Study On Drying, Storage And Squeezing Technology Of Camellia Oleifera

Camellia oleifera, as Chinese endemic woody plants oilseed, was mainly used in producing Camellia oleifera oil. In recent years, the Camellia oleifera industry is heating up year by year under the national policy support, and the seed output improved gradually. So, the requirements for technical and processing capacity were higher for Camellia oleifera processing plants. However, the existing pretreatment and squeezing technology was only suitable for small lot processing. The main contents of this paper were listed as follows:Moisture sorption isotherms of shelled and unshelled Camellia oleifera were determined by using a gravimetric static method at 20, 30 and 40°C with water activity ranging from 0.111 to 0.976. Estimated parameters and fitting ability of seven models were evaluated, and the Peleg model provided the best description of the experimental sorption behaviour. The experimental data and the models were also used to obtain thermodynamic functions. The differential enthalpy decreased rapidly as the moisture content increased, when the moisture content exceeded 7% (dry basis) the value of differential enthalpy approached to zero. The differential entropy showed similar trends. Spreading pressure increased with increasing water activity and decreased with increasing temperature at a given water activity. Net integral enthalpy increased slightly with moisture content to a maximum value, and thereafter decreased with increasing moisture content. However, net integral entropy decreased gradually with increasing moisture content to a minimum value, and then increased slightly with further increases in moisture content.The storage stability of Camellia oleifera was studied by being stored at different water activity conditions, and then determined the Camellia oleifera oil quality to evaluate the effect. The results showed that: the Camellia oleifera didn't appear mildew pest phenomenon after 7 months stored under a relative humidity lower than 75.5%, and the contained oil showed a low degree of oxidation, but declined in antioxidant capacity; when the relative humidity was over than 80%, the Camellia oleifera appear mildew phenomenon, and the oil quality became bad, so the storage period should not exceed 5 months under this condition.Four drying methods were selected and compared, and then the effect on the storage stability of the contained Camellia oleifera oil was evaluated. We observed the microstructure of Camellia oleifera processed by four drying methods. In order to establish the hot-air dying model, we chose four mathematic models to fitting the experimental data of hot-air drying at 50, 70, 90°C. The results showed that: it's best to adopt the hot-air drying method to process the Camellia olrifera, and the time needed to reach the goal moisture content 9% was 20, 7.5, 5 h at 50, 70, 90°C, respectively. It's proved that the Camellia oleifera processed by hot-air drying had good storage stability. The observing results of SEM showed that microwave drying and 90°C hot-air drying method generated the vastest moisture transfer channel. The result of non-lineal regression analysis proved that the Page model provided the best fitting results and description of the hot-air drying procedure of Camellia oleifera.