Streptococcus thermophilus producing γ-aminobutyric acid and application thereof

A preparation method of a γ-aminobutyric acid-containing dairy product, comprising:

• (a) activating a γ-aminobutyric acid-producing Streptococcus thermophilus strain:
• inoculating γ-aminobutyric acid-producing Streptococcus thermophilus in a de Man, Rogosa, Sharpe (MRS) liquid medium and culturing the γ-aminobutyric acid-producing Streptococcus thermophilus strain at 37° C. to 45° C. for 12-24 h;
• (b) preparing a fermentation agent:
• inoculating and culturing the γ-aminobutyric acid-producing Streptococcus thermophilus strain after activating in a sterilization skim milk medium to obtain the fermentation agent;
• wherein the inoculating is conducted at a volume of 2%-5%;
• and a mass fraction of skim milk powder in the skim milk medium is 10%-15%;
• (c) preparing a fermentation base:
• mixing raw materials, hydration, homogenization, and sterilization to obtain the fermentation base;
• wherein a raw material of the fermentation base comprises any one of raw milk, whole milk powder, white sugar, sodium glutamate, glucose, light cream, a stabilizer, whey protein powder, or a thickening agent or a combination of at least two selected therefrom;
• and
• (d) conducting inoculation and fermentation:
• inoculating the fermentation agent to the fermentation base, and conducting inoculation and fermentation at 37° C. to 43° C. for 24-48 h;
• wherein an inoculation volume of the fermentation agent during the inoculation and fermentation is 1.58-6%;
• wherein the γ-Aminobutyric acid-producing Streptococcus thermophilus is named Streptococcus thermophilus ST36 and deposited in the China General Microbiological Culture Collection Center on Sep. 18, 2020, with deposit No. CGMCC NO.20676;
• and
• wherein a 16S rDNA sequence of the γ-Aminobutyric acid-producing Streptococcus thermophilus is as shown in SEQ ID No.