reducing groups liberated per min per ml of enzyme may be considered satisfa

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00082.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Books Reviewed in this Article:Decelopments in Food Proteins 1., Edited by B.J.F. Hudson. Applied Science Publishers, London and New Jersey. 1982 $70.00.Modification of Proteins, Food, Nutritional, and Pharmacological Aspects. Edited by Robert E. Feeney and John R. Whitaker. American Chemical Society, Washington, 1982. $54.95.Decelopments in Food Carboydrate‐3. Edited by C.K. Lee and M.G. Lindley. Applied Science Publishers, Ltd., 22 Rippleside Commercial Estate, Ripple Road, Barking Essex 1G11 OSA, England. 217 pp. 1982. $52.0

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00083.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

ErratumThe bookMembrane Structure and Function, Vol. 1. Edited by E.E. Bittar. John Wiley&Sons, Inc. New York, 1980 was reviewed in Issue No. 2 of Vol. 6, J. Food Biochem. The reviewer was erroneously given as Herbert O. Hultin. George M. Carman reviewed the book.

ISSN:0145-8884    

DOI:10.1111/j.1745-4514.1983.tb00084.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY