Studies On Isolation And Identification Of Predominant Microbes From Acid Tea And Fermentation Technology Of Tea Wine

1. Isolation and identification of predominant microbes from acid teaAs a fermented food product acid tea is wide-ranging and long-time consumption or drinking in Yunnan Minority, Thailand and Myanmar. In this study, the predominant microbes of natural fermented acid tea were isolated and identified. The main findings are as follows:Microbial environment in the acid tea is not complicated that only two types of microorganisms:Lactic acid bacteria and Yeast were isolated from the acid tea.8bacteria selected from separation plates all were identified as Lactobacillus plantarum and2strains of yeast both were Canadida maltosa. Compared the ability of acid production,3of Lactobacillus plantarum (No. A1, L2and L5) were selected and were suitable for acid tea fermentation.2. Study on the fermentation process of tea wine made of fresh tea leaves in SummerIn this study, fresh leaves of tea(Camellia sinensis) as the main material, changes of the sensory quality and main components of tea wine during the fermentation were studied. Through analyzing the changes of main components of tea wine by single-factor and orthogonal experiments, the optimum fermentation technology of tea wine was obtained. Storage conditions were tested and the health qualities of tea wine were analysed.The main results are as follows:Based on the single factor experiments, the fermentation conditions were preferred that tea material was obtained by direct extraction after fixing, tea ratio(m/v) was1:60, the initial pH value was natural, and the fermentation temperature is28℃. Orthogonal experiments on three factors, namely inoculum size, sugar content and fermentation time were conducted, and the best combination is A2B2C2with2.5%(v/v) of inoculum size,10%(m/v) of sugar and7days of fermentation.In the dynamic changes of tea wine quality, the conventional ingredients of tea declined rapidly in the first day of fermentation, and gently at the following days; alcohol content and total acid content showed a gradual increasing trend and leveled off late in the fermentation; the sensory quality achieved the best between the fourth to eighth day in the fermentation.The main quality components of tea wine were analysed. Tea polyphenols was1.32g/L, flavonoids0.04g/L, amino acid0.04g/L, caffeine0.09g/L, TF0.23g/L, TR14.63g/L, TB6.72g/L, soluble sugar13.83g/L and alcohol content1.17%. Compared to the control(tea wine fermented0h), TP, flavonoids and TF changed little; and amino acids, caffeine, TR, TB, soluble sugar and SSC were decreased with extremely significant (P<0.01); and total acid was increased and pH value reduced.The largest proportion of aroma components in tea wine is alcohols, mainly phenethyl alcohol with48.69%relative content. Amino acids in tea wine significantly declined, especially threonine, glutamic acid, y-propalanine and lactamine, only lysine with a weak increase. Catechins in tea wine reduced10.97%compared with the control. EGC and EGCG decreased,12.77%and15.53%, respectively. GA, GC, EC, GCG and ECG declined little and only C increased.In the health indexes of tea wine, arsenic is0.012mg/kg, and lead(Pb) is0.008mg/kg. Total number of colonies in tea wine is less than10CFU/mL, coliform bacteria<30MPN/100mL, mould<10CFU/mL, yeasts<10CFU/mL. The pathogenic bacterium (Salmonella, Shigella, Staphylococcus aureus) were not detected out.Storage temperature, storage time and their interaction have significant effects on the chromaticity, transmittance, the SSC content, acid content and TP content of tea wine. Considering the TP and acid content tea wine should suit to preservate low-temperature and under-40days.