Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/51139
標題: 不同乾燥方法對添加各種保護劑之Lactobacillus casei CCRC 14023菌株貯藏效果的探討
Studies of the Variation of the Stored Lactobacillus casei CCRC 14023 Treated with Different Protective agents and Drying Methods
作者: 蘇家俊
Su, Chia-Chun
關鍵字: Lactobacillus casei;Lactobacillus casei;β-galactosidase;freeze-drying;vacuum-drying;nonfat dry milk solids;maltodextrin;trehalose;storage;β-galactosidase;冷凍乾燥;真空乾燥;脫脂乳粉;麥芽糊精;海藻糖;貯藏
出版社: 食品科學系
摘要: 
由於Lactobacillus casei能在發酵過程中產生特殊之風味,因此在乳品工業中之應用非常廣泛。而為了便於工業上的應用一般皆以乾燥的方式來保存菌體,但由於乾燥方式及貯藏條件等因子,皆會對菌體造成不同的傷害而影響菌體在貯藏過程中的存活率,故常添加保護劑以減少菌體在乾燥及貯藏時的傷害,但不同之菌株其最適保護劑種類及最適之濃度亦不同。因此本實驗之目的即在探討不同濃度之不同保護劑、貯藏溫度及處理方式對L. casei存活率及貯藏期間保存穩定性之影響,並希望藉由乾燥菌株對氯化鈉和膽鹽之敏感性,以及乾燥菌株之β-galactosidase活性變化來探討各保護劑對L. casei之保護作用。
結果顯示菌體在高溫(25℃)貯藏時的存活率較低,而各保護劑之最佳濃度皆為10%而非15%。在低溫(-40℃)貯藏時三種保護劑的存活率並無顯著差異性,但以10%脫脂乳粉為保護劑時即使在貯藏溫度較高(4℃)的狀態下,乾燥菌體在貯藏期間的存活率依然與低溫(-40℃)下貯藏者差不多,而添加麥芽糊精及海藻糖者即有顯著的下降。而由菌株對氯化鈉及膽鹽的敏感性發現,乾燥對菌體細胞膜之傷害較細胞壁大,而真空乾燥對菌株的傷害又較冷凍乾燥大。另一方面,由所得結果亦發現雖然在低溫(-40℃)貯藏期間,而添加脫脂乳粉對細胞膜之保護效果較麥芽糊精及海藻糖差,但三者在貯藏期間之存活率並無顯著差異性存在,推測脫脂乳粉在貯藏期間保護L. casei菌體細胞膜的作用並不大。此外,藉由β-galactosidase的活性變化雖然可以看出不同乾燥方式對細胞膜的傷害差異,但其並不是一個判別不同保護劑間之保護效果的良好指標。
關鍵字:Lactobacillus casei、β-galactosidase、冷凍乾燥、真空乾燥、脫脂乳粉、麥芽糊精、海藻糖、貯藏

Lactobacillus casei was applied in the dairy industry extensively because of the special flavor produced with the process of its fermentation. According to the convenience of industrial application, dehydration is a popular way to preserve bacteria cells. Due to the survival of cells changed with factors which cause damage to cells based on the dehydration and storage conditions, protective agents were added to decrease the damage of cells during dehydration and storage. In addition, the effects of protective agents and their concentrations were varied with different species of bacteria. Therefore, the purpose of this study was to compare the effect of different concentrations of various protective agents, storage temperatures and processing treatments on the survival of L. casei and its storage stability during storage, and try to find out their protective effects by the sensitivity of dried cells to sodium chloride and oxgall and the change of β-galactosidase activity in dried cells.
Results showed that the survival of cells was lower at higher storage temperature (25℃) and the best concentration of those tested protective agents were all at 10% instead of 15%. At low storage temperature (-40℃), there was no significant difference among the survival of dried cells with three kinds of protective agents. There was significant difference between the survival of dried cells with 10% nonfat dry milk solids (NFDMS) at higher storage temperature (4℃) and that at lower storage temperature (-40℃) during storage, but there was a significant decrease in the survival of dried cells with maltodextrin (MD) and trehalose at higher storage temperature (4℃) compared to that at lower storage temperature (-40℃). It was found that the damage on cytomembrane was more seriously than that on cell wall caused by drying, and the damage from vacuum-drying was more seriously than that from freeze-drying based on the sensitivity of dried cells to sodium chloride and oxgall. Although the protection of NFDMS was worse than MD and trehalose to dried cells' cytomembrane during storage at low storage temperature (-40℃), there was no significant difference among the survival of dried cells with three kinds of protective agents. Therefore, it was suggested that the protection of NFDMS to dried L. casei's cytomembrane was not good during storage. Although it could be found that the difference of damage to cytomembrane among different drying treatments caused by the change of β-galactosidase activity, it was not a good indicator to compare the protection effect among different protective agents.
Keywords: Lactobacillus casei, β-galactosidase, freeze-drying, vacuum-drying, nonfat dry milk solids, maltodextrin, trehalose, storage
URI: http://hdl.handle.net/11455/51139
Appears in Collections:食品暨應用生物科技學系

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