Development of Probiotic Soy Yogurt Containing Kale Powder: Evaluation of Functional and Plant-Based Properties

บทคัดย่อ

: Probiotic soy yogurt containing kale powder represents a promising plant-based functional product suitable for lactose-intolerant individuals and health-conscious consumers. This study aimed to develop and characterize soy-based probiotic yogurts containing kale powder at concentrations of 0%, 1%, 3%, and 5% (w/w). All formulations were standardized to an initial total soluble solids (TSS) content of 15 °Brix and fermented at 43 ± 1 °C for 8 hours using a commercial yogurt starter and probiotic culture. The yogurt containing 1% kale powder exhibited the most desirable physicochemical and functional properties, including favorable fermentation characteristics (pH 4.63, titratable acidity 0.75 ± 0.03%), the highest viable lactic acid bacteria (LAB) count (8.37 ± 0.05 log CFU/g), and optimal curd structure. Sensory evaluation using a 9-point hedonic scale with thirty untrained panelists confirmed its highest overall acceptability (7.93 ± 0.74). Chemical composition analysis revealed slight variations among formulations, with the 1% kale-containing yogurt showing relatively higher levels of protein (3.49 g/100 g), dietary fiber (0.95 g/100 g), carbohydrate (10.6 g/100 g), energy (65.6 Cal/100 g), and vitamin K₁ (4.94 µg/100 g), reflecting the natural contribution of kale powder rather than fortification. During 21 days of storage at 4 ± 1 °C, the 1% kale-containing yogurt maintained probiotic viability above 7.0  log CFU/g, consistent with internationally recognized efficacy criteria for probiotic products. No yeast and mold growth was detected during storage. These findings highlight, for the first time, the feasibility of formulating probiotic soy yogurt containing kale powder with desirable product quality and functional potential, aligning with current trends in plant-based fermented foods.