Probiotic drink based on black soybean enriched with double petals butterfly pea flower extract (Clitoria ternatea L.) on physical, chemical, and sensory

This study developed a probiotic black soyghurt drink by fermenting black soybean juice enriched with double petals butterfly pea flower extract (Clitoria ternatea L.) and yoghurt starter cultures. A factorial design (2x2) with Completely Randomized Design and three replications was applied to evaluate the effects of fermentation time (10 and 15 hours) and extract concentration (8% and 13%) on the physical, chemical, and sensory properties of black soyghurt. Results showed that fermentation time and extract concentration significantly influenced viscosity and a* color values, while L* and b* values remained unaffected. Chemically, water, ash, and protein contents were stable across treatments, whereas fat content, pH, total anthocyanin, and antioxidant activity varied significantly, with all parameters meeting SNI 2981:2009 yoghurt standards. Sensory evaluation revealed that taste was affected by fermentation time but not by extract concentration, while consistency influenced ranking but not hedonic tests. The addition of butterfly pea flower extract enhanced anthocyanin content and antioxidant activity, contributing to the functional quality of the probiotic drink. This formulation offers a promising functional beverage alternative based on black soybeans enriched with natural anthocyanin pigments.