Abstract:

The drying procedure is extremely important to the storage and processing of Camellia oleifera seed and to the quality of Camellia oil. In order to optimize the drying technology and reduce energy consumption, the effects of hot-air drying, microwave drying and natural drying on the stability of oil were analyzed, and the law of the effects of temperature and bulk density on the drying characteristics of Camellia oleifera seed is investigated. Then, a mathematical model describing the drying procedure is established by integrating the three models. The results show that （1） hot-air drying is more suitable for Camellia oleifera seed; （2） the drying rate increases with the increase of temperature and with the decrease of bulk density; （3） it takes 20, 15 and 13 h respectively to attain a relative safe moisture content for storage at the drying temperatures of 40, 55 and 70 ℃ ; and （4） the drying time cost reaches 15, 20, 22 and 25 h when the bulk densities are 322, 354,430 and 442 kg/m³ , respectively. Moreover, it is demonstrated by the linear regression of the three common drying models that the Page model accurately describes the hot-air drying process of Camellia oleifera seed, with an average relative error of 5.72% between theoretical values and experimental ones. It is, thus, concluded that, for the drying of Camellia oleifera seed, the Page model can predict the drying rate and moisture content more accurately.

Key words: Camellia oleifera seed, drying characteristic, mathematical model