以精氨酸/赖氨酸-麦芽糖、壳聚糖-果糖/阿拉伯糖为模式制备美拉德反应产物,考察4种体系紫外可见光谱和荧光光谱随加热时间的变化,氨基与羰基物质的量比、初始pH、温度对产物褐变的影响及反应过程的pH值变化,探讨美拉德反应产物对DPPH·、HO·、H2O2的清除作用和总还原力。结果表明:4种体系紫外吸收峰均在260~280 nm,荧光激发波长在319~335 nm、发射波长约在420 nm和385 nm(壳聚糖-阿拉伯糖)。4种体系的褐变及精氨酸/赖氨酸-麦芽糖的酸度均随加热时间的延长而增加,壳聚糖-果糖/阿拉伯糖的酸度变化则无规律。当氨基与羰基物质的量比为1∶2~1∶3,pH 11~12和温度110~120℃时,各体系的褐变接近最大程度。精氨酸/赖氨酸-麦芽糖体系对DPPH·清除作用均随浓度增大而降低,对HO·清除作用均基本保持不变;对H2O2的清除作用和总还原力均表现出一定的量效关系。壳聚糖-果糖/阿拉伯糖体系对DPPH·的清除、HO·的清除及H2O2的清除作用均随浓度增大而增强,总还原力先增大后减小。

Maillard reaction products( MRPs) were prepared using arginine /lysine-maltose and chitosan-fructose /arabinose. The changes of ultraviolet-visible( UV-Vis) and fluorescence spectroscopy,the effects of amount of substance ratio of amino to carbonyl group,initial pH,temperature on browning of MRPs and pH changes during reaction process were investigated. The scavenging capacity of MRPs on DPPH,hydroxyl free radical,H2O2and total reducing power were also observed. The results showed that UV absorption peaks of four kinds of MRPs were 260 ~280 nm,excitation wavelengths 319 ~ 335 nm and emission wavelengths of three kinds of MRPs were about 420 nm and 385 nm for chitosan-arabinose. The browning of four kinds of MRPs and acidity for arginine /lysine-maltose all increased with the heating time,but acidity for chitosan-fructose /arabinose changed irregularly. Browning all reached to their maximum when the amount of substance ratio of amino to carbonyl group was 1∶ 2 ~ 1∶ 3,pH 11 ~ 12 and temperature 110 ~ 120 ℃,respectively. With the increasing of MRPs concentration for arginine /lysine-maltose,scavenging capacity on DPPH decreased,hydroxyl free radical was almost not changed,H2O2and total reducing power showed a dose-response relationship to some degree. For chitosan-fructose /arabinose,scavenging capacities on DPPH,hydroxyl free radical and H2O2increased with concentration increase,but total reducing power increased to maximum and then decreased. The study provided theoretical basis for preparation and the antioxidant activity of MRPs.