食品加工中晚期糖基化终产物的变化趋势及茶多酚对其抑制作用

The Change Trend of AGEs in the Food Process and Inhibition Function of Tea Polyphenols

晚期糖基化终产物(AGEs)是食品加工和贮藏中美拉德反应、脂质氧化反应或葡萄糖氧化等多种途径中的产物,在人体内积累后能够引起一些慢性疾病,如糖尿病、肾病、高血脂等,因此抑制晚期糖基化终产物具有重要意义。采用葡萄糖(Glc)与牛血清白蛋白(BSA)模拟食品加工中产生的糖基化产物反应过程,以茶多酚为抑制剂加入反应体系中,通过NBT法测定果糖胺,高效液相色谱法(HPLC)测定乙二醛(GO)和羧甲基赖氨酸(CML),荧光法测定AGEs来检测糖基化反应的早、中期和晚期产物,根据蛋白质羰基和巯基含量和蛋白质相对分子质量变化,获得茶多酚抑制晚期糖基化终产物的主要机制。试验结果表明:在食品加工条件下茶多酚对糖基化反应的中间产物果糖胺、乙二醛有明显抑制作用,对CML和荧光性AGEs有一定抑制作用。SDS-聚丙烯酰胺凝胶电泳表明茶多酚与蛋白质的相互作用引起蛋白质二级结构的变化,阻止蛋白质交联。结合茶多酚对蛋白质巯基的保护作用,茶多酚既以抗氧化作用参与抑制糖基化反应,又对蛋白质的交联反应有抑制作用。

Advanced glycation end products（AGEs） are a type of complicated reaction products by Maillard reaction, lipid oxidation or glucose oxidation in food processing and storage. They accumulated in the human body and caused some chronic diseases such as diabetes, kidney disease and high cholesterol. Glycosylation process was simulated with glucose（Glc） and bovine serum albumin（BSA） at 70 ℃ and tea polyphenols were added to the reaction system as natural inhibitor in this paper. Fructosamine was measured by NBT reagent, glyoxal and carboxymethyl lysine（CML）were measured by HPLC, and early, mid and end glycosylation products were detected by fluorescence spectrum. The main mechanism of tea polyphenols inhibiting advanced glycation endproducts was achieved by these results and determination of protein carbonyl, sulfhydryl groups, protein relative molecular weight. The results showed that tea polyphenols significantly inhibited intermediate product fructosamine and glyoxal, stronger inhibition than that of CML and fluorescent AGEs in food processing. Tea polyphenols can react with protein, leaded to the change in protein secondary structure and prevented protein form cross-linking reaction by SDS-polyacrylamide gel electrophoresis, on the whole, Tea polyphenols not only participated in anti-oxidation inhibition of glycosylation, but also inhibited protein cross-linking reaction.