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標題: Effects of Using Pure Culture Cultivation and Cellular Immobilization On the Microbial Activities and Production of Major Metabolites During the Fermentation of Kombucha
作者: 林文祺
Lin, Wen-Chi
關鍵字: 紅茶菇
tea fungus
acetic acid bacteria
acetic acid
pure culture
出版社: 食品科學系
摘要: Abstract The kombucha (or tea fungus) is a symbiotic culture of having acetic acid bacteria and yeasts as two major microorganisms. The tea fungus is composed of two portions, a floating cellulose pellicle layer and thesour liquid broth. Acetic acid, ethanol, and gluconic acid, are the major components found in the liquid broth. The fermentation is traditionally carried out by transplanting a previously cultivated symbiotic culture, accompanied with the product cellulose, into a freshly prepared sucrose containing black tea under aerobic conditions for 7-10 days. Until now only little literature was available on physiology and metabolic pathway of tea fungus. In this study, we tried to examine the interaction occurred between the yeast and bacteria, followed by investigating the influences of using different combinations of yeast and acetic acid bacteria isolates as starters, and different compounds added on metabolic activity of the tea fungus by using pure cultures. In the study of using different combinations of yeasts and acetic acidbacteria as starters,the Schizosaccharomyces pombe K-2 was found to be better then Pichia membranaefaciens YL-01 in the preparation of the tea fungus. The production of acetic acid was proportional to that of ethanol. The consumption rate of sucrose was also closely related to the viable countof yeast in tea fungus. Glucose, instead of fructose, was preferentially used by the acetic acid bacteria. The metabolism rate of the microorganismsin the tea fungus by using pure cultures combination of S. pomb K-2 with Acetobacter sp. AL-01 and/or Acetobacter sp. AL-02 was higher than that ofusing traditional one, but production of cellulose was lower. It was found that presence of chlorella could enhance the production of acetic acid, ethanol, and gluconic acid in tea fungus prepared by using pure cultures. The enhancement was proportional to the concentration of the chlorella, however, pollen and honey exerted little effect on the production of majorcomponents of the tea fungus. If the pollen or honey (without sterilizationby autoclave) was not added until the tea fungus had fermented for 3 days. This led to the increased metabolic activities of both yeast and acetic acid bacteria, especially productions of both acetic acid and ethanol were markedlyenhanced. However, chlorella exerted little effect on production of major products of the tea fungus. The tea fungus was also prepared by using immobilized yeast and acetic acid bacteria. Both acetic acid and gluconic acid reached their maximum values (2.3 %) after 15 days, while the ethanol reached it''s peak value (1.0%) after 9 days. The flavor of tea fungus prepared by using immobilized cells was much closed to that of using traditional transplanting cultures.
摘要 紅茶菇之微生 物相主要由醋酸菌和酵母菌所組成,兩者共生於紅茶湯液中。紅茶菇成份 包括上層之纖維素薄膜及下層發酵液,後者以醋酸、酒精及葡萄糖酸為主 。傳統上係將部份發酵液及纖維素膜一起移植到一新鮮配製含糖的紅茶湯 液中,於好氣環境下培養7-10天即可飲用。由於目前有相關紅茶菇之生理 及代謝途徑等方面之研究不多,而以純粹培養方式製備紅茶菇的更少見。 本研究以取自紅茶菇之酵母與醋酸菌分離株為菌元,藉由不同菌源組合及 添加不同物質對紅茶菇純粹培養液中主成份變化之影響,探討紅茶菇中酵 母與醋酸菌間之交互作用與代謝之情形。 首先以不同菌源組合進行紅茶 菇發酵試驗,發現酵母Schizo-saccharomyces pombe K-2較Pichia membranaefaciens YL-01適合用於紅茶菇培養;醋酸量的增加與酒精之生 成量成正比之關係。在醣類代謝方面,菌數有關;在葡萄糖與果糖存在下 醋酸菌會優先代謝葡萄糖。以S. pombe K-2搭配Acetobacter sp. AL-01 及Acetobacter sp. AL-02之純粹培養方式製備紅茶菇,其微生物之代謝 速率較傳統移植法快,但其纖維素產量較傳統移植法生產者低。此外,綠 藻添加有助於提高紅茶菇純粹培養液之醋酸、酒精及葡萄糖酸量且添加量 愈高愈明顯,至於添加花粉或蜂蜜之效果不大。蜂蜜或花粉(未經高溫滅 菌過)於接種後第三天添加會有效增加酵母與醋酸菌之代謝活性,尤其在 醋酸和酒精生成量之增加上效果明顯。酵母菌與醋酸菌經固定化可用於製 備紅茶菇,在發酵期間其醋酸、葡萄糖酸及酒精產量之最高值分別為2.3 %、2.3 % 及1.0 %,其風味與傳統移植法相似。
Appears in Collections:食品暨應用生物科技學系



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