桑葚酵素发酵过程中活性物质与抗氧化能力的相关性研究

Correlation between active substances and antioxidant capacity during mulberry Jiaosu fermentation

为改善自然发酵酵素工艺、缩短发酵周期及标准化评价体系,该研究以桑葚为原料,探究发酵过程中的主要活性物质对产品抗氧化性的影响,并利用主成分分析法,构建桑葚酵素的综合评价体系。桑葚酵素发酵过程中还原糖及pH值不断下降,随后趋于平稳,而总酸变化与之相反;总酚与总黄酮的变化相似,在发酵40 d时达到最大值,分别为3.42 g/L和3.60 g/L,之后略有下降;发酵过程中共检测出8种有机酸,主要为乳酸、乙酸、酒石酸、柠檬酸、琥珀酸,其中变化最大的乳酸和乙酸,其含量分别从初始的0.46 g/L和0.77 g/L升至11.10 g/L和7.05 g/L。相关性及主成分分析结果表明,除柠檬酸外,其他活性物质均与体外抗氧化指标有显著的相关性(P<0.01),且桑葚酵素综合评价指标于30 d达到最大值,可作为前发酵结束的依据。

In order to improve the natural fermentation enzyme process,shorten the fermentation cycle and standardized evaluation system,this study uses mulberry as raw materials to explore the impact of the main active substances on product antioxidant properties in the fermentation process,and constructed a comprehensive evaluation index(CEI) system of mulberry Jiaosu by using principal component analysis.The results showed that the reducing sugar and pH value decreased continuously and then tended to be stable,while the change of total acid was opposite;the changes of total phenols and total flavonoids were similar.They reached the maximum at 40 days of fermentation,which were 3.42 g/L and 3.60 g/L respectively,and then decreased slightly.Eight kinds of organic acids were detected in the fermentation process,mainly lactic acid,acetic acid,tartaric acid,citric acid and succinic acid.The contents of lactic acid increased from 0.46 g/L to 11.10 g/L and that of acetic acid increased from 0.77 g/L to 7.05 g/L.The results of correlation and principal component analysis showed that except citric acid,other active substances had significant correlation with in vitro antioxidant indicators(P<0.01),and the CEI of mulberry enzyme reached the maximum at 30 days,which can be used as the basis for the end of pre fermentation.