Composition And Antioxidant Activity Of The Citrus Maxima Peel Essential Oils Obtained By Three Different Extraction Methods

The essential oil extracted from grapefruit skin by different methods was discussed inthis article.As for the problems (such as low yield rate, high cost and impurity) present in theextraction, the essential oil extracted from grapefruit skin by different methods was studied inthis article. And a technical route was obtained to meets large-scale production. The maincontents and results of this thesis were as follows.The extraction conditions (different solvents, extraction time and solid/liquid ratio) oforganic solvent extraction method were discussed based on the single factor experimentcombined with orthogonal design. With many factors including price, yield rate and quality ofaroma into consideration, petroleum ether was the best solvent to extract essential oil fromgrapefruit skin. The results showed that the yield rate could reach up to1.59%by theoptimum extracting conditions: temperature,40℃; time,90min; degree of fragmentation,30; solid/liquid ratio,1:20.The extraction conditions (solid/liquid ratio, concentration of limewater and soakingtime) of hydrothermal method were discussed. The results indicated the optimum extractingcondition of hydrothermal method: soaking time,4hour; concentration of limewater,1%;solid/liquid ratio,5:1.The essential oil was extracted from grapefruit skin at the optimum extracting conditionaccording the literature by using supercritical carbon dioxide extraction.Three kinds ofessential oil were identified through physicochemical indicators, and lastly their quality werecomprehensively evaluated by adopting fuzzy assessment and grey relation method.Composition of the essential oil was analyzed through GC-MS. The results showed thatthere were21,45and53kinds of compounds in the extraction by using hydrothermal method,organic solvent extraction method and supercritical carbon dioxide extraction method,respectively. And the mutual compounds for these methods were alpha.-Pinene;beta.-Pinene;Caryophyllene;D-Limonene;2,6-Octadien-1-ol,3,7-dimethyl-,acetate,(Z)-;beta.-MyrcenePreliminary study was done to evaluate the vitro antioxidant activity and scavengingability to DPPH·with phosphorus molybdenum complexing method and DPPH·method. Theresult showed that the sequence of total anti-oxidative capability was BHT> essential oil with organic solvent extraction method> essential oil with supercritical carbon dioxide extractionmethod> essential oil with hydrothermal method; the sequence of free radical scavenging ratewas BHT> essential oil with hydrothermal method> essential oil with organic solventextraction method> essential oil with supercritical carbon dioxide extraction method; thesequence of free radical inhibition rate was essential oil with organic solvent extractionmethod> BHT> essential oil with supercritical carbon dioxide extraction method> essentialoil with hydrothermal method.A production line with annual output of10,000tons’ essential oil from grapefruit skinwas designed, and its related input cost of material, water, electricity and equipment and yieldestimation were calculated.