| The aqueous enzymatic extraction of pomegranate seed oil was introduced in the present work. The influencing factors (solid/liquid ratio, particle size of material, type of enzyme, enzymatic hydrolysis temperature and time, pH and dosage of enzyme) on the yield ratio of pomegranate seed oil were studied by means of single experiments and quadratic regression rotation experiments, the optimum technical conditions were obtained. The kinetic equation of extraction by Alcalase was established. Moreover, the physical and chemical properties, the fatty acid composition, the scavenging capacity of free radical and antioxidant activity of pomegranate seed oil were analyzed to supply a theoretical basis for utilizing pomegranate seed synthetically.The results of the study are as follows:1,The optimum conditions for extracting pomegranate seed oil by Alcalase were confirmed by the single experiments and quadratic orthogonal rotational composite experiments:dosage of Alcalase 1.2%(mL/g), particle size of material 40 screen mesh, solid/liquid ratio 1:5 g/mL, temperature of enzymatic hydrolysis 49.5℃, time 5h, pH=8.0, centrifugation time 25min. And the regression equation with the yield ratio of pomegranate seed oil (Y), enzymatic hydrolysis time (Xi), solid/liquid ratio(X2), temperature(X3) and dosage of enzyme(X4) was established: Y=18.29167+0.21667X1+1.35833X2+0.22500X3+1.48333X4-1.26250X,2-2.90000X22-3.15000X32-1.07500X42+1.10000X1X2-0.42500X1X3-0.23750X1X4-1.47500X2X3-0.63750X2X4-0.71250X3X4 To validate the optimum condition, the average yield ratio of pomegranate seed oil was 20.77% by five parallel experiments in the optimum conditions. The theoretical value calculated by the regression equation was 21.69% and the error was 0.92%. It indicated that the optimized technical parameters were reliable.2,The physical and chemical properties of pomegranate seed oil are as follows:the content of moisture and volatile is 0.1%, specific gravity (20/4℃) is 0.9023, refractive index is 1.5168, acid value is 0.84mgKOH/g, saponification value is 181.67mgKOH/g iodine value is 150.9gI2/100g and peroxide value is 0.91meq/kg.3,The fatty acids composition of pomegranate seed oil extracted by aqueous enzymatic method were isolated and identified by gas chromatography-mass spectrometry. The test results indicate that the eight main components of fatty acids are:punicic acid 82.314%, linoleic acid 4.881%, oleic acid 4.188%, palm acid 2.231%, stearic acid 1.813%, arachidic acid 2.569% and so on. The content of unsaturated fatty acid reaches more than 95%, and punicic acid is 82%. So pomegranate seed oil has high nutritional value and broad development prospects.4,The scavenging capability of pomegranate seed oil to DPPH and·OH is very significantly. The best scavenging rates of are respectively 83.62% and 90.16%, so the capability of anti-oxidation was obvious.5,By Schaal (62±1)℃experiment, the oxidation of pomegranate seed oil was affected remarkably by temperature, not by ray. So pomegranate seed oil can be stored at a certain temperature. At room temperature, POV of oil stored both in light and dark for three years is also below 2.0meq/kg. Pomegranate seed oil has a very good anti-oxidation stability.6,The results show that 5mL/kg.bw·d pomegranate seed oil could remarkably improve SOD, GSH-Px activities in liver and brain tissues, significantly reduce MDA contents in brain tissues and advance protein content in organism. When the dose of oil exceeded 10mL/kg.bw·d, the liver of mice would be damaged to a certain degree. It indicates that an appropriate dose of pomegranate seed oil (≤5mL/kg.bw·d) can enhance the antioxidant function of the body.7,Under the experiment conditions (solid/liquid ratio 1:5 g/mL, dosage of Alcalase 1.2% (mL/g), temperature of enzymatic hydrolysis 49.5℃, time 5h, pH=8.0), kinetic equation of pomegranate seed hydrolyzed by Alcalase is V= 0.02×e(-0.466x), equation of hydrolyzing degree is X=2.146×1n[1+0.048t].
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