Drying kinetics and microstructural characteristics of hot-air dried and roasted pumpkin (Cucurbita pepo L.) seed

作者：Huang Wencheng; Wang Lu^*

来源：International Agricultural Engineering Journal, 2018, 27(3): 333-341.

• Drying kinetic
• Effective moisture diffusivity
• Hot air drying
• Micro-structural characteristics
• Pumpkin seeds
• Roasting
• Roasting experiments
• Seed moisture contents

Hot-air drying and roasting of pumpkin (Cucurbita pepo L.) seeds are the critical processes that affect the qualities of oil and snack. Fresh pumpkin seeds are generally dried by a forced convection dehydrator and a wok. In this paper, hot-air drying experiments were conducted at 50°C, 60°C, and 70°C. Temperatures of 140°C, 150°C, and 160°C were used for roasting experiments. Seed moisture contents were measured each hour during hot-air drying and 5 min during roasting period. The Lewis model and the Page model provided the best goodness of fit for the hot-air drying and the roasting processes, respectively. The effective moisture diffusivity values ranged from 1.79×10-10-4.13×10-10m2/s for hot-air drying and 5.00×10-9-9.34×10-9m2/s for roasting. Roasting led to a higher value of activation energy (52.69 kJ/mol) than hot-air drying (38.37 kJ/mol). Microstructures of pumpkin seed were observed and evaluated using a scanning electron microscope. A higher temperature resulted in a greater extent of disruption in pumpkin seed cell structure. More pores and breaks were developed for the roasted seed.

• 出版日期2018