Boiling-induced changes on physicochemical,bioactive compounds,color,and texture properties of pumpkin (Cucurbita maxima)

Abstract

The objective of the present study was to evaluate the effect of boiling duration on physicochemical, bioactive compounds, antioxidant activity, color, and texture properties of pumpkin (Cucurbita maxima). The pumpkin was subjected to boiling for 1, 5, 10, and 20 min at 100 ℃. The physicochemical analyses showed that pH, moisture, and water solubility index were increased, whereas ash content was decreased with increasing the boiling time. Prolong boiling exhibited a detrimental effect on bioactive compounds of pumpkin, and it was found that 20 min of boiling caused about 25.91% ± 2.21% loss of total phenolic content, 14.79% ± 1.03% loss of total carotenoids content, and 18.46% ± 1.34% loss of antioxidant activity. A kinetic study was conducted to quantify the losses occurring in bioactive compounds, antioxidant activity, changes in color, and firmness of pumpkin. The study revealed that the logistic model can predict the variation in bioactive compounds and antioxidant activity with higher R². However, first-order kinetic models were found suitable to predict the changes occurring in bioactive compounds, antioxidant activity, color properties (L*, a*, b*, Chroma), and firmness. The total color changes (ΔE) showed a good fit with zero-order kinetic models (R²= 0.98). The t_1/2 and D-value were calculated for all measured parameters of pumpkin. These findings would be useful in designing thermal processes and related calculations of pumpkin.