The Analysis Of Volatile Compounds And Nutrition Composition In Camellia Oil

Tea seed oil(camellia oil) is one of the most common edible oil, not only rich in unsaturated fatty acids, but also natural bioactive compounds including vitamin E, squalene and polyphenols. The prevalence of camellia oil mainly distributes in the south of the Yangtze River in China. Till now, available information about the quality of camellia oil and its organoleptic flavor characteristics is limited. Therefore, the nutrients compounds, toxic substance and flavor compounds in camellia oil were analysed in the present study. The results will provide available scientific data and technical support for the assessment of adulteration in camellia oil and oxidation degree. The main results are as follows:1. The nutrient compositions including vitamin E, squalene, polyphenols, fatty acids and the toxic substances benzopyrene in tested camellia oils were analysied by using high-performance liquid chromatography(HPLC), gas chromatograph(GC) and colorimetric assay. The results showed that the vitamin E content, mainly alpha isomer, ranged from 9.71 mg/100 g to 31.01 mg/100 g among tested camellis oils, and most of the tested oil samples were around 20.00 mg/100 g. Camellia oil in tested samples were mainly rich in unsaturated fatty acid, among which the monounsaturated fatty acids accounted for more than 75%, and the polyunsaturated fatty acids were 5%- 10%. Squalene contents were from 6.17 mg/100 g to 21.63 mg/100 g. Phenolic contents determined by colorimetric assay were between 5.496μg/g to 35.763 μg/g. The benzopyrene contents among all tested samples were less than 10μg/kg, following the requirement of China national standard GB2762-2005. The Vitamin E and ohenolic contents showed positive correlation with the squalene and benzopyrene contents, respectively.2. After comparing the extraction efficiency of solid phase microextraction(SPME) and simultaneous distillation-extraction(SDE), the results showed that SPME was better than that of SDE in extracting the volatile compounds of camellia oil. The optimized analysis conditions are as follows: the extracting temperature is 60 ℃; the extracting time is 50 min; the resolving time is 4 min; helium carrier gas flow rate set as 0.8 m L/min; the resolving temperature set as 250 ℃. The principal component analysis(PCA)results showed that nonanal, 2-pentylfuran, trans-2-nonenal, octanal and hexanal were the major flavor compositions in three selected camellia oils.3. The volatile compounds identified in 34 tested camellia oil included: 15 alcohols, 15 aldehydes, 10 ketones, 10 organic acids, 13 phenolics, 28 carbonhydrate and 30 other compounds. The mainly volatile compounds in camellia oil were hexanal, heptanal, octanal, nonanal, decanal, benzene acetaldehyde, 2-pentylfuran, limonene and(E,E)-2,4-decedienal, the content of which was about 56.62%. The content of nonanal, decanal and octanal produced by the oxidation of oleic acid was about 28%. Meanwhile, hexanal, nonanal and decanal should be contained in camellia oil. The majority of the volatile compounds were aldehydes. The sensory characteristics of these compounds presents green, fruits and fat flavor, which is consistent with the natural senses of camellia oil.4. The contents of vitamin E, squalene and phenolics decreased during the refining process of camellia oil due to the effects of processing conditions including strong alkali, high temperature. Therefore, mild refining process could maintain the majority of the natural bioactive compounds in camellia oil, which is also the development trend of edible oil industry. The concentrations of volatile compounds including hexanal, octanal, nonanal and(E,E)-2,4-decedienal had a trend of increasing first then decreasing and reached the maximum at the processing of water washing and dewatering. Benzene acetaldehyde and limonene reached the highest point in the virgin camellia oil.