The Separation Process And Property Evaluation Of Oil And Polysaccharide From Tea Seed Cake

As the byproduct of tea seed oil extraction,tea seed cake contains certain amount of residual oil and other nutrient and pharmaceutical substances such as polysaccharides,tea saponin,protein,vitamins and flavonoids etc.In this paper,the supercritical fluid(SCF)extraction of oil from tea seed cake was carried out and the composition,thermal stability and antioxidant properties of 3 different tea seed oils were compared.In addition,three polysaccharides fractions were obtained by hot-water extraction and their chemical composition,preliminary structure and biological activity were investigated.In this study,SCF was applied to extract oil from tea seed cake and the process was optimized using single factor experiment and response surface methodology.Experimental results showed that the optimal conditions are as follows: extraction pressure 30 MPa,extraction temperature 53? andextraction time 144 min,and the yield of tea seed cake oil [TSCO(SCF)] is14.78%.The main ingredient in cake are fat and fiber,which is 18.61% and10.53%,respectively.And abundant polysaccharides,protein and tea saponin are also found.The results obtained by component analysis showed[TSCO(SCF)],cold-pressed tea seed oil [TSO(CP)] and tea seed oil extracted by SCF technique [TSO(SCF)] are all abundant oleic and linoleic acid,which account for approximately 80%.Also,they contain trace amounts of linolenic acid.TSO(SCF)containes the highest levels of squalene,lupeol and total sterols,TSCO(SCF)and TSO(CP)has higher contents of total phenolics and ?-tocopherol,respectively.The TG/DTG curves indicated TSO(CP)and TSO(SCF)are more thermally stable than TSCO(SCF)in oxidizing atmosphere.The antioxidant activity assays demonstrated that TSO(CP)exhibites the strongest free radical(DPPH and ABTS)scavenging ability,followed by TSCO(SCF).TSO(SCF)has the best color and oil quality.Tea seed cake polysaccharide(TSCP)obtained by hot water extraction was further isolated and purified on DEAE-cellulose ion column,and TSCP-1 and TSCP-2 fractions were collected.Over 90% of the protein in purified fractions has been removed.TSCP-1 and TSCP-2 both have higher purity and total sugar content is 84.75% and 88.75%,respectively.The main monosaccharide detected of three polysaccharide fractions is glucose,which has relative content of more than 90%.The results evaluated by biological activity showed TSCP exhibites the best antioxidant activities,while TSCP-1 and TSCP-2 have significant inhibitory effects against E.coli and S.aureus.