Study on the Extraction of Hawthorn Seed Oil by Supercritical Carbon Dioxide and Analysis of Chemical Compounds in Hawthorn Seed Oil
|School||Northwest University of Science and Technology|
|Keywords||hawthorn seed hawthorn seed oil supercritical CO2 extraction physical and chemical index Gas chromatography-mass spectrometry Chemical constituents|
Hawthorn seeds is about 30 % weight of the total dry hawthorn fruit and is rich on seed oil and functional activity compounds, such as Vitamin E,linoleic acid, linolenic acid, flavanone, squalene and so on. The hawthorn seed oil is used in the fields of food, cosmetic and medicine. Therefore, it is of important social significance and commercial values to investigate extraction these useful components from the abandoned hawthorn seed. With occurring the upsurge of savageness, nutrition and returning natural all over the world, supercritical fluid extraction technology holds prominent status in the fields of extraction of natural products as kind of high effective and clean separation technology. This thesis mainly explores the feasibility and optimal conditions of extracting seed oil from the abandoned hawthorn seed with supercritical carbon dioxide; meanwhile, the content of volatile constituents, mainly fatty acid, polyhydroxylated and some functional activity compounds were studied.The process of extracting oil from hawthorn seed by supercritical CO2 was first studied. The orthogonal experiment was adopted to study the extraction technological conditions. And the influences of extraction temperature, pressure and time on the extraction yield of ten seed oil were investigated. The experimental results showed that the optimal conditions of supercritical CO2 fluid extraction were extracting 3 hours at 40℃, 30 MPa; the extracting rate was higher when the hawthorn seed has a little water, it was optimal that the content of water was 7%.The quality test were also carried out and the test results demonstrate the hawthorn seed oil extracted with supercritical carbon dioxide has satisfied with the routine quality index of physical and chemical characters for the refined edible vegetable oil according to the national sanitation standard. The results of determination are: the acid value was 1.08 (mgKOH/g oil), iodine value was 122.81, saponification value was 201.04(mg KOH/g oil), non- saponification was 4.2%, the content of protein was 2.31%, relative density was 0.9271(20℃), refractive index was 1.4771(20℃). The volatile and semi-volatile constituents in the seed oil were isolated and identified by gas chromatography-mass spectrometry method. 36 compositions were separated from hawthorn seed oil , 31 compounds were identified and they represent 91.49% of the total peak areas. The relative contents of constitutes were determined by area normalizing method. The main constituents were: Linoleic acid ethyl ester(27.32%), VitaminE (10.18%), Squalene (8.02%),β-sitosterol (5.76%), etc.A method for the analysis of squalene and vitamin E in Hawthorn seed oil by gas chromatography-mass spectrometry (GC-MS) method was developed. The contents of squalene and vitamin E in hawthorn seed oil were simultaneously determined by internal standard curve method using n-dotriacontane as internal standard. The results showed that the average added standard recovery of the method developed by this paper was in the range of 96.4-102.2 %, the relative standard deviations (RSD) were less than 3.0 %, the correlation coefficients were more than 0.999 and the detection limits were in the range of 2.0-2.5 mg/L. The contents (mg/g) of squalene and vitamin E in Hawthorn seed oil are 2.92 and 2.31. The contents of total in seed oil and in seed kernel were 4.18mg/g and 11.22mg/g.A method was developed for the analysis of polyhydroxylated compounds in hawthorn seed oil by gas chromatography. The process involved solvent partition, trimethylsiylation and capillary column gas chromatography. The relative contents of constitutes were determined by area normalizing method. The mainly polyhydroxylated compounds were: glycerol (9.74%), glucitol 8.34%), etc. polyhydroxy was identified as Benzoic acid, 3,4-dihydroxyl and one flavonoid was identified as 7H-Furo[3,2-g] chromen-7-one, 2-benzoyl-3, ethyl-5,9-dimethyl. The method provided an effective reference to analyzing polyhydroxylated compounds in edible vegetable oil.The acidic components of hawthorn seeds oil were etherified in 12.5% H2SO4-CH3OH solution. The organic acid methyl esters were extracted by CH2Cl2 and they were analyzed by gas chromatography-mass spectrometry (GC-MS). 17 acidic compone- nts were separated and the chemical structures were identified. The main higher fatty acids were linoleic acid(63.87%), oleic acid(24.17%) and Hexadecanoic acid(1.67%), etc.