| China is rich in tea resources, and has the most acreage in the world. Tea seed as a byproduct of tea industry, its oil contains a variety of physiologically active substances and nutrient-rich, which is similar to olive oil. However, few studies were focus on tea seed oil. As a result, there is lack of basic theoretical information and development tools. So the current understanding of tea seed oil is blurring. In this study, we had considered of the tea varieties and extraction methods, defining and re-understanding tea seed oil at fatty acid levels. And oleic and linoleic acids were sync separated using urea package according to their composition characteristics. Then linoleic acid isomerase generated by Lactobacillus was used for transform research on linoleic acid. Eventually tea seed oil containing conjugated linoleic acid was synthesized through combining enzymatic conversion technology and aqueous enzymatic extraction oil process. The main results of this paper are as follows:First, we analyze the fatty acids composition in tea seed oil under different extraction conditions and different tea varieties. The results indicated that, the ratio of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids is about 1.0:2.7:1.3. The relative content of palmitic acid 14.11%~16.99%, oleic acid was 46.33%~55.48%, linoleic acid was 23.17%~29.40%, and the content of three fatty acids is above 90% in tea seed oil. 28 varieties of tea seed oil in this article contains 17 kinds of fatty acids, and 11 kinds of them can be measured in every tea seed oil. Principal component analysis shows that stearic acid, iso-oleic acid, seventeen carbonic acid and palmitic acid are characteristic fatty acids. Different extraction processes makes no significant differences on the relative content of more than 1% fatty acids, such as palmitic acid, oleic acid, iso-oleic acid and linoleic acid, however,it mainly impacts on other trace fatty acids, thus affects the oil quality. The study provides a theoretical basis to identify adulteration of tea seed oil, to obtain high-quality tea oil extraction process, as well as to determine tea varieties.Then, tea seed oil is rich in oleic and linoleic acids. In this study we researched separation and purification of oleic and linoleic acid from tea seed oil with the urea adduction method, and analyzed urea and fatty acid ratio(w/w), ethanol and urea ratio(v/w), inclusion temperature and inclusion time that affect the purity and yield of oleic and linoleic acids. Based on the single factor experiment, tea seed oil oleic and linoleic sync separation process was optimized with central composite experiment. Four response values, the purity and yield of oleic and linoleic acid were weighed by multi-objective analysis. The results showed that: when the ratio of urea to fatty acid ratio(w/w) was 4.1:1, the ratio of 95% ethanol to urea(v/w) was 3.7:1, the crystallization temperature was-3 and the crystallization time was 7.7 h, the ℃ purity of oleic acid was 72.5% and its yield was 84.1%, while the purity of linoleic acid was 91.0% and its yield was 56.4%. This study establishes a safe and efficient sync separation process of oleic acid and linoleic acid, and provides a reference for further development of tea seed oil fatty acids.Taken the linoleic acid as a substrate and by inducing enzyme production of lactobacillus, lantarum linoleate isomerase kept a high acyivity at a fermentation time of 19 h, the concentration of linoleic acid was 3.5 mg/mL, and initial density of 3%. The optimal temperature and pH are 35 ℃and 6.5, respectively. At the optimal conditions of lantarum linoleate isomerase of 2 mL, and substrate(linoleic acid) of 1.5 mg/mL, the conjugated linoleic acid of 191.2 μg/mL was converted.Finally, on the basis of aqueous enzymatic extraction of oil, using pectinase and linoleate isomerase as compounding zymin, the linoleic acid at the extraction process of tea seed oil was modified and the contains conjugated linoleic acid was prepared. The single-factor test was employed to explore pectinase, linoleate isomerase and temperature, and the response surface analysis was used to optimize the conjugated linoleic acid. It is found that the optimal process were pectinase of 6.86 mL, linoleate isomerase of 5.58 mL, reaction temperature of 43 ℃, and the obtained concentration, content, and oil rate of CLA were 43.50 μg/mL, 0.27% and 26.2%, respectively. |
