低聚壳聚糖的美拉德反应及其衍生物的抗氧化性能研究

醇沉法制得低聚壳聚糖美拉德反应8、16 h以及24 h的衍生物,分别记为CC-8、CC-16以及CC-24。对3种衍生物进行红外表征和分子量测定,并研究其对超氧阳离子O 2&、DPPH的清除能力以及还原能力。结果显示:反应体系pH呈下降趋势;UV-Vis光谱在280 nm波长处吸收峰有明显增强,反应16 h后增长缓慢;在343 nm的激发波长和420 nm发射波长下的荧光强度明显增高,反应16 h后开始下降;3种衍生物均保留着低聚壳聚糖的特征吸收峰;其对O 2&、.DPPH的清除能力以及还原能力均得到显著提高,且CC-16抗氧化能力最好。

The Maillard reaction of chitosan oligosaccharide and the antioxidative activities of its derivatives

Three kinds of chitosan oligosaccharide derivatives prepared through Maillard reaction by heating chitosan oligosaccharide for 8, 16 and 24 hours were named CC-8, CC-16 and CC-24, respectively. The pH, absorbance and fluorescence were determined during the reaction. Chitosan oligosaccharide derivatives were characterized by Fourier transform infrared (FTIR) spectroscopy and their molecular weights were determined by Gel permeation chromatograph (GPC). Their antioxidative activity was investigated by employing various established in vitro systems, such as superoxide anion, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging, and their reducing capacity was also studied. The results showed that the pH value of the reaction system decreased during Maillard reaction. The UV-Vis absorbance increased significantly at 280 nm and this increase slowed down after 16 hr. The fluorescence intensity significantly increased with Ex at 343 nm and Em at 420 nm and also slowed down after 16 hr. All the three derivatives kept the characteristic absorption peak of chitosan oligosaccharide. Their antioxidative and reducing capacities were both much stronger than those of the chitosan oligosaccharide and CC-16 has the strongest antioxidative activity.