Investigation of the effects of different processing methods on the selected nutritional properties of pumpkin and determining the appropriate process for pumpkin yogurt

The processing methods, especially cooking, can cause quality losses, particularly in the nutritional value of the fresh product. This study investigated the effects of preprocessing methods on the nutritional properties of pumpkin and the physicochemical and sensory properties of pumpkin yogurt. Two different pumpkin varieties (Cucurbita pepo and Cucurbita maxima) were subjected to three different preprocessing methods (freeze‐drying, boiling, and baking). Boiling significantly increased antioxidant activity (p ≤ .05), followed by baking. C. maxima had higher TDF and TPC than C. pepo, but in both pumpkin varieties, TDF did not change with heat treatment (boiling and baking), while TPC decreased. Mineral contents remained the same or decreased with heat treatment, except for Mn and Fe. In particular, the addition of C. maxima significantly affected the color parameters (L*, a*, b*) of yogurt and improved WHC (from 68.9% to 91.6%) and hardness (from 58.0 to 193.5 g; p ≤ .05). The sensory evaluation concluded that heat‐treated (boiled and baked) samples were preferred more than freeze‐dried raw ones. In conclusion, the results revealed that adding boiled and baked pumpkins, especially the preference for C. maxima instead of C. pepo, improved the quality parameters of yogurt.