| In this paper, four main subjects were studied, including the optimization of microwave pretreatment assisted supercritical CO2 fluid extraction used to extract camellia oil and the quality analysis of camellia oil, the advantages analysis of series of camellia oil production in low temperature, the recycle techonologies and antioxidant research of tea seed polysaccharides isolated from camellia seed aqueous degreasing fluid.By orthogonal experiment design combined with the single experiment results, the optimal microwave pretreatment conditions of camellia seeds were as follows:camellia seed kernel with a 7.8% moisture content were crushed to be particle size of 150μm with microwave processing for 120s. Then the effects of extraction pressure, temperature and time on camellia oil extraction efficiency were evaluated using response surface methodology. The optimal conditions of microwave pretreatment assisted supercritical CO2 extraction for producing camellia oil were as follows:extraction pressure 33 MPa, temperature 45℃ for extracting 2h. Under this optimum condition, the camellia oil extraction efficiency was 92.76% and was far higher than that without microwave processing method. The extracted oil with a satisfying vitamin E content of 182.4 mg/kg can meet the requirement of the pressing first class camellia oil followed by simple deacidification process. This new technology was found that better improving the extraction efficiency, ensuring the raw quality of camellia oil, and shortening the production cycle.Five new type of oil production in low temperature including cold pressing, supercritical CO2 extraction, microwave pretreatment assisted supercritical CO2 extraction, general microwave assisted extraction and weakly acidic aqueous solution extraction were selected to compare with traditional methods like hot pressing and solvent extraction on physicochemical properties, fatty acid compositions, vitamin E content, squalene content and harmful ingredient Benzo(a) pyrene content in extracted camellia oil. The "liquid gold" olive oil was set to be a positive control group. The comprehensive conclusion showed that oil productions in low temperature proved to have series of advantages, such as shorten the process, protect the unsaturated fatty acids, maximize the retention of vitamin E and bioactive ingredients like squalene, prevent Benzo(a) pyrene exceeded, etc.The waste camellia seed aqueous degreasing fluid produced by weakly acidic aqueous solution extraction method was recycled to obtain crude tea seed polysaccharides using vacuum concentration, ethanol precipitation, lavation with ethanol and vacuum freeze drying methods. TCA method was confirmed as a better protein removal process when compared with Sevage method. The optimal conditions were as follows:TCA concentration 18%, ratio of crude polysaccharide to TCA 1:3, standing in 35℃ water bath for 45min. Once assisted with 4℃ refrigerator stalling for 48 h, the protein removal rate and polysaccharide retention were 81.18% and 85.98% respectively. The further optimum powder active carbon decoloring process was obtained by orthogonal experiment design. The optimum decoloring conditions were as follows:activated carbon content is 2.0%, adjusting the pH to 5.5, concussion decoloring 40 min in 60℃ water bath. Under this condition, the polysaccharide decoloration rate and polysaccharide retention rate were as high as 96.86% and 90.17%, respectively.The antioxidant potential of tea seed polysaccharides was preliminary detected by hydroxyl radical scavenging, ferrous ion (Fe2+) chelating, superoxide anion radical scavenging, and reducing power assays, as compared to ascorbic acid (VC) and tertiary butyl hydroquinone (TBHQ). Results showed that the recycled polysaccharides showed strong Fe2+ chelating ability with the potential as a metal chelating agent. On the other hand, the polysaccharides only showed the potential of scavenging free radicals in relatively high concentrations. |
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