Effect of Drying Conditions on Functional Properties of Pumpkin Powder

Abstract

Preserving and processing fresh fruit in different forms are among the strategies to reduce food waste and improve food security. As a high-yield fruit, Pumpkin is known to be packed with functional ingredients that could increase its economic value upon being processed. In this context, the functional properties of pumpkin powder dried at different conditions were investigated in this study. De-seeded fresh pumpkin fruits were oven-dried at 50, 60 and 70°C for 48, 24 and 12 hours, respectively. The drying conditions significantly affected moisture content, water absorption and swelling capacities, and colour properties of pumpkin powder (p<0.05). An inverse relationship was observed between drying temperature and moisture content of pumpkin powder, where the values range from 6.57% to 7.44% on a wet basis. Meanwhile, increasing the drying temperature produced powder with increased water absorption, oil absorption and swelling capacities, and bulk density. Thus, it indicates the potential application as a wheat flour substitute in bakery products. However, the highest foaming capacity (0.86%) was recorded for the sample dried at 50°C for 48 hrs. Colour properties of the pumpkin powder revealed that oven drying decreased the lightness (L*) by almost 7% and increased the yellowness (b*) and redness (a*) values by 6% and 2%, respectively when compared to fresh pumpkins. However, prolonged drying at 50°C showed a slight decrement in yellowness and had the lowest L* value, indicating a browning effect and drying at 70°C for 12 hrs produced pumpkin powder with the desirable swelling, water and oil absorption capacities, which is suitable for application as a functional ingredient in various food matrices.