Yogurt Fortification with Green Papaya Powder and Banana Resistant Starch: Effects on the Physicochemical and Bioactive Properties.

Functional yogurts from partially skimmed milk with banana resistant starch (BRS) and green papaya powder (GPP) were prepared for added nutritional and health benefits. A total of 5 set-type yogurt groups were prepared following conventional process: (1) milk only- control, (2) milk + 1 (BRS) :1 (GPP), (3) milk + 1 (BRS) :2 (GPP), (4) milk + 2 (BRS) :1 (GPP), and (5) milk + 3 (BRS): 1 (GPP). To evaluate the effect of the supplementation with BRS and GPP on yogurt quality, physicochemical, microbiological, and bioactive properties were studied. Specifically, yogurts were analyzed for their pH, titratable acidity (TA), firmness, viscosity, water activity (aw), whey syneresis, water holding capacity (WHC), color, probiotic viability, protein and dietary fiber content, and antioxidant activity and total phenolic content (TPC) during 21 days of storage at 4 ºC. Preliminary results suggested that added BRS and GPP in optimum proportions remarkably improved WHC and nutritional, antioxidative and TPC of yogurts. Moreover, added plant-based ingredients did not affect the viability of probiotic culture composed of Streptococcus thermophilus and Lactobacillus bulgaricus during 21 days of storage. However, yogurts supplemented with BRS and GPP had reduced firmness and viscosity as compared to control. Overall, adding plant-based ingredients such as BRS and GPP can be an effective strategy to develop yogurts with enhanced nutritional and functional value.