KINETICS AND MECHANISM OF THE REACTION BETWEEN 3-DEOXYHEXOSULOSE AND THIOLS

被引：11

作者：

EDWARDS, AS

WEDZICHA, BL

机构：

[1] Procter Department of Food Science, University of Leeds, Leeds

来源：

FOOD ADDITIVES AND CONTAMINANTS | 1992年 / 9卷 / 05期

关键词：

NONENZYMIC BROWNING; MAILLARD REACTION; ANTIBROWNING AGENT; THIOL; N-ACETYLCYSTEINE; GLUTATHIONE; KINETICS;

D O I：

10.1080/02652039209374098

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

The kinetics of the reaction of 3-deoxyhexosulose, DH, with mercaptoethanol, ME, and glutathione, GSH, resemble those of the DH-sulphite reaction, but the stoichiometry of the DH-thiol reaction is 1:2 unlike that of the DH-sulphite reaction which is 1:1. However, the rate determining step in all these reactions is the spontaneous conversion of DH to a reactive intermediate, followed by a rapid reaction of this intermediate with the nucleophile. This is also true of the reaction between DH and N-acetylcysteine, NAC, but this thiol is less reactive than ME or GSH and less than one mole of NAC reacts with each mole of DH. Evidence for instability of NAC ai pH 5.5 is presented. Aminothiols (cysteine, homocysteine, cysteamine) undergo a fast reaction with DH followed by a slow release of thiol. The initial reaction is probably formation of a thiazolidine. In the case of cysteine and homocysteine it is suggested that the subsequent slow step is a Strecker degradation reaction. The kinetic behaviour of thiols in cabbage homogenates is reported.

引用

页码：461 / 469

页数：9

共 9 条

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