Effect of variety and cultivation place on the quality of tea (Camellia sinensis O. Kuntze) seed and tea seed oil in Vietnam
The quality of tea seeds and tea seed oils from four popular tea varieties in Vietnam, namely Trungdu, Shan, PH1, and LDP1, grown in Phu Tho, Tuyen Quang, Thai Nguyen, Yen Bai, Nghe An, Quang Tri, and Lao Cai provinces has been identified. The recovery rate of fresh tea seeds ranged from 52.66-64.69%. Chemical components in tea seeds such as protein, ash, lipid and polyphenol content varied in different varieties, but the results of different cultivation places showed no significant difference. In general, the Shan variety had a high content of lipid in seeds (18.45-20.09%), but the recovery rate of seeds was low (about 52.77%). In contrast, the Trungdu variety had a high seed recovery rate (about 64.6%), and the lipid content in the seed was also good (18-20%). Oil quality was determined by physical and chemical indicators (peroxide value, acid value, iodine value, saponification value); Criteria for evaluation of antioxidant capacity (total polyphenols, DPPH free radical scavenging ability through IC50, total carotenoids) of all 15 samples and fatty acid composition in some samples were evaluated as raw materials for producing tea seed oils. In term of oil quality, the tea varieties did not significantly affect the chemical quality and fatty acid composition of tea seed oils. However, DPPH free radical scavenging ability and carotenoid content were the best in Shan seed oil samples in all cultivation places and Trung Du seed oil samples in Phu Tho. Fatty acid profiles of 3 oil samples (2 samples of Trung du seed oil in Phu Tho and Tuyen Quang provinces; 1 samples of Shan seed oil in Yen Bai province) showed that tea seed oil had a high quality.