Study On Extraction And Properties Of Oil And Polysaccharides From Abalone Viscera

Abalone viscera contain biologically active substances,such as protein,fat,polysaccharides,and has great value and wide development prospect.At home and abroad,currently,study on extraction of fat and polysaccharide from abalone viscera is very rare,which leads to the underutilization of the potentially valuable resources.In this paper,supercritical CO₂ extraction technology was used to extract oil from abalone viscera,and the kinds of fatty acids of the extracted oil were analyzed.Then polysaccharides were extracted from the defatted abalone viscera.The technique of extraction,separation and purification,and the basic composition,structure,and the in vitro antioxidant activity of polysaccharides were studied.Current works aimed at doing preliminary exploration for the comprehensive development and utilization of the abalone viscera.The main research contents and results are as follows:1.Extraction of the abalone visceral oil by supercritical CO₂ and analysis of the fatty acid.Supercritical CO₂ was used to extract the oil from abalone visceral.The results showed that the optimum extraction pressure,temperature and time were 31.2 MPa,42.3oC and 9.4 min,respectively.The extraction rate was 75.23%under the optimized conditions.Totally 39 fatty acids with different carbon chain length and number of double bonds were detected which include 9 kinds of saturated fatty acids,8 kinds of monounsaturated fatty acids,and 22 kinds of polyunsaturated fatty acids.2.Study on the extraction technology of polysaccharides from defatted abalone viscera.Trypsin and neutral protease,with a ratio of 1:1,were used to extract ploysaccharides from defatted abalone viscera.The results,which were analyzed by response surface method,showed that the optimum extraction parameters are as follows.The enzymatic hydrolysis time is 3.8 h,enzymolysis temperature is 52.3oC,enzyme pH is 7.1,the ratio of material to liquid is 1:27.2,and the amount of enzyme is 0.79%.Under this condition,the polysaccharides extraction rate was 12.65%.3.Study on separation and purification of crude polysaccharides from defatted abalone viscera.The Sevage method,trichloroacetic acid method,enzyme method,resin method,and enzyme combined with resin method were compared based on their effects of removing proteins.The results showed that the method of enzyme combined with resin was the best choice and the protein removal rate and polysaccharide loss rate reached 77.22%and 6.34%,respectively.Two purified fractions?AVP1 and AVP2?were collected by Sephadex-75 chromatography.Purity identification was carried out by ultraviolet scanning and high performance gel permeation chromatography method.The results showed that the two polysaccharides are all single component.4.A preliminary study of physicochemical properties and structural properties of the polysaccharides.The basic ingredients for AVP1 and AVP2 were as follows.The polysaccharide content was71.68%and 58.26%,the protein content was 0.63%and 0.41%,the uronic acid content was26.55%and 26.41%,respectively.The results showed that the relative molecular mass of AVP1and AVP2 were 223.87 kDa and 19.95 kDa,respectively.The results of IR showed that AVP1and AVP2 all have the absorption peak of polysaccharides.The results of the monosaccharide composition showed that both AVP1 and AVP2 contain rhamnose,galactose,glucose,xylose,and glucuronic acid with a molar ratio of 0.181:1.287:0.313:0.232:0.456 and 0.284:3.179:2.196:0.713:1.359,respectively.5.Study on in vitro antioxidant activity of the polysaccharides.The effects of AVP1 and AVP2 on scavenging superoxide anion free radicals,DPPH free radicals and hydroxyl free radicals were studied.The results showed that AVP1 and AVP2 had strong scavenging ability of all three kinds of free radicals.Their ability of eliminating three kinds of free radicals showed dose-effect in certain concentration range,i.e.,their eliminating effects increases with the increased concentration of polysaccharides.