Development Of A Fermented Tea-flower Cider

Tea flower is the reproductive organ of tea plants (Camelllia sinensis (L.) O.Kuntze),which is characterized with short life, long flowering period, high bloom productivity andlow seeding rate It has revealed that there are similar chemicals in tea flowers compared tothose in tea leaves, which provide their biological effects such as anti-oxidation,anti-cancer, lipid-lowering. Tea flowers are a rich and high valuable resource for thecomprehensive utilization and further processing of tea trees to develop new products infunctional foods, cosmetics and other industries.As a new defined food ingredient, the researches in tea flowers are still in thepreliminary stage of exploration. In this study, tea flowers were supplemented to theprocess of fruit wine fermentation to explore a novel fermented tea flower cider. The majorcontents in this thesis include the analysis ofchemical compositions in tea flowers, thescreening of fermentation yeast, the optimization of fermentation and follow-up clarifyingtechniques, the physical and chemical evalution of the final product.In order to obtain tea-flower tolerate cider yeast strain, a sysmatic screening wasapplied from tea garden soil and finally an aimed strain was identified as Saccharomycescerevisiae, named after tea-flower tolerate yeast Y15, by physiological, biochemical andmolecular approaches. It has founded that the fermentation performance of this strain wasweaken compared to that of the wine yeast LAL13. Therefore the twice fermentationstrategy was applied to improve the quality of the final cider product, in which thescreened yeast strain was added into the fermented suspension at the end of primaryfermentation by wine yeast.Based on the twice fermentation strategy, the individual fermentation factorswereoptimized and a response surface method was further introduced to optimize thefermentation conditions. The results showed that the best parameters for the fermentationwere as follwing: addition amount of the tea-flower amount to apple juice at1.0%(w/v),inoculum volume of wine yeast12.5%(v/v), initial sugar content200g/L, pectinase0.08g/Land fermentation temperature at27.0℃. The finished product was golden, clear withoutprecipitation. It also had a rich tea floral and fruity bouquet and a soft and mellow body.It’s a healthy low alcohol cider with unique flavor.Furthermore, five wine clarifiers as pectinase, bentonite, chitosan, diatomaceous earth,kaolin were applied separately in the clarifying treatment of tea-flower cider, the resultsshowed that the best clarifier was bentonite at the addition of0.8g/L for20h. In order to monitor the changes of catechins and amino acid compositions content ininitial fermentation liquid and finished wine, fermented by wine yeast and the combinationof wine yeast and tea-flower tolerate yeast, HPLC methods were applied and the resultsshowed that: the total of catechins and amino acids were decreased after fermentation，while the catechins in finished wines from two fermentation methods were similar.However, the content of amino acids in the final fermentation suspension by the twicefermentation method were three times higher than those only by wine yeast fementation,which caused by the apple juice as the seed liquid for the tea flower tolerate yeast.Finally, the main aroma components in tea flower cider were detected by solventextraction and static headspace methods with GC/MS. Some alcoholic components such asisoamyl alcohol, phenylethanol, and2,3-butanediol, aromatic esters such as4-hydroxybutyrate and ethyl acetate, isoamyl acetate, ethyl caproate, ethyl propionate,ethyl isobutyrate, isobutyl acetate, triethyl borate styrene, cyclohexanone and phthalatedioxide were identified as the main aromatic substances.