Isolation and Identification of Lactic Acid Bacteria from Fermented Soybean Pulp and Its Application as Starter Culture for Soy Yogur

Food waste processing holds great potential in mitigating global food insecurity. Valorization of food waste is a sustainable practice that also lessens the effects of climate change. Isolation, identification, and characterization of lactic acid bacteria from fermented soya pulp was conducted. The isolated lactic acid bacteria species was utilized as starter culture to produce soy yogurt. This study was performed to identify LAB isolated from fermented soya pulp using 16s rRNA gene sequencing; to ferment soymilk using the LAB isolated from fermented soya pulp and develop soy yogurt; to determine the proximate nutritional composition of the soy yogurt through proximate analysis; and to evaluate the sensory characteristics of the yogurt such as color, aroma, texture, taste, and overall acceptability. The 16s rRNA gene sequencing procedure identified the isolated lactic acid bacteria species as Pediococcus pentosaceus Mees, 1934. Four yogurt samples were formulated using P. pentosaceus and a commercial starter culture. Proximate compositions such as titratable acidity, ash content, crude protein, and crude fat were determined. The soy-based yogurt drinks were similarly high in protein compared with the cow’s milk counterpart. Notably, formulation 1 with the P. pentosaceus as the sole starter culture scored highest in crude protein. Significant difference in the average ash content between the four samples was observed. Post-hoc analyses using the Bonferroni correction revealed that formulation 1 with the isolated starter culture, P. pentosaceus, had the highest ash content. Sensory evaluation revealed that formulation 2 with both the isolated starter culture and commercial starter gained peak in color, taste, and overall acceptability. There was significant difference in the average aroma and texture scores between the four samples, favoring the cow’s milk yogurt sample for the aroma and the soymilk yogurt with both P. pentosaceus and commercial starter culture for the texture. This study showed the potential of P. pentosaceus as a sole starter culture and in combination with commercial starter culture in producing functional foods from food waste such as soymilk-based yogurt. Refinement and standardization of the yogurt production protocol is recommended to produce the yogurt with better texture and taste. By so doing, product development from food waste can support sustainable food production and mitigate global food insecurity and climate change.