Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/51794
標題: 固定化乳酸菌香蕉發酵的研究
Fermentation of Banana by Immobilized Lactic Acid Bacteria
作者: 曾政鴻
Tsen, Jen-Horng
關鍵字: Banana
香蕉
Lactobacillus acidophilus
Cell immobilization
Fermentation
Probiotic
Prebiotic
Fructooligosaccharides
Synbiotic
嗜酸乳酸桿菌
細胞固定化
發酵
益生菌
益菌物質
果寡醣
合生素
出版社: 食品科學系
摘要: 本研究使用香蕉作為原料來製備培養基,進行嗜酸乳酸桿菌的發 酵,並分別利用褐藻酸鈣及κ-紅藻膠凝膠所製備得之膠球來進行細胞 的包埋固定化,所得褐藻膠膠球之直徑約2.6 mm,κ-紅藻膠膠球直徑 約為3.0 mm,以嘗試提升嗜酸乳酸桿菌在香蕉培養基中的發酵效率。 所用香蕉原料包括綠香蕉及成熟香蕉,分別利用固定化及游離態菌體 來進行發酵80小時。在發酵過程中,不論是固定化或是游離態的嗜酸 乳酸桿菌發酵,成熟香蕉培養基中的活菌數均高於綠香蕉培養基。在 固定化菌體的發酵生長過程中,部份菌體會自包埋的膠球中脫離進入 培養基溶液中生長。在固定化菌體發酵實驗部份,培養基懸浮液中的 最終活菌數可達105 CFU/ml的程度,固定化膠球中的活菌體濃度可達 108 CFU/ml gel以上;而在游離態發酵組中,最終活菌為106 CFU/ml 的程度。固定化菌體能克服綠香蕉培養基中的不利條件,呈現出較佳 的生長。在發酵過程中,pH值與可滴定酸度的變化和菌株的生長情況 有明顯的關聯。成熟香蕉培養基經固定化嗜酸乳酸桿菌發酵後,其中 果寡醣的含量變化不大,可作為嗜酸乳酸桿菌之益菌物質,具有成為 良好synbiotics產品之潛力,其中褐藻酸鈣固定化者又優於κ-紅藻膠 固定化者。由成本分析的整體結果發現,褐藻酸鈣固定化要優於κ-紅 藻膠固定化。另一方面,將嗜酸乳酸桿菌分別以褐藻酸鈣及κ-紅藻膠 進行固定化,探討細胞固定化對菌體凍結及冷凍乾燥時存活的保護效 果,以及其對冷凍乾燥菌體在5℃、25℃、45℃、60℃、70℃等不同溫 度下之貯藏安定性的影響。實驗所用游離態及固定化菌體的初始濃度 均達1010 cells/ml層次的程度,結果發現褐藻酸鈣與κ-紅藻膠膠球的 固定化均能有效地提供保護效果,減少菌株在操作過程中所受到的傷 害。在所用的不同貯藏溫度下,不論是游離態或是固定化的菌體,其 Log D值與貯藏溫度間均具有極高的相關性,而由此二種狀態菌體所得 之二條Log D與貯藏溫度的迴歸直線所求出之z值間亦具顯著差異(p < 0.05),顯示細胞固定化能增加冷凍乾燥菌體在貯藏過程中對溫度的耐 受性,並且能減低溫度變化對冷凍乾燥菌體貯藏安定性的影響。
Banana was used as the raw material for the preparation of fermentation media of Lactobacillus acidophilus, and cell immobilization was applied to improve the fermentation efficiency of L. acidophilus in banana media. Cell immobilization was performed using calcium alginate and κ-carrageenan as the entrapping matrix, and gel beads of diameters around 2.6 mm for the former and 3.0 mm for the latter were obtained. Both green and ripe bananas were used for the preparation of banana media, and both free and immobilized cells were used to conduct the fermentation for 80 hours. The viable cell number in ripe banana media was found to be higher than that in green ones during both free cell and immobilized cell fermentation. During the fermentation of immobilized cell, cells would leak out from the gel beads and grew in the medium solution. In immobilized cell fermentation, the final viable cell number could reach 105 CFU/ml in medium suspension and that in gel beads could become over 108 CFU/ml gel. In free cell fermentation, the final viable cell number was around 106 CFU/ml. Immobilized cell could overcome the unfavorable conditions in green banana media and improved results could be obtained. During the fermentation, the variation of pH and titratable acidity showed obvious relationships with the growth of cells. Variation of fructooligosaccharides contents in ripe banana media was not remarkable in immobilized cell fermentation compared to free cell. Immobilized L. acidophilus fermented banana medium was able to be used as a synbiotic product by combining the probiotic effect of L. acidophilus and the prebiotic effect of banana. The effect of Ca-alginate immobilization was better than κ-carrageenan. Based on the overall results of cost analysis, Ca-alginate immobilization was a better choice compared toκ-carrageenan immobilization. On the other hand, L. acidophilus was immobilized using Ca-alginate andκ-carrageenan, and protection effects of cell immobilization on the viability of the bacteria after freezing and freeze-drying were studied, and its influence on the storage stability of the freeze-dried cells at 5℃, 25℃, 45℃, 60℃, 70℃ was also investigated. Initial concentration of both free and immobilized cells used for experiments all reached the level of 1010 cells/ml. Results indicated that the immobilization in Ca-alginate gel beads andκ-carrageenan gel beads could provide effective protection to reduce the damage of bacteria under operations. High correlations were obtained between Log D values and storage temperatures for both free and immobilized cells under those various storage temperatures used. the z value which derived from the linear regression equation of Log D and storage temperature for free and immobilized cells were significantly different (p < 0.05). Cell immobilization could enhance temperature tolerance of the freeze-dried bacteria during storage and diminish the influence of temperature variation on the storage stability of freeze-dried cells.
URI: http://hdl.handle.net/11455/51794
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