Study On The Fermentation Characteristics Of ?-aminobutyric Acid-producing Lactobacillus Plantarum And Its Application In Functional Yoghurt

In this study,Lactobacillus plantarum 10,which producing GABA,was selected as the research object and the fermentation characteristics and optimal fermentation conditions in skim milk were also researched.Then Streptococcus thermophilus ST962 and Lactobacillus bulgaricus LB 1823 were combined inoculation with Lactobacillus plantarum 10 in skim milk and whole milk separately,finally,a higher content of GABA yogurt is obtained.The main conclusions were as follow:1.the single factor experiments showed that,in skim milk medium,strain 10 had the highest content of GABA when fermentated to 72 h,reached 3.24 g/L;when the fermentation temperature was 35?,the content of GABA was up to 7.68 g/L;when the inoculation amount was 2%,the content of GABA was up to 2.4 g/L;when the adding of L-sodium glutamate was 0.5 ‰,the content of GABA was up to 1.55 g/L.2.the orthogonal experiment of fermentation conditions and different proportion of inoculated strains showed that,the optimal inoculation proportion of strain 10 and strain ST962 was 1:2.5,the content of GABA was up to 0.41 g/L;the optimal inoculation proportion of strain 10 with strain LB 1823 and strain ST962 was 1:1:2.5,the content of GABA was up to 0.57g/L;the optimal fermentation conditions were fermentation time 8 h,fermentation temperature 41 ?.inoculum 4%,L-sodium glutamate 0.5 ‰,and the taste,color and organizational state of yogurt were better,without bad taste.3.the strain 10 and the strain ST962 were mixed and fermented to prepare yogurt,the physicochemical indexes of yogurt in storage period were detected:compared with the traditional fermented yogurt,the hydrolysis activity,the content of GABA in nonfat yogurt and yogurt all increased gradually along with the extension of storage time,to 0.6202 g/L and 0.3824 g/L respectively in the 21st day,increased by 1.763%and 0.703%than the traditional fermented yoghurt.4.the strain 10 and the strain ST962 were mixed and fermented to prepare yogurt,the physicochemical indexes of yogurt in storage period were detected:compared with the traditional fermented yogurt,the content of GABA in nonfat yogurt and yogurt all increased gradually along with the extension of storage time,to 0.6271 g/L and 0.4168 g/L respectively in the 21st day,increased by 2.090%and 0.970%than the traditional fermented yoghurt.