摘要
酸乳在储藏、销售直至食用前,由于乳酸菌仍会生长繁殖,使pH值继续下降,出现消费者不可接受的过酸味及感官质量下降等后酸化现象。针对这一问题,以市售酸乳中的乳酸菌为研究对象,先分离和筛选得到纯化菌株,通过发酵酸度和pH值筛选出9号乳酸菌作为诱变的出发菌株,再经过紫外、DES单因素诱变和UV+DES复合诱变以及青霉素处理等条件筛选出突变菌株F504,其诱变的最佳条件是UV+DES复合诱变:UV 1 min、1.5%DES。在42℃下诱变后菌株发酵酸乳8 h后酸度值比出发菌减少了14.5%。在10℃下贮藏时,10 d后突变菌株F504的酸度值比出发菌株9号菌株减少了13.1%,且F504菌株比9号菌发生后酸化的时间推迟了2 d。
Yogurt before storage, sale and consumption, due to the growth of lactic acid bacteria will multiply, the p H continues to decline, so it appear some phenomenon that consumers unaccept too sour and other sensory quality of acidifi cation. To solve this problem, this study mainly takes the lactic acid bacteria in yogurt as the research object. Purifi cation lactic acid bacteria strains NO.9 was isolated and screened by fermentation acid production ability and pH. After UV, DES single mutagenesis, UV＋DES complex mutagenesis and penicillin treatment, the F504 strain was screened out. The best conditions is UV＋DES. The compound mutation is UV 1 min, 1.5% DES. After 8 h mutagenesis strain acidity than the starting yogurt bacteria reduced by 14.5% at 42 ℃. When stored at 10 ℃, after 10 d mutant strains F504 acidity than the starting strain reduced by 13.1% and after acidification of F504 strains was delayed two days than the NO.9.
出处
《食品科技》
CAS
北大核心
2014年第12期38-42,共5页
Food Science and Technology
关键词
乳酸菌
后酸化
紫外线
硫酸二乙酯
诱变
lactic acid bacteria
after acidifi cation
ultraviolet ray
diethyl sulfate
mutagenesis
