Study On New Extraction Processes And Quality Of Camellia Oil

There are many researches on oil extraction, of which the conventional methods include mechanical pressing and organic solvent lixiviation process. In this research, the tea-seed, which is a kind of traditional oilseed from woody plants, was chosen as the raw material to explore a new extracting method and conditions of supercritical CO2extraction, aqueous extraction and aqueous enzymatic extraction were optimized. The quality and fatty acids composition of camellia oil extracted by different methods were studied. Main results are presented as follows:1. Process parameters (extraction temperature, pressure and time) of supercritical CO2extraction was optimized by single factor tests and orthogonal tests. It was found that each factor affecing the yield of camellia oil decreased in the order extraction pressure>extraction temperature>extraction time. The optimal process parameters: extraction pressure30MPa, extraction temperature45℃, and extraction time2.5h. In this condition, over95%of camellia oil was extracted, which indicated that the camellia oil can be completely extracted by supercritical CO2extraction.2. The results showed that, the oil yield of tea-seed treated by microwave was significantly higher than that untreated by microwave, which suggested that microwave process promoted yield of camellia oil by aqueous extraction. The results of single factor tests showed that the effects of microwave time, solid-liquid ratio, extracting temperature and time were greater than that of centrifugal speed and time. According to the orthogonal tests, the yield of camellia oil (62%) was obtained under the optimal parameters as follows:microwave time120s, extract5%NaCl, solid-liquid ratio1:4, bath temperature85℃, bath time2.5h, centrifugal speed4200r/min, and centrifugal time15min.3. According to the investigation of the aqueous enzymatic extraction of camellia oil, it can be found that the yield of oil extracted before and after enzymatic digestion, respectively, was obviously better than that only extracted after, enzymatic digestion. The oil yield of tea-seed treated by microwave was significantly higher than that untreated by microwave, which suggested that microwave process can promote the process of tissue crush of the oilseed. Compared with the tea-seed group untreated with enzyme, all the other groups added with enzymes could promote the yield, of which the complex enzyme had the most significant effect on increasing the oil yield. Through single factor tests and orthogonal tests, The yield of camellia oil was up to83%obtained by the optimal parameters:solid-liquid ratio1:4, bath time30min, bath temperature90℃, microwave time120s, digestion pH6.5, digestion temperature50℃, addition quantity of compound enzyme0.9%(w/w), remixed ration6:5, centrifugal speed4200r/min, and centrifugal time15min.4. For the quality study of camellia oil extracted by different processes including aqueous enzymatic extraction, aqueous extraction, mechanical pressing process, supercritical CO2extraction and organic solvent lixiviation process, it was found that the oil obtained by aqueous enzymatic extraction and aqueous extraction had similar indexes values and better quality, with lightest and clearest color as well as lowest density, acid value and peroxide value. The squalene and VE content in camellia oil varied among the different extracting methods. The camellia oil obtained by the mechanical pressing had the highest content of squalene and the oil extracted by supercritical had the highest content of VE. The contents of squalene and VE in camellia oil extracted by aqueous Enzymatic, aqueous and solvent extraction, respectively, were similar. The oil produced by pressing had lowest content of VE. The content of unsaturated fatty acid of camellia oil extracted by different methods was all up to90%, of which the content of oleic acid and linoleic acid was about75%～85%. The main components of saturated fatty acid were palmitic acid and stearic acid, both of which were about10%. This suggested that the fatty acids composition of camellia oil extracted by all these methods showed no significant differences.