紫薯醋发酵工艺优化及品质分析

采用单因素结合响应面法优化紫薯醋酸发酵条件,同时发酵得到紫薯醋和紫薯色素回添醋,并对2种醋和紫薯原料的品种指标进行测定及比较。优化后的紫薯醋酸发酵条件为发酵时间11 d、初始酒度7.35%vol、装液量28%,此条件下,总酸含量为6.92 g/100g。与原发酵工艺相比,紫薯色素回添醋除总糖和维生素含量较低外,其总酸、总酯、总多酚、总黄酮、花青素含量和抗氧化能力均显著优于紫薯醋(P<0.05)。与紫薯原料中的活性成分相比,紫薯醋中总多酚、总黄酮、花青素含量较原料分别损失75.59%、63.63%和72.75%,采用新发酵工艺可使损失率分别降低10.34%、15.61%和42.93%。挥发性成分分析显示2种紫薯醋中鉴定出的挥发性成分的化合物数量相差不大,种类却有较大差异。同时,紫薯花青素的提取过程会导致一些对醋品香气有贡献的化合物损失。

Fermentation process optimization and quality analysis of purple sweet potato vinegar

The single factor combined response surface method was used to optimize the fermentation conditions of purple sweet potato acetic acid,and the original purple sweet potato vinegar and purple sweet potato pigment added vinegar were obtained by fermentation at the same time.These two kinds of vinegar and purple sweet potato raw materials were analyzed and compared.The optimal conditions for purple sweet potato acetic acid fermentation were:fermentation time 11 days,initial alcohol content 7.35%vol,liquid loading 28%.Under these conditions,the total acid content was 6.92 g/100 g.The content of total acid,total ester,total polyphenol,total flavone,anthocyanin and antioxidant capacity of the added purple sweet potato pigment vinegar were higher than those of the original purple sweet potato vinegar except for the lower content of total sugar and vitamin(P<0.05).Compared with the active components in raw materials of purple sweet potato,the contents of total polyphenol,total flavone and anthocyanin in raw purple sweet potato vinegar lost 75.59%,63.63%and 72.75%respectively,and the loss rate decreased 10.34%,15.61%and 42.93%.And there was no significant difference between the number of volatile components identified in these two purple sweet potato vinegars,but the types were different.However,the extraction process of anthocyanin from purple sweet potato led to the loss of some compounds that contribute to the aroma of vinegar.