Drying Characteristics of Camellia oleifera Fruit and Shelling Technologies

Experimental studies on technology of drying and removing pudding from Camellia oleifera fruit were conducted.Effects of conventional hot-air drying，heat pump drying and microwave drying on Camellia oleifera fruit shelling were compared and analyzed.It was found that microwave drying cannot achieve shelling due to uneven drying.Using heat pump drying，rate of Camellia oleifera fruit shelling is low，less than 80%，while using conventional hot air drying at 65 ℃ for 6 hours，the rate of shelling could reach 96.97%.The hot-air thin-layer drying experiment were carried out on Camellia oleifera seeds and the Arrhenius equation was used to calculate water diffusion coefficient and activation energy during drying process of oil-tea Camellia oleifera seeds.Results showed that effective water diffusion coefficient of Camellia oleifera seeds was 1.6814×10-9~3.0467×10-9 m2/s，and average drying activation energy was 21.323 7 kJ/mol.The drying process of Camellia oleifera seeds could be described by Sutherland or Paul Singh model.Verification experiments showed that average error between theoretical and actual data was 4.91%.Therefore，the models can be used to predict change of moisture content in different temperatures during drying process of Camellia oleifera seeds.