以糯米藕为原料,采用乙醇水溶液浸提法,通过单因素及正交实验L9(34)确定糯米藕中类黑精的最佳提取工艺参数。结果表明:影响糯米藕中类黑精提取效果的主次因素顺序为:提取温度>乙醇体积分数>提取时间>料液比。最佳提取条件为:以体积分数10%乙醇为提取溶剂,料液比1∶40(g∶mL),浸提温度80℃,浸提时间1.5 h。在此条件下,糯米藕提取液中的类黑精量(AV值)为8.235。以糯米藕类黑精提取液为研究对象,测定不同浓度类黑精提取液的1,1-二苯基-2-三硝基苯肼自由基(DPPH·)和羟基自由基(·OH)清除能力和还原力。结果表明:随着类黑精浓度的增加,这3种抗氧化活性指标均显著增强(P<0.05),且当相对浓度在1.0(提取原液)时达到最强,即DPPH·清除能力为53.39%,·OH清除能力为10.16%,还原力为15.95%;同一浓度梯度下,DPPH·自由基清除能力最强,其次为还原力,·OH清除能力最小。糯米藕类黑精具有较好的抗氧化活性,并存在一定的量效关系。

In order to optimize the parameters for the aqueous ethanol extraction of Melanoidin from Chinese traditional lotus roots filled with sticky rice,the single factor and L9(34) orthogonal experimental design were applied.The results showed that the extraction temperature was the principal factor,followed by ethanol concentration,extraction time,and solid-liquid ratio.The optimum extraction condition was that the grinded lotus roots was immersed into10% ethanol water solution with a ratio of 1∶ 40(w /v),maintaining for 1.5 h at 80℃.Under this condition,AV value of extraction of Melanoidin reached 8.325.The antioxidant activities of Melanoidin in the extracts were estimated by scavenging capacities of a 2,2-diphenyl-picrylhydrazyl radical(DPPH·),hydroxyl radical(·OH) and reducing power under different concentrations.We found that the antioxidant activities of three indexes significantly increased(P < 0.05) with the increasing concentration of Melanoidin,and when the relative concentration was 1.0,the three indexes of antioxidant activities reached to 53.39 %,10.16 % and 15.95 %,respectively.The extracts DPPH· scavenging capacity was the highest,followed by reducing power and ·OH scavenging capacity.It was concluded that Melanoidin in Chinese traditional lotus roots filled with sticky rice had of good antioxidant activity and has a dose-effect relationship.