Optimization of GABA-enriched fermented meat using lactic acid bacteria and response surface methodology: <i>Nem chua</i> as a case study

This study aimed to optimize the fermentation of nem chua, a traditional Vietnamese fermented meat, to enhance γ-aminobutyric acid (GABA) production using lactic acid bacteria (LAB) starter cultures. A Box-Behnken design was applied to evaluate the effects of monosodium glutamate (MSG), pyridoxal 5’-phosphate (PLP), and temperature on GABA biosynthesis. The optimal condition (1.0% MSG, 0.01% PLP, 37 °C) achieved a GABA yield of 4.705 mg/g, with strong agreement between predicted and experimental values (R2 = 0.8282). LAB inoculation significantly influenced pH reduction, lactic acid production, and proteolysis, confirming the effectiveness of controlled fermentation. Comparative analysis showed that the optimized GABA concentration exceeded values reported for fermented sausages and was comparable to LAB-fermented dairy and vegetable systems, underscoring its broader applicability. This study highlights nem chua as a model for developing functional fermented meats enriched in bioactive compounds, aligning with global trends toward health-oriented diets.