【作者】 王忠合； 薛晓丽； 王军； 于淑娟；

【Author】 WANG Zhong-he,XUE Xiao-li,WANG Jun,YU Shu-juan (College of Light Industry and Food Sciences,South China University of Technology,Guangzhou 510640,China)

【机构】 华南理工大学轻工与食品学院；

【摘要】 美拉德反应是含有羰基的化合物与含有氨基的化合物经缩合、聚合而生成类黑精的反应,它是加工食品色泽和风味的主要来源,同时影响加工工食品的营养及安全性。美拉德反应中间产物的带电荷基团可与金属离子发生反应,抑制或促进某些化合物的形成,最终可能产生活性不同的美拉德反应金属离子配合物。本文研究了Cu²⁺离子对葡萄糖-甘氨酸模式美拉德反应的影响,高浓度的Cu²⁺离子（0.05～0.2 M）可促进美拉德反应的褐变程度,而低浓度的Cu²⁺离子（0.005～0.05 M）则抑制美拉德反应的褐变。pH电位滴定法证实美拉德反应产物具有良好的配位能力,且随着反应时间的增加,类黑精上结合的金属离子数量增加。美拉德反应中形成的还原酮具有抗氧化性和还原性,可将乙二醛或乙二醛亚胺还原成乙醇醛,进一步反应生成较稳定的自由基,并释放出电子,从而将Cu²⁺还原成单质铜。更多还原

【Abstract】 Maillard reaction,or nonenzymatic browning,started from an initial reaction of a reducing sugar with an amino compound, followed by a cascade of consecutive and parallel reactions to form a variety of colored and colorless products which range from flavor volatiles to melanoidins.It affected the quality of processed food products,in particular the sensory attributes,had an effect on nutritive value or toxicological implications.Maillard reaction intermediates containing negatively charged groups readily reacted with metal ions,which inhibited or promoted the formation of some compounds,and eventually produced different reactive metal complexation.The objective of this paper was to determine the influence of copper(Ⅱ) ions on the different stages of Maillard reaction in a glucose-glycine model system and to elucidate the mechanism of copper(Ⅱ) ions incorporated into the melanoidins or intermediates.The presence of higher concentrations copper(Ⅱ) ions (0.05～0.2 M) stimulated the accumulation of colored compounds,but lower concentrations copper(Ⅱ) ions(0.005～0.05 M) suppressed browning of the model mixtures.Potentiometric proton-liberation measurements showed that the formation of complexes of crude Maillard reaction products(MRPs) with copper.The relative amounts of metal ions incorporated into the high molecular weight melanoidins increased initially with the reaction time.The mechanisms of radical formation revealed that reductone can initiate radical formation upon reduction of glyoxal and/or glyoxal imines into the effective radical precursor glycolaldehyde,which leads to the free copper released again from the model mixtures in the Maillard reaction.更多还原