Chiang Mai Journal of Science

Dairy-based yogurt is valued for its nutritional content but raises concerns related to lactose intolerance, cholesterol intake, and environmental sustainability. As a plant-based alternative, soybeans offer high protein content, low cost, and a significantly lower carbon footprint, particularly in Asia where they are abundantly available. In this study, 87 lactic acid bacteria (LAB) strains were isolated and systematically evaluated for their functional properties in soy-based yogurt fermentation—representing one of the most extensive LAB screenings in this context to date. Among them, Lactiplantibacillus pentosus LAB164, Lacticaseibacillus paracasei subsp. tolerans LAB165 and LAB170, and Limosilactobacillus fermentum LAB087 exhibited significantly high β-glucosidase activity, enabling the biotransformation of isoflavone glycosides into bioavailable aglycones, compounds associated with antioxidant and hormone-modulating effects. Lpb. plantarum LAB001 demonstrated the highest γ-aminobutyric acid (GABA) production, highlighting its potential in developing stress-relieving and neuroprotective functional foods. Lsb. fermentum LAB080 and LAB087 also exhibited α-galactosidase activity, which can reduce flatulence-related oligosaccharides and improve digestive comfort. To assess functional performance during fermentation, selected strains were grouped into four experimental combinations and used to ferment soymilk. Three combinations achieved high water-holding capacity (~95%), indicating suitable physical properties for yogurt development. This study presents a diverse and multifunctional LAB resource tailored for soy-based yogurt production. By replacing dairy-based products with optimized plant-based alternatives, this approach contributes to reducing animal product dependency, addressing lactose intolerance, and lowering the carbon footprint of fermented food systems. Our findings offer both nutritional and environmental innovations in the field of sustainable food biotechnology.