Structural, physicochemical, and gel properties of Wencheng yam (Dioscorea alata L.) starch and its application for enhancing set-type yogurt properties

The purpose of this study was to characterize yam starch (YS) and its effect on set-type yogurt (STY) properties. The YS yield was 13.05 ± 1.22 % and it contained 24.6 ± 1.21 % amylose and 75.4 ± 1.21 % amylopectin, which provides gelling and stabilizing properties to the STY. YS significantly improved water-holding capacity (WHC) and reduced syneresis, with the highest WHC (84.9 %) observed in STY fortified with 1.5 % YS after 21 days of storage at 4 ± 2 °C. Moreover, STY with YS showed better microstructure, whereby less fat globule release occurred. The lactic acid bacteria, such as <i>Streptococcus thermophilus</i> and <i>Lactobacillus bulgaricus</i>, were viable in each of the treatments over the storage time, where YS maintained their levels close to 7 log CFU/mL. However, sensory evaluation revealed that the 1.0 % YS fortification achieved the highest overall acceptability score, indicating it is the optimal level for balancing improved physicochemical properties with consumer preference. This indicates that YS not only improves yogurt's physicochemical properties but also improves its shelf life, texture, and sensory attributes.