Study On The Extraction And Oxidative Stability Of Cyperus Esculentus Oil

In this study,Cyperus Esculentus L as the raw material was extracted oil by microwave-assisted extraction and supercritical CO₂ extraction.Response surface analysis was used to optimize the extraction process parameters.The physicochemical properties and fatty acid composition of the oil obtained by different extraction methods were analyzed and compared.At the same time,the removal ability of superoxide anion radical?O₂^-?,DPPH radical and hydroxyl radical of Cyperus Esculentus oil obtained by microwave-assisted extraction,modified soxhlet extraction and supercritical CO₂extraction were tested.Finally,the oxidation stability of Cyperus Esculentus oil obtained by the above methods was studied by oven oxidation.The specific research results were as follows:In the microwave-assisted extraction of Cyperus Esculentus oil,on the basis of single factor experiment,response surface method was used to optimize the extraction conditions.The optimum parameters were obtained as follows:microwave power 609W,liquid/material ratio 10:1?mL/g?,microwave time 15 min,under which the yield of Cyperus Esculentus oil was 24.15%.The structure and composition of Cyperus Esculentus oil were characterized by spectrum.The ultraviolet spectrum showed that there were conjugated dienoic acid,conjugated triaenoic acid and carotenoid in Cyperus Esculentus oil.The infrared spectrum showed the information of functional groups in Cyperus Esculentus oil.The NMR hydrogen spectrum showed the existence of unsaturated fatty acid and sterol in oil.In the experiment of supercritical CO₂ extraction of Cyperus Esculentus oil,based on the single factor experiment,response surface optimization method was applied to optimize the extraction process.The results showed that:the pressure of extraction kettle was 30 MPa,the temperature of extraction kettle was 47?,the extraction time was 188 min,and the yield of Cyperus Esculentus oil could reach 24.90%.Analysis and comparison of physicochemical indexes of Cyperus Esculentus oil obtained by supercritical CO₂ extraction method,modified soxhlet extraction method,and microwave-assisted extraction method,the results showed that the acid value and peroxide value of oil obtained by modified soxhlet extraction were the maximum,while those obtained by supercritical CO₂ extraction were the minimum,iodine value was the maximum and the quality of oil was better.The order of unsaturated fatty acid content of Cyperus Esculentus oil obtained by three methods was as follows:supercritical CO₂extraction?78.171%?>microwave-assisted extraction?77.701%?>modified soxhlet extraction?75.868%?.In the detection of scavenging ability of superoxide anion radical,DPPH radical and hydroxyl radical of Cyperus Esculentus oil extracted by modified soxhlet extraction,microwave-assisted extraction and supercritical CO₂ extraction,the removal ability of Cyperus Esculentus oil obtained by supercritical CO₂ extraction method was the strongest.The scavenging ability was enhanced with the increase of sample concentration.The scavenging ability of the Cyperus Esculentus oil obtained by microwave-assisted extraction on hydroxyl radical and DPPH free radical was higher than that of oil obtained by soxhlet extraction.In the scavenging ability of superoxide anion,the scavenging ability of oil obtained by modified soxhlet extraction and microwave-assisted extraction was similar.In the oxidation stability test of Cyperus Esculentus oil obtained by modified soxhlet extraction,microwave-assisted extraction and supercritical CO₂ extraction,the oxidation stability of Cyperus Esculentus oil obtained by different methods was as follows:modified soxhlet extraction>microwave-assisted extraction>supercritical CO₂ extraction.The Cyperus Esculentus oil structure before and after 14 days of accelerated oxidation was characterized by infrared spectroscopy,and the oxidation stability of Cyperus Esculentus oil obtained by different methods was further verified.