冷冻和冻干过程对保加利亚乳杆菌存活性影响的研究  

Effects of Freezing and Freeze-drying on the Viability of Lactobacillus delbrueckii subsp.bulgaricus

作　　者：万红兵[1] 田洪涛[1] 种克[1] 李雅乾[1] 李宁[1] 翟硕莉[1] 

机构地区：[1]河北农业大学食品科技学院,河北保定071000

出　　处：《现代食品科技》2006年第4期1-3,12,共4页Modern Food Science and Technology

基　　金：河北省"十五"科技攻关专项专题:优良菌种选育及高效发酵剂的研制(编号03220171D)

摘　　要：研究了预冻过程中冷冻温度、冷冻时间以及升华干燥过程中发酵剂含水量对保加利亚乳杆菌(Lactobacillusdelbrueckiisubsp.bulgaricus)L.b-S1细胞存活率的影响。结果表明:-20～-18℃和-40～-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);干燥过程中,发酵剂含水量对细胞干燥存活率影响显著(P<0.05),但存活率降低程度因含水量下降水平不同而出现差异,其中以含水量由40%左右至5%左右的过程影响最大,细胞存活率由88.68%降至40.11%,下降约50%左右,差异显著(P<0.05)。本研究为研制开发高效浓缩型直投式酸奶冻干发酵剂,合理调控冻干工艺提供指导依据。The effects of frozen time, temperature and the water content of starter in the freeze-drying process on the viability of Lactobacillus delbrueckii subsp.bulgaricus L.b-Sl were studied. The results showed that, within the ranges from -20℃ to -18℃ and from -40 ℃to -35 ℃, frozen temperatures had little effect on the viability of strain L.b-SI（P〉O.05）. From the start-point till the end-point of freezing, the difference of the viability of strain Lb-S1I was significant （P〈0.05）. However, after the culture of strain L.b-S1 was fully frozen, no significant loss in the viability was found following the extension of frozen time （P〉0.05）. In the freeze-drying process, the water content of starter showed marked effect on the viability of strain L.b-S 1 （P〈0.05）. The different depressed level of the water content of starter resulted in different reduced degree of the viability ratio of strain L.b-S I. When the water content of starter was decreased from 40% to 5%, the viability ratio of strain L.b -SI was decreased from 88.68% to 40.11%, so the different of viability was very significant （about 50%）. This study will provide the evidence for the development of high effective lyophilized lactic acid direct vat starter and for reasonable regulation of freeze-drying techniques.

关 键 词：保加利亚乳杆菌 真空冷冻干燥 冷冻时间 冷冻温度 发酵剂含水量 存活率 

分 类 号：TS252.1[轻工技术与工程—农产品加工及贮藏工程]