Enhancing the texture of fat-free yogurt with leaf-stem extract and casein: Focusing on their softening effect.

Fat-free yogurt often undergoes syneresis because it lacks fat. Although casein prevents syneresis, it induces protein aggregation and lumpy texture. Surfactants are commonly employed to mitigate these quality challenges. Saponins, abundant in by-products like leaves and stems, possess surfactant activity, thereby preventing protein aggregation. In this study, ginseng leaf-stem extract (GE) was assessed to prevent lumpy and grainy yogurt texture. The fermentative, bioactive, physical, and sensory properties of GE-supplemented yogurt were evaluated. GE accelerated yogurt fermentation by promoting the growth of lactic acid bacteria and demonstrated higher antioxidant activity than unsupplemented yogurt. GE stabilized the yogurt matrix, and GE-supplemented yogurt exhibited smaller protein particles and reduced aggregation. Casein-induced lumpy texture was minimized by GE without compromising the syneresis-preventing ability of casein. Sensory evaluation confirmed the soft texture and acceptable taste of the GE-supplemented yogurt. Collectively, GE is a cost-effective surfactant option for improving the texture of fat-free yogurt.