5种新疆特色植物色素的理化特性及其降解动力学研究

Physicochemical properties and degradation kinetics of five Xinjiang characteristic plant pigments

对提取自5种新疆特色植物的花青素类色素进行理化特性、抗氧化活性和降解动力学研究,结果表明:不同色素提取物的颜色响应差异显著(P<0.05);黑枸杞色素(BWP)含有5种单体化合物,以锦葵素3-O-葡萄糖苷含量最高(23.18μg/g DW);桑葚色素(MMP)含有4种单体化合物,以矢车菊素3-O-半乳糖苷含量最高(300.87μg/g DW);玫瑰花色素(RFP)含有7种单体化合物,以飞燕草素3-O-葡萄糖苷含量最高(144.34μg/g DW);葡萄皮色素(GPP)含有7种单体化合物,以飞燕草素3-O-葡萄糖苷含量最高(116.45μg/g DW);紫苏叶色素(PLP)含有3种单体化合物,以矢车菊素含量最高(144.10μg/g DW)。其中,GPP耐热性最好,降解初始温度为165.71℃。不同色素提取物热降解过程均符合一级反应动力学模型;当pH值为3.0时,PLP最稳定,活化能(E_(a))为22.539 kJ/mol;当pH值为7.0时,RFP最稳定,E_(a)为13.851 kJ/mol。相关性分析表明色素提取物中花青素的含量与其抗氧化活性有显著相关性(P<0.05);RFP的体外抗氧化活性最强,其IC_(50DPPH)和IC_(50ABTS)分别为7.32μg/mL和71.50μg/mL,总抗氧化活性(T-AOC)为4073.00 U/g DW。

In this study,five anthocyanin pigments were extracted from Xinjiang characteristic plants,and the physicochemical properties,antioxidant activities and degradation kinetics of these pigment extracts were explored.The results showed that there were significant differences in color responses of different pigment extracts(P<0.05).The black wolfberry pigments(BWP),medicine mulberry pigments(MMP),rose flower pigments(RFP),grape peel pigments(GPP),and perilla leaf pigments(PLP)mainly contained 5 compounds,4 compounds,7 compounds,7 compounds,and 3 compounds,respectively.The compounds with the highest content in five pigment extracts were malvidin 3-O-glucoside(23.18μg/g DW),cyanidin-3-galactoside(300.87μg/g DW),delphinidin-3-O-glucoside(144.34μg/g DW),delphinidin-3-O-glucoside(116.45μg/g DW),and cyanidin(144.10μg/g DW),respectively.Furthermore,GPP showed the highest heat resistance with a degradation temperature of 165.71℃.The thermal degradation of different pigment extracts conformed to the first-order reaction kinetics.Meanwhile,PLP showed the highest stability at pH 3.0,with a corresponding energy of activation(E_(a))was 22.539 kJ/mol.While RFP was the most stable at pH 7.0(E_(a)=13.851 kJ/mol).Correlation analysis showed that there was a significant correlation between the content of anthocyanins in pigment extracts and their antioxidant activity(P<0.05).In addition,RFP exhibited the strongest antioxidant activities in vitro,and its 50%inhibiting concentration(IC_(50))on DPPH and ABTS radicals(IC_(50))were 7.32μg/mL and 71.50μg/mL,respectively,the total antioxidant activity(T-AOC)was 4073.00 U/g DW.