Study On Selelenium-Enriched Passion Fruit Seed Oil And Its Extraction Technology

Passion fruit seed is one of the by-products of passion fruit juice industry,passion fruit seed contains 18.5-28.3%oil,which is rich in unsaturated fatty acids and has high functional value.Moreover,Se-rich passion fruit seed oil is rich in selenium.Increasing the intake of selenium can maintain health and prevent the occurrence of some diseases.Therefore,the research and development of Se-rich passion fruit seed oil has great scientific value and economic benefits.In this paper,the chemical constituents and antioxidant properties of Se-rich passion fruit seed oil were studied,and the Se-rich passion fruit seed oil was extracted by ethanol water method and supercritical CO₂extraction method.The BIC model was used to simulate the supercritical CO₂dynamic extraction process of passion fruit seed oil.The main contents are summarized as follows:（1）Analysis of oil composition and antioxidant properties of Se-rich passion fruit seedsIn this chapter,the oil composition and oil quality of Se-rich passion fruit seed were analyzed.The results showed that the Se-rich passion fruit seed oil was rich in Selenium element,0.0667±0.0008 mg/kg.The main components were linoleic acid,palmitic acid,oleic acid and stearic acid,and the total amount reached more than 98%.The content of saturated fatty acids was 21.29%,unsaturated fatty acids was 78.71%,and linoleic acid was 68.15%.There are 9kinds of fatty acids（5 kinds of saturated fatty acids and 4 kinds of unsaturated fatty acids）in the oil of common passion fruit seed,among which linoleic acid has the highest content（67.88%）,palmitic acid 17.73%and oleic acid 10.64%.There was little difference in fatty acid content between the two.The results of physicochemical and antioxidant properties showed that the quality of Se-rich passion fruit seed oil was better than that of common passion fruit seed oil.Therefore,Se-rich passion fruit seed oil has great potential to develop functional oils.（2）Study on extraction technology of Se-rich passion fruit seed oil by ethanol water methodIn this chapter,Selenium-rich passion fruit seed oil was extracted by ethanol water method with Selenium-rich passion fruit seed oil as raw material.The effects of single factors such as temperature,liquid-solid ratio,extraction time and ethanol volume fraction on the extraction rate of Selenium-rich passion fruit seed oil were explored.An extraction model was established by RSM-CCD（Response Surface Methodology-Central Composite Design）,and the optimal extraction conditions were obtained as follows:the volume fraction of ethanol was 43.5%,the liquid-solid ratio was 8:1,the temperature was 53℃,and the extraction time was 1 h 55 min.In order to ensure the reliability of the results obtained by response surface method,the experimental extraction yield of Se-rich passion fruit seed oil was 75.41%under the above optimal extraction conditions.Compared with the theoretical prediction value of 76.12%,the relative error was 0.99%.Ethanol water extraction rate was lower than that of soxhlet extraction,ethanol extraction oil acid value and peroxide value were higher than that of soxhlet extraction method to extract oil,and its DPPH（1,1-diphenyl-2-picryl-hydrazyl）radical scavenging ability（IC50（half maximal inhibitory concentration）=7.39 mg/m L）was lower than that of soxhlet extraction（IC50=4.92 mg/m L）,showed that the oil quality was lower than that of soxhlet extraction method to extract the grease,but the ethanol extraction time is shorter,is the advantage of water for 1 h 55 min,far below the soxhlet extraction method used time（6 to 8 h）.Therefore,the ethanol water method has the prospect of industrial application.（3）Supercritical CO₂extraction technology of Se-rich passion fruit seed oilIn this chapter,Selenium-rich passion fruit seed oil was extracted by supercritical CO₂,and the effects of extraction pressure,extraction temperature,static extraction time,dynamic extraction time and CO₂flow rate on the extraction rate of Selenium-rich passion fruit seed oil were explored.The extraction model was established by RSM-CCD,and the optimal extraction conditions were obtained as follows:The extraction pressure was 34 MPa,the extraction temperature was 50℃,the static extraction time was 109 min,and the dynamic extraction time was 97 min.Under these conditions,the actual extraction yield was 72.33%.Compared with the predicted value of 71.56%,the error was 0.77%.Therefore,the quadratic equation model between the extraction rate of Se-rich passion fruit seed oil and the factors variables during supercritical CO₂extraction had a certain significance and a good degree of fit.Compared with the ethanol-water method,the extraction process of supercritical CO₂extraction was more green and environmentally friendly.The extracted oil of passion fruit seed was rich in unsaturated fatty acids,and the content of linoleic acid reached 68.54%,which was higher than that of the oil extracted by ethanol-water method（linoleic acid content was 65.68%）.The acid value,peroxide value and other physical and chemical properties of the oil extracted by supercritical CO₂method were better than those of the oil extracted by ethanol water method and soxhlet extraction method,and its ability to scavenge DPPH radicals（IC50=4.39 mg/m L）was also higher than that of Se-rich passion fruit seed oil（IC50=4.92 mg/m L）extracted by soxhlet or ethanol water method（IC50=7.39 mg/m L）.Therefore,compared with the ethanol water method or soxhlet extraction method,the extraction of Se-rich passion fruit seed oil by supercritical CO₂extraction technology has a better industrial application prospect.（4）Simulation study on mass transfer process of supercritical CO₂extraction of Se-rich passion fruit seed oilThe BIC model was used to simulate the mass transfer process of Se-rich passion fruit seed oil extracted by supercritical CO₂.The results showed that the average relative error（AARD）between the predicted value and the experimental value is between 3.23-4.55%,and the fitting effect is good.The results showed that the model can effectively simulate the dynamic extraction process.Based on the above research on Se-rich passion fruit seed oil and its extraction technology,it was found that Se-rich passion fruit seed oil is rich in selenium elements and unsaturated fatty acids,which had important development potential.Compared with ethanol water extraction and soxhlet extractor method,the extraction of Se-rich passion fruit seed oil by supercritical dynamic and static CO₂extraction technology can better retain the active components of Se-rich passion fruit seed oil,and the supercritical CO₂extraction process is non-toxic and pollution-free,which has the application prospect of industrial production of Se-rich passion fruit seed oil.