摘要
研究了冷冻温度、冷冻时间、基质ｐＨ以及培养基组成、培养温度、菌龄对两歧双歧杆菌在冷冻乳中存活率的影响。结果表明：－２０℃与－３５℃冷冻对细胞存活率无显著影响（Ｐ＞０．０５）；冷冻起始至完全冻结，细胞存活率差异显著（Ｐ＜０．０５），而冻结后细胞存活率并不随冷冻时间延长而存在显著差异（Ｐ＞０．０５）。冷冻基质最适ｐＨ值为５．５～８．０；培养基组成中，吐温８０、甘油、蛋白陈、酵母粉可极显著提高细胞抗冷冻性（Ｐ＜０．０１）。进一步采用正交试验筛选出抗冷冻培养基（Ｍ_ＧＣ）。３２℃较３７℃培养的菌体细胞的抗冷冻性略有增强，而统计分析差异不显著（Ｐ＞ ０．０５）；细胞最佳收获菌龄为对数后期或稳定初期。本文还对细胞抗冷冻性进行了初步探讨。
Freezing temperature, freezing time, medium pH,and medium constitutants,cultivation temperature,and cell ape, these factors were studied so as to disclose their effects on the survival rate of Bif idobacterium bifidum (Bb) in frozen milk. The results indicated that freezing temperatare at - 20t, or - 35℃ did not exert influences on cell survival rate significantly (P > 0.05); Cell survival rates of samples appear noteworthy difference from initial freezing to complete freezing (P < 0.05), and cell survival rates did not appear noteworthy difference as freezing time was lengthened (P> 0.05); Optimal pH of frozen medium was from 5.5 to 8.0; some medium constitutants enforced markedly freezing-resistance of cells, for example, Tween 80, glycerine, pepton, yeast extract (P < 0.01); Furthermore, freezing-resistance medial (M_GC)was screened by orthogonal experiment; freezing resistance of Bacterial cells was slightly stronger at cultivation temperature, 32℃than 37℃, and difference of statistical analysis was not significant (P> 0.05): Optimal cell ape of harvesting was in later log phase or initial stationary phase.Finally, cell freezing-resistance was initially discussed in the article.
出处
《微生物学通报》
CAS
CSCD
北大核心
2000年第2期115-119,共5页
Microbiology China
关键词
双歧杆菌
冷冻乳
存活率
抗冷冻性
Bifidobacterium bifidum,Frozen milk,Survival rate, Freezing-resistance
