Variation of Camellia oleifera fruit traits and nutritional constituents in seed oil during development and post-harvest

Camellia oleifera Abel. is a unique and important edible oil crop in China. The quality and high yield of C. oleifera are closely related to cultivation, management and back-end processing and storage. However, studies on the growth and development, drying treatment and back-end storage of C. oleifera are not comprehensive enough. Therefore, the phenotypic characteristics of C.oleifera fruits during growth and ripening were studied and the effects of four different drying methods including room temperature drying (SW), hot air drying (RF, 65 °C), vacuum drying (ZG, 50 °C, 0.6 Mpa) and freeze drying (LD) on the oil content of C.oleifera seeds (COS) were discussed. At the same time, the changes of the main components and nutrients of C.oleifera kernel oil (COKO) under room temperature storage (SG) and 4 °C frozen storage (LC) were also investigated. The results of the study showed that C. oleifera cultivar ‘Changlin40’ exhibited an S-shaped curve in fruit growth and development. In addition, the oil content initially increased and then remained stable, and the soluble protein and starch contents increased with increasing fruit maturity, but the soluble sugar content increased rapidly at the early stage of fruit development and gradually decreased at the later stage. The maximum content of squalene in the oil obtained by vacuum drying was 80.578 μg/g. The oil content of COS treated by RF was 55.31%, significantly higher than the other treatments. In addition, it was also found that with increasing duration of SG, the acid and peroxide values of COKO increased significantly and the nutrients such as tocopherol, squalene and sterol decreased significantly, which was exactly the opposite of LC, indicating that LC could reduce the loss of nutrients during storage. This study can provide a theoretical basis for field management, screening of drying methods and subsequent storage of C. oleifera.