Mundt Sandra, Wedzicha Bronislaw L
Procter Department of Food Science, University of Leeds, Leeds LS2 9JT, United Kingdom.
J Agric Food Chem. 2004 Jun 30;52(13):4256-60. doi: 10.1021/jf035381p.
The composition of melanoidins formed in the reactions of either glucose or maltose with glycine (70 degrees C, pH 5.5, [glucose] = [maltose] = [glycine] = 0.25 M) (MW > 3500) was investigated by microanalysis and the use of (14)C-labeled sugars and amino acid. The most reliable parameter obtained from microanalysis data is the C/N value, as it was calculated with no model assumption. The C/N value (7.6 +/- 0.2 for glucose and 10.5 +/- 0.2 for maltose) does not change with molecular weight (MW > 3500) as the polymers grow in size. A comparison between the radiochemically determined composition and that obtained from microanalysis suggests that the amino ketone, which is one of the products of Strecker degradation reaction, forms part of the of the melanoidin structure, together with the sugar-derived moiety and the Strecker aldehyde. Evidence is presented that glucose is formed at intermediate stages of the maltose-glycine reaction. The melanoidins are the result of the polymerization of glucose and intact, or substantially intact, maltose residues with glycine.
通过微量分析以及使用碳 - 14标记的糖和氨基酸，研究了葡萄糖或麦芽糖与甘氨酸在反应中形成的类黑素组成（70℃，pH 5.5，[葡萄糖]=[麦芽糖]=[甘氨酸]=0.25M）（分子量>3500）。从微量分析数据中获得的最可靠参数是C/N值，因为它的计算没有模型假设。随着聚合物尺寸增大，C/N值（葡萄糖为7.6±0.2，麦芽糖为10.5±0.2）不会随分子量（分子量>3500）而变化。放射化学测定的组成与微量分析所得组成之间的比较表明，作为斯特雷克降解反应产物之一的氨基酮，与糖衍生部分和斯特雷克醛一起构成了类黑素结构的一部分。有证据表明在麦芽糖 - 甘氨酸反应的中间阶段会形成葡萄糖。类黑素是葡萄糖与完整或基本完整的麦芽糖残基和甘氨酸聚合的结果。
