Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/50964
標題: 紅茶菇之微生物品質及其製備過程中成份變化之研究
Studies in the Microbiological Quality and Changes in Components During the Preparation of Tea Fungus
作者: 劉碧雲
Liu, Bih-Yun
關鍵字: Tea Fungus;紅茶菇;Acetobacter;Gluconic acid;Candida albicans;醋酸菌;葡萄糖酸;白色念珠菌
出版社: 食品科學系
摘要: 
紅茶菇為一種在含糖之紅茶湯中接種特殊天然菌種,其次於室溫下經
發酵培養一、二星期後而成之家庭自製酸性飲料,其乃由上層之纖維質薄
膜及下層培養液所組成,後者之成份 以醋酸及葡萄糖酸為主。由於紅茶
菇之開放式培養存在著雜菌污染及經長期放置後紅茶菇之再培養易失敗等
問題。本研究乃探討紅茶菇純粹培養之可能性,首先蒐集十二種紅茶菇樣
品,並分離出醋酸菌與酵母菌,後者以Biolog鑑定系統鑑定,發現所有樣
品皆含有好氣性產膜酵母Pichia membranefaciens, 其它如Candida
sorboxylosa, Deddera bruxellensis A,Isatchendia scutulata var.
exigua, Issatchenkia orientalis及Schizosaccharomycespombe 等酵母
則視樣品來源而定,常有兩種或以上共存。十二種樣品於60天的培養期間
酵母菌與醋酸菌菌數略呈下降現象,醋酸菌尤其明顯,酒精在培養至
第14-20 天達最高約0.55-0.6%(v/v) ,醋酸量則於第30天到達最高點
約0.8-1.5g/100ml,而葡萄糖酸則為隨培養時間逐漸上升,第60天時其量
達4-5g/100ml。至於糖類之變化則為在培養末期蔗糖已完全分解,而部份
樣品中葡萄糖仍有殘餘約1.2g/100ml,果糖較高約5-7g/100ml。又由病原
菌白色念珠菌之殘存試驗,知其可在生長速率慢(即產酸速率慢)或於培養
初期時之紅茶樣品中殘存,反之則較不易殘活。 由同步接種酵母菌與
醋酸菌之試驗結果可知S. pombe K-2比Saccharomyces
cerevisiaeCCRC20271 更適合用於紅茶菇之培養;而振盪培養方式可促進
葡萄糖酸,但不利酒精之產生,醋酸量與酒精量成正比例。又蔗糖之消耗
速率亦與酵母菌菌數有關,而酵母比醋酸菌代謝蔗糖之速率較快;在葡萄
糖及果糖共存下,醋酸菌會優先利用葡萄糖。另外,於二階段接種試驗中
,先接種酵母菌雖可提高酒精之產量,但後接種之醋酸菌對酒精之利用效
率不佳。於酵母菌培養期間,碳源消耗速率高,其中又以接菌量高及靜置
培養條件之實驗組最明顯,致使醋酸菌難以利用葡萄糖生產葡萄糖酸,故
若考量主要成份物質之變化,二階段培養方式較不適合紅茶菇之製造。

Tea fungus (or Kombucha) is a home-brewed beverage which is
prepared by fermenting the sugar added in the black tea
decoction with a specific, butnaturally occurring starter. Tea
fungus is composed of two portions, a floatingcellulosic
pellicle layer and the sour liquid broth. Both acetic acid and
gluconic acids are the major ingredients found in the liquid
broth. The fermentation is usually carried out under
uncontrolled conditions, so the contamination of acid-tolerant
pathogenic microorganisms is poddible. Besides,it is difficult
to obtain an active and safe tea fungus if the starter was an
old one. It is therefore to investigate the feasibility of
preparing the teafungus by rsing pure cultures in this study.
Acetic acid bacteria and yeast flora were isolated, and some
were identified further, from 12 collections oftea fungi. The
Pichia mimbranefaciens, a film-forming yeast, was isolated
fromall the samples while other yeasts including Candida
sorbrxylosa, Dekkera bruxellensis A, Issatchenkia scutulata var.
exigua, Issatchenkia orientalis,and Schizosaccharomyces pombe
were present either two or three of them occasionally, depending
upon the sources of tea fungi. The viable counts of
microorganisms, particularly for acetic acid bacteria, decreased
graduallyduring a cultivation period of 60 days. The ethanol
content reached it''smaximum values (0.55-0.6%,v/v) after 14-20
days while the acetic acid reaches it''s maximum values
(0.8-1.5g/100ml) after 30 days. The gluconic acid content
increased with time and reached 4-5g/100ml after 60 days. The
sucrose was usedup, and the respective residual glucose and
fructose contents for some samples were about 1.2g/100ml and
5-7g/100ml at the end of fermintation. The curvivalcurves of a
pathogenic Candida albicans inoculated to tea fungi at various
growth stages were also studied. The results indicated that C.
albicans could survive from the acidic environment produced by
the tea fungus having a lower growth rate or acid production
rate during the early stage of fermentation;however, it died
rapisly if the tea fungus was an actively growing one. In the
study of co-inoculating a yeast with an acetic acid bacterium,
the S. pombe K-2 was found to be better than S, cerevisiae CCRC
20271 in the preparation of the tea fungus. The shaking culture
stimulated the production ofthe gluconic acid, but not for
ethanol, The consumption rate of sucrose was also closely
related to the viable count of yeast in tea fungus, and
sucroseconsumption rate by the yeast was faster than that of
acetic acid bacteria.Glucose, instead of fructose, was
preferentially used by the acetic acid bacteria. However, the
alcohol content increased initially in a two-stage cultivation
process, i.e. S. pombe K-2 was inoculated in advance and
cultivated for 5 days, but the subsequent acetic acid bacterium
failed to convert the alcohol produced efficiently in the sceond
stage. Besides, the carbon source was consumed rapidly by the
yeast, especially if large inoculum size and staticculture were
used. Consequently, the residual glucose concentration in the
teafungus was too low for the acetic acid bacterium to produce a
significant amountof gluconic acid. Finally, the current two-
stage cultivation process is not recommended for preparing the
tea fungus due to its less efficient production ofmajor
ingredients such as gluconic acid.
URI: http://hdl.handle.net/11455/50964
Appears in Collections:食品暨應用生物科技學系

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