维生素C与氨基酸褐变反应的研究  

Study on the chemical reaction between Vc and amino acid

作　　者：李任强[1] 江凤仪[1] 方玲[1] 陈瑶[2] 

机构地区：[1]暨南大学生物工程学系,广州510632 [2]暨南大学化学系

出　　处：《食品工业科技》2002年第11期32-34,共3页Science and Technology of Food Industry

摘　　要：通过测定色变速度、pH变化和进行可见光吸收光谱的扫描等,考察了维生素C与氨基酸的反应。维生素C以极慢的速度向形成有色物方向变化,氨基酸首先以R基团而非α-氨基与维生素C分子反应,加速褐变。R基团中有氨基或芳香环的氨基酸与维生素C反应速度最快,惰性R基团的氨基酸与维生素C反应极慢。半胱氨酸对维生素C变化及色变有抑制作用。维生素C与氨基酸褐变的有色物的光吸收在340～400nm区域,主要来自于维生素C分子部分,色氨酸的吲哚环有助色作用。在实验的基础上分析了维生素C与氨基酸褐变反应的机理。The chemical reaction between vitamin C(Vc)and amino acid(A.A.)was studied throug h the measurements of the reaction speed,absorption spectrum in visible reg ion and pH chang e in Vc-A.A.samples.It was R g roup but not α-NH2in A.A.that reacted first to Vc to accelerate color chang e.Those A.A.with amino -g roup or aromatic ring in R g roup made the fastest reaction,and those with inactive R g roup made very slow reaction to Vc.Cysteine could prohibit Vc molecule chang e and color appearance.The obsorption spectrum of color product produced by Vc-A.A.reaction was in340-400nm reg ions,which was mainly due to Vc molecule.The indole ring of tryptophan was an auxochrome.

关 键 词：果蔬产品 维生素C 氨基酸 褐变 可见光吸收 羰氨缩合 

分 类 号：TS255.1[轻工技术与工程—农产品加工及贮藏工程]