Gamma-aminobutyric acid production in traditional African fermented foods and its potential for functional food development

Traditional African fermented foods are integral to food security, nutrition, and cultural heritage across the continent. Beyond their roles in preservation and sensory enhancement, these foods represent promising sources of bioactive compounds with potential health-promoting properties. Among these compounds, γ-aminobutyric acid (GABA), a non-protein amino acid produced primarily by lactic acid bacteria, Bacillus species, and selected yeasts during fermentation, has attracted considerable attention because of its diverse physiological functions. Evidence from in vitro, animal, and human studies suggests that GABA may contribute to neuroprotection, blood pressure regulation, glucose homeostasis, stress reduction, sleep improvement, and immune modulation. This review critically examines the biosynthesis, physiological roles, health benefits, and microbial production of GABA, with particular emphasis on traditional African fermented foods. Reported GABA concentrations vary widely depending on microbial strains, substrates, and fermentation conditions, ranging from approximately 20 mg/kg in spontaneous cereal fermentations to over 7.5 g/L in optimized microbial fermentation systems. While substantial progress has been made in the development of GABA-enriched Asian fermented foods such as kimchi, miso, and fermented dairy products, the GABA-producing potential of African fermented foods remains largely underexplored despite their rich microbial diversity and abundance of indigenous fermentation substrates. Current challenges include limited characterization of GABA-producing microorganisms, lack of standardized fermentation processes, inadequate safety and clinical evaluations, and constraints associated with industrial-scale production. Emerging strategies, including co-culture fermentation, stress-induced bioprocessing, metabolic engineering, and the application of indigenous starter cultures, offer promising opportunities for enhancing GABA production. Integrating traditional African fermentation knowledge with modern biotechnological approaches could facilitate the development of culturally relevant functional foods and contribute to improved public health, food security, and sustainable food system development.