红枣核桃酸奶的贮藏品质及胃肠液环境下抗氧化研究

以红枣、核桃、新鲜牛奶为主要原料制备红枣核桃酸奶,以不添加红枣汁与核桃粉的同批鲜奶自制普通酸奶为对照,分别测定不同贮藏时期红枣核桃酸奶和对照酸奶的理化指标,以及两种酸奶在贮藏期和胃、肠液模拟环境下对DPPH、ABTS自由基的清除能力。结果表明,贮藏期间红枣核桃酸奶在活菌数、酸度以及抗氧化能力方面均显著优于对照酸奶(P<0.05),持水力低于对照酸奶(P<0.05),且贮藏21 d后,红枣核桃酸奶的DPPH和ABTS自由基清除率分别为88.65%、72.46%,对照酸奶为53.10%、69.44%。然而,两种酸奶经延长冷藏时间或在胃肠液环境处理后均会导致自由基清除能力降低,但红枣核桃酸奶在总体上仍然优于对照酸奶。因此,红枣核桃酸奶是一种新型的功能性乳品。

Storage quality of jujube walnut yoghurt and its antioxidation in gastric and intestinal fluid environment

Jujube walnut yoghurt was prepared with jujube,walnut and fresh milk as main raw materials,and the same batch yoghurt without jujube juice and walnut powder was used as control.The physicochemical indexes of jujube walnut yoghurt and control yoghurt in different storage periods were determined,and the DPPH and ABTS free radicals scavenging abilities of the two yoghurt during storage period and simulated environment of gastric and intestinal fluid were measured.The results showed that the viable count,acidity and antioxidant capacity of jujube walnut yoghurt were better than those of the control yoghurt(P<0.05),and the water holding capacity was significantly lower than that of the control yoghurt(P<0.05).After storage for 21 d,the DPPH and ABTS free radical scavenging rates of jujube walnut yoghurt was 88.65%,72.46%,and the scavenging rates of the control yoghurt was 53.10%,69.44%,respectively.However,the free radical scavenging ability of the two kinds of yoghurt would be reduced after prolonged storage time or treatment in gastrointestinal fluid environment,but the jujube walnut yoghurt was still superior to the control yoghurt in general.Therefore,jujube walnut yogurt is a new type of functional dairy.