Fermentation characteristics and inhibitory effect of brown rice vinegar on adipocyte differentiation in 3T3-L1 cells

The brown rice vinegar was prepared by adding 10% of vinegar starter, and incubated using the strain Acetobacter pasteurianus JBA172705. The alcohol concentration of brown rice liquor was adjusted to 6%, and seed vinegar was added to 10%. Then, it was cultured by shaking for 16 days (30°C, 120 rpm). After fermentation, brown rice vinegar was extracted with 70% ethanol to evaluate the anti-obesity effect using 3T3-L1 adipocyte cells. The total acidity of brown rice vinegar increased to 6.43% after 16 days of fermentation, and acetic acid increased 15 times and succinic acid 2.5 times or more. The total phenolics and free amino acid contents decreased during the acetic acid fermentation period, and were 48.53 mg GAE/mL and 18.79 mg% (w/v) at the 16th day of fermentation. At a concentration of 100 μg/mL of brown rice vineagar extract (BRV 16d), the lipid accumulation rate was 72.2%. The leptin expression level was reduced by more than 50% according to the treatment of brown rice vinegar extract. It was confirmed that the PPARγ and SREBP-1c expression levels decreased at a concentration of 100 μg/mL. As a result, brown rice vinegar is expected to be effective in anti-obesity by suppressing the expression of transcription factors that induce obesity.