Study On The Technology Of Tea Vinegar Beverage Fermented By Summer And Autumn Tea Leaves

The summer and autumn tea leaves urgently need to be developed and utilized for they were seriously wasted.One kind of tea vinegar was fermented by these procedures:tea infusions were extracted from the pretreated summer and autumn fresh tea leaves,and alcohol was added and microbial culture was inoculated to ferment.It provides a efficient path of developing and utilized summer and autumn fresh tea leaves and enriches tea bioproducts.The results were followed:1.The technology of tea vinegar beverage fermented by summer and autumn tea leavesBased on the sensory qualities and chemical qualities,the fermentation technology of tea vinegar was optimized by single factor experiments and orthogonal test.In single factor experiments,the fermentation conditions of adding 50 g/L sugar,60%relatively volume of liquid,150 r/min rotate speed,initial pH value,no salt added,and fermentation temperature 28℃ were better to form the quality of tea vinegar.In orthogonal test,the optimal fermentation technology was of adding 20 ml/L alcohol,40 ml/L inoculum and 28 d fermentation time.2.The dynamic regularity of tea vinegar’s quality formationDuring 60 days of tea vinegar’s fermentation period,the results were that:the pH value was down significantly before 12 days,and then kept much stable;the total acid sharply increased before 8 days,and then kept much stable;the soluble solids and soluble sugar were much stable during the fermentation process;flavonoids and polyphenols fell slightly before 4 days,and then kept much stable.The free amino acid and caffeine were down significantly before 4 days,and the free amino acid did not detected during post-fermentation,but caffeine had a gradual upward trend during post-fermentation.After fermented 12 days,color,aroma and taste of tea vinegar changed significantly,and the wine became weak gradually and disappeared,and the fruit fragrance and vinegar fragrance became thick and soft,and the acidity also gradually become soft."Sour but not astringent,fragrant and slightly sweet,with thick color and fresh fragrance,and longer storage and more fragrant".3.The characteristics of tea vinegar’s qualityThe tea vinegar fermented by the optimal conditions has a amber of color with loster,and its texture is uniform,clear and transparent;its fragrance both with the characteristics of tea and vinegar,is soft;and its taste is soft with the appropriate ratio of sweetness and acidity.In the fermented tea vinegar,pH value is 2.94,total acid is 665.03 g/L,soluble solid is 4.96%,polyphenol is 1.53 g/L,soluble sugar is 37.60 g/L,and the sensory score is 90.67.Compared with the unfermented sample,C and EC of tea vinegar fell by 20%and 32%,respectively;caffeine was declined about 40%,EGCG increased about 133%,and total catechins increased about 39%.Its aroma components are more abundant,and there are 48 kinds of aroma substances more than 0.05%.The quality and safety indicators of tea vinegar meet national standards.4.The features of tea vinegar’s storageDuring 70-day storage process,pH value,total acid,polyphenol and soluble solid of tea vinegar under 37℃ and 45℃ changed significantly.Their color turn into red,there were turbid and sediment.Totally,the qualities of tea vinegar storaged under 4℃ was the best.