凤冈锌硒夏秋茶发酵饮品发酵过程动态评价

Dynamic Evaluation of Fermentation Process of Fenggang Zinc-Se Summer-Autumn Tea Fermentation Beverage

以凤冈锌硒夏秋茶为原料,红茶菌为发酵菌种,以感官审评、功能成分、风味物质为指标,探究夏秋茶发酵过程中的动态变化。结果表明,感官审评上,发酵5 d,发酵液香气浓郁,滋味酸甜可口,有厚厚生物膜漂浮,发酵趋于稳定,状态较好,适于饮用;功能成分上,整个发酵过程中,茶多酚含量逐渐降低,茶氨酸含量逐渐增加,发酵第5天,茶多酚降低的比例和茶氨酸增加的比例均变慢,说明发酵第5天,发酵逐渐趋于稳定,锌含量在整个发酵过程中呈不规律性变化,硒含量在整个发酵过程中趋于稳定;风味物质上,6个发酵期(0、1、3、5、7、9 d)共检测到107种风味物质,包括醇、醛、酸、酯、烷烃、酮及其他类化合物,其中乙醇和醋酸含量最高;偏最小二乘-判别分析(PLS-DA)显示3个发酵期(5、7、9 d)挥发性风味物质组成相似,说明发酵至5 d时主体风味化合物已经形成;发酵过程中关键风味物质(OAV≥1)有21种,3个发酵期(5、7、9 d)夏秋茶发酵饮品风味贡献较大的关键风味物质相同,均是醋酸、(E)-2-庚烯醛、大马士酮。因此,夏秋茶发酵5 d,口感最佳,主体风味化合物已经形成,功能成分含量逐渐趋于稳定,确定5 d为最优发酵期。

Fenggang zinc-Se summer-autumn tea was taken as main raw materials,Kombucha was used as a kind of fermentation fungus,the dynamic changes of summer-autumn tea fermentation process was explored with sensory evaluation,functional components and flavor substances as indicators.The results showed,on sensory evaluation,after 5 days of fermentation,the fermentation broth had a strong aroma,a sour and sweet taste,a thick biofilm floating.the fermentation tended to be stable,and the condition was good and suitable for drinking.On functional component,the whole fermentation process,the tea polyphenol content gradually reduce,theanine content increased gradually,the reduced proportion of tea polyphenols and increased proportion of theanine were slow at the 5th day of fermentation,it is meams fermentation gradually stabilized,zinc content is not a regular variation in the fermentation process,the selenium content in the stable in the fermentation process.On flavor substances,107 flavor substances were detected in 6 fermentation periods(0,1,3,5,7,9 d),including alcohols,aldehydes,acids,esters,alkanes,ketones and other compounds,among which ethanol and acetic acid had the highest content.Partial least squares discriminant analysis(PLS-DA)showed that the compositions of volatile flavor compounds were similar in the three fermentation stages(5,7,9 d),indicating that the main flavor compounds had been formed at the 5th day.There were 21 kinds of key flavor substances(OAV≥1)in the fermentation process.The key flavor substances that contributed more to the flavor of summer and autumn tea fermentation drinks were the same in the three fermentation stages(5,7,9 d),which were acetic acid,(E)-2-heptenal and dammasone.Therefore,after 5d fermentation,summer and autumn tea has the best taste,the main flavor compounds have been formed,and the content of functional components gradually tends to be stable,which is the optimal fermentation period.