Study On Main Chemical Components And Extraction Technique Of Essential Oil From Citrus Flower

Citrus flowers exist with abundant resources, however, the main chemical composition, biological activity and new essential oils extraction technologies have rarely reported. This study determined the chemical composition of citrus flowers, and for the problem of low yield rate of essential oils presents in traditional extraction, conducted a series of researches on the extraction process and product quality of essential oils, provided a theoretical basis for its application in more areas. Following results are obtained:The main components and contents of citrus flowers were determined and analyzed, results showed as follows:moisture content is856.2mg/g; dry basis content:protein49.5mg/g, amino acid7.7mg/g, total organic acid31.4mg/g, polysaccharide10.6mg/g, reducing sugar,9.5mg/g, total sugar153.1mg/g, essential oil of11.5mg/g, flavone7.7mg/g, total alkaloid26.7mg/g.Response surface methodology experiments was applied to optimize the microwave-assisted extraction technology of essential oil from citrus flower, the optimal microwave-assisted extraction condition was determined as follows:the extraction agent was n-hexane, microwave power420W, liquid to solid ratio6.4:1(mL/g), microwave treating time185s.Under this optimum condition, the extraction yield of essential oil was1.040%, the yield of essential oil extraction was90.43%.Response surface methodology experiments was applied to optimize the supercritical CO2extraction technology of essential oil from citrus flower, the optimal supercritical CO2extraction condition was determined as follows:the freeze drying time was8h, particle size was20,the temperature was46℃, the time was3.2hours and the pressure was320bar. Under this optimum condition, the yield of essential oil was up to1.051%, the yield of essential oil extraction was91.39%.Physics and chemistry indexes of citrus flower essential oil extracted by microwave-assisted extraction and supercritical CO2extraction technology were determined in accordance with reference standard. Compositions were identified by gas chromatography-mass spectrometry (GC-MS) and the relative contents were calculated by area normalization method. Preliminary study was done to evaluate the vitro antioxidant activity and scavenging ability to DPPH with phosphorus molybdenum complexion method. The result showed that the sequence of total anti-oxidative capability and free radical scavenging ability both were BHT> essential oil with microwave-assisted extraction method>essential oil with supercritical carbon dioxide extraction method.