Enhanced production of γ-aminobutyric acid in litchi juice fermented by Lactobacillus plantarum HU-C2W

Abstract

The lactic acid bacteria (LAB) strain isolated from traditional Chinese kimchi was used as a starter culture to enhance the production of γ-aminobutyric acid (GABA) in fermented litchi juice. The GABA-producing abilities of the isolated strains were analyzed using HPLC and identified by 16 S rRNA sequences analysis. The safety of selected strain was evaluated by acute oral toxicity testing in KM mice in vivo. Results indicated that the isolated strain named HU-C2W with the highest GABA-producing ability was identified as Lactobacillus plantarum and produced 3.92 g/L of GABA in an artificial medium. This strain exhibited high resistance to artificial gastric conditions in vitro. The litchi juice fermented by Lactobacillus plantarum HU-C2W at 37 °C for 40 h, was observed to have a high GABA content of 134 mg/100 mL, and a 27% reduction in total carbohydrates. Addition of carbon and nitrogen sources did not elicit further significant changes in the fermented litchi juice. Ultimately, the natural litchi juice has been shown to be a suitable substrate for lactic acid fermentation. The results suggest that Lactobacillus plantarum HU-C2W has potential to be applied as a GABA-producing probiotic starter culture for the development of functional fermented litchi juice, offering a way of replacing chemical GABA by natural GABA.