Application Of Microwave On The Extraction Of Tea Seed Oil And Refining Of Tea Seed Oil

Tea seed is a by-product of the tea plantation, which is rich in resources. Unsaturated fatty acid content of tea seed oil reaches80%, it also contains VE, squalene, phytosterols and other active ingredients. The Ministry of Health announced in December2009(No.18of2009) approved tea seed oil for the new resources of food.The extraction of tea seed oil mainly are pressing and solvent, this thesis mainly researched the application of microwave on the extraction of tea seed oil by pressing and solvent, the purposes are that exploring the effect of microwave on the yield and qualities of tea seed oil, and improved refining processes of tea seed oil. Thesis research results are as follows:1、 The tea seed oil extraction rate of microwave-assisted extraction is higher than the rate of microwave-pretreatment extraction; They are both higher than the rate of no microwave treatment. The optimum conditions of microwave-assisted extraction tea seed oil are high fire microwave time2min, extraction1h, extraction twice, and moisture content of7.5to10%, under these conditions, the extraction rate reached98.81to98.93%. With the the microwave time extension, solid lipid content of tea seed oil extracted by microwave assisted is lowering, but are lower than without microwave processing. Solid lipid content is high, the melting point of the solid lipid is low, and between the correlation coefficient was0.948. Ethanol-water ratio have no significant impact (P>0.05) on the Y (yellow) value of tea seed oil. With ethanol-water ratio increases, the extraction rate of the tea seed oil, R (red) value, and the solid lipid content are reduce. When ethanol-water ratio is greater than or equal to3:1, the solid fat content is0.2、Response surface methodology was employed to optimize the technology of tea seed oil which is squeezed with microwave, and a mathematical model was created to describe the effects of the moisture content, microwave output power density, microwave time, and particle size on oil yield. Moisture content26.8%, microwave output power density15.81W/g, microwave time78s, and particle size70mesh. Under these conditions, the experimental yield was22.02%, and the extraction rate of oil was78.3%. The physicochemical properties of tea seed oil is no significant difference with low-temperature squeezing tea seed oil, and its aroma is better than the aroma of squeezing tea seed oil at low-temperature. 3、 Under optimal conditions, the yield of microwave pretreatment press tea seed oil was21.81%, which is higher than baking (baking temperature:60～120℃) after pressing oil, and the absorbance at420nm was no significant difference with60°C,80°C baking pressing tea seed oil, but lower than absorbance value of120℃baking pressing tea seed oil; AV, POV, CGV squeeze tea seed oil below after baking. Analyzed by principal component, color, POV and CGV have correlation, AV and smell and taste and CGA positive correlation, negative correlation with the color and POV, when the moisture content is too low or the microwave output the power density is too large or the irradiation time is too long, which have impact to qualities of tea seed oil. Regression model between the the microwave pretreatment conditions and physical and chemical properties of tea seed oil by pressing are: Y,(color)=(648-8.839X1-17.589X3+0.23X22+0.23X32-0.631X2X3)×10-3Y2(AV)=5.505-0.08X3+0.001X12-0.017X12+0.007X2X3Y3(POV)=(13.696-0.187X3+0.007X22+0.002X32-0.001X1X3)×10-2Y4(CGV)=5.868+0.029X12+0.016X22+0.003X32-0.013X,X3Where, X1is the moisture content; X2microwave output power density; X3microwave time.4、 With the extension of the irradiation time, the oxidative stability of tea seed oil by pressing enhanced. The oxidation stability of tea seed oil by pressing with microwave pretreatment is higher than60℃roast pressing tea seed oil and is quite100℃roast pressing tea seed oil. With the microwave time extension, tea seed oil unsaponifiable matter content increased, the total phytosterol content also increased. Microwave120s, the unsaponifiable matter content of tea seed oil by pressing was no significant difference (P>0.05) with at100℃,120℃bake pressing tea seed oil. And the mainly sterol in unsaponifiable matter are sitosterol, avenasterol, lanosterol, also contain active ingredients such as squalene, the fragrance ingredients of β-methyl ionone also contain.5、 Tea seed oil low temperature alkali refining can achieve the effect of high temperature alkali refining and soap is not easy to go up and broken at low temperature alkali refining, so resulting is not easy emulsification. Each of the refining process, the unsaponifiable matter content has decreased, the degree of reduction is followed by deacidification> decolorization> deodorized. Low temperature alkali refining and high temperature alkali refining have no effect on the unsaponifiable matter content. Activated carbon, clay, diatomaceous earth, silica can strongly absorb yellow and unsaponifiable matter. The adsorption capacity of four deodorant order activated carbon> clay>diatomite> silica. Oleic acid content of the liquid oil by4℃winterization is higher than refined oil, oleic and linoleic acids in the solid fat content decreased, the palmate acid content increased, changes in the content of other fatty acids, is not detected in the solid fat palmate oleic acid and21carbon acid.