Enhanced production of gamma-aminobutyric acid (GABA) in Mang Buk Brown rice via optimal fermentation conditions with Lactobacillus brevis, Lactobacillus pentosus, and Lactobacillus plantarum

Gamma-aminobutyric acid (GABA) is a biologically active amino acid with numerous health benefits. This study aimed to optimize the production of GABA-enriched Mang Buk brown rice through fermentation with various Lactobacillus strains. The impact of incubation temperature, duration, pH levels, and Lactobacillus concentration on GABA content were systematically investigated. The results revealed that in the presence of Lactobacillus brevis under specific conditions, GABA concentrations significantly increased to 8.16 mg/100gDW. Additionally, the condition of 35 °C and 30h of incubation consistently resulted in the highest GABA content across different Lactobacillus strains. However, the increase in the concentration of Lactobacillus involved in the fermentation process led to a rapid decline in GABA content. Simultaneously, the most suitable operating environment for yeast was determined to be at a pH range of 5–6. After fermentation under optimal conditions, the GABA content reached 24.01 mg/100g DW, representing a 141.24-fold increase compared to the initial content. These results were validated using the high-performance liquid chromatography (HPLC) method. These findings highlight the potential for tailored fermentation strategies to produce nutritionally rich GABA-enriched rice products with promising health benefits. The optimized process presents an opportunity for expanding the production of functional foods with enhanced nutritional value. • GABA content in Mang Buk rice increased from 0.13 to 24.01 mg/100g DW (141.24-fold). • Fermentation with L. brevis at pH 5, 35 °C, and 30h achieved the highest GABA yield. • L. pentosus showed optimal GABA biosynthesis at pH 6, reaching 8.33 mg/100g DW. • Excessively high or low concentrations of Lactobacillus negatively affect GABA content.