硫酸二乙酯诱变选育乳酸菌菌株的研究

Study on breeding of Lactobacillus strain by diethyl sulfate mutagenesis

为改进酸奶的储藏质量,延长货架期,从酸奶发酵剂入手研究了硫酸二乙酯(DES)诱变乳酸菌的参数,以期选育出抗酸奶后酸化的菌株,从而延长酸奶的保质期。在前期预试验的基础上采用均匀设计试验方案,确定DES浓度、诱变时间、诱变温度的最佳工艺参数。结果表明:影响致死率的因素大小顺序:DES浓度>诱变温度>诱变时间;DES诱变的最佳条件:DES质量分数为0.7%,诱变时间为30min,诱变温度为37℃。筛选得到的突变菌株N01#,在37℃贮藏时产乳酸量与出发菌株一样,而在10℃贮藏时,产乳酸量明显减少;贮藏期与对照相比延长了3d。物性指标(硬度、弹性、黏附性)测定显示良好。

In order to keep sensory quality and increase shelf life of yogurt, the optimum conditions of Lactobadllus were mutated by diethyl sulfate （DES） has been studied. The purpose of the research was to breeding new strain of anti-postacidification in yogurt.Uniform design experirnent was used to determined the technology parameters of concentration of DES, mutation time and mutation temperature. The results show the optimum conditions： DES concentration, mutation time and mutation temperature were 1.0%, 30rain and 40 ℃, respectively. Acidproduced of the breeding strain N01^# was same to original strain at 37 ℃, but lower obviously than original strain at 10 ℃. The storage period of yogurt sample had been delayed for 3 days. Physical index graph of yoghurt shows well.