Enhancement effect of kale fiber on physicochemical, rheological and digestive properties of goat yogurt

Abstract

This study incorporated kale fiber into goat milk as a functional component to investigate its impact on the quality and functional characteristics of set goat yogurt. Kale fiber content ranging from 0% to 1.5% (w/v) was added to 15% (w/v) defatted goat milk powder dissolved in water to form set yogurt. The addition of fiber increased the particle size and absolute potential of the goat yogurt, with a positive correlation observed between yogurt hardness, cohesiveness, and fiber content. Optimal water retention and thermal stability were achieved at a 0.5% fiber concentration. Microscopic analysis confirmed the successful incorporation of kale fiber into the yogurt gel network, resulting in significant differences in gel structure based on varying fiber content. Oscillatory temperature scan results indicated enhanced resistance to temperature changes due to the inclusion of kale fiber. Additionally, thixotropy results showed a 10% to 30% increase in gel structure recovery rate compared to the control group. In vitro digestion studies confirmed that kale fiber significantly improved protein bioavailability and release rate during digestion. Thus, incorporating kale fiber into goat milk as a natural plant-based functional component can enhance its nutritional value and rheological properties.