益生菌发酵剂对于益生菌发酵乳制品的开发与应用有重要意义,本文利用一株具有降低胆固醇作用的益生菌Lactobailluc casei BD-Ⅱ制备发酵剂,研究该菌的生长发酵特性,通过筛选增菌培养基、保护剂及预培养、热激来提高发酵剂存活率和活性。
通过对BD-Ⅱ的生长及发酵特性测定,确定:Lactobailluc casei BD-Ⅱ在复原脱脂乳中10h凝乳,12h pH达到4.5,滴定酸度81.5oT;蛋白分解活力在24h对应游离氨基酸浓度达到29.47ug/ml;最适、最高、最低生长温度分别为38℃、46℃、12℃;药敏实验表明,BD-Ⅱ对四环素、氯霉素和红霉素高度敏感,而对青霉素、氨苄青霉素中度敏感,对链霉素氟哌酸和庆大霉素不敏感。通过气质联用分析该菌发酵乳所含挥发性风味物质酮类物质与各类挥发性脂肪酸总含量分别达到35.91%和52.52%,其中乙酸含量最高,占总挥发性物质质量分数36.26%,2-丁酮和2,3-丁二酮分别占14.18%、10.67%。在0至7d内,BD-Ⅱ发酵乳酸度变化不大,14d时增加至0.96%,有一定程度的后酸化现象;在pH4.0PB...
【英文摘要】
Probiotic starter culture plays important role in developing probiotic yoghurt or fermented dairy products. In this paper,Lactobacillus casei BD-Ⅱ,the cholesterol-reducing probiotic strain,was used to prepared starter culture.The biological and fermentation properties was studied.Enrichment medium and proper protectants were choosen with the means of pre-incubation and heat shock to enhance the surviaval rates and activity.
The biological and fermentation properties of L.casei BD-Ⅱw...