Effects of mashed potato on techno-functional characteristics of set hybrid yogurt

The study aimed to prepare the yogurt with different levels (0, 10, 25, and 50% w/w) of mashed potato (MP) according to whole milk powder and investigate the techno-functional characteristics after 24 h of storage at 4 °C. The acidity of yogurt was increased and pH was decreased with increased MP from 0 to 50%, due to acid production of lactic acid bacteria during fermentation. In comparison, the syneresis was decreased (5.80-4.89%) with increased MP. The average particle size increased from 36.82 to 103.74 μm, which might be intermolecular aggregation caused by the interaction between MP and casein. The hardness was decreased (147.84-127.54 g) and the adhesiveness (- 508.60 to - 342.63 g s). The apparent viscosity of yogurt showed a downward trend with increasing MP. The results showed by LF-NMR that as the MP content increased, the relaxation time of the two peaks of the yogurt moisture distribution map increased, indicating that with increased MP the ability to movement of water in the gel was increased. The most appropriate particle size of yogurt sample with 25% MP improved texture while homogenous aggregates improves the stability of yogurt that enhance applications of MP in fermented dairy industry.