Extraction and Volatile Components Analysis of Peel Oil from Four Varieties of Gannan Navel Oranges

Four varieties of Gannan navel oranges(Newhall,Bonanza,Washington,Navelina)were used as raw materials,the maturity of the fruits was determined by detecting the soluble sugar,titratable acid,soluble solids content and solid-acid ratio,the essential oils were extracted by steam distillation from peels,and the volatile components were studied by gas chromatography-mass spectrometry(GC-MS). The differences in yield,volatile chemical composition and content were compared. Results showed that the solid-acid ratios of the four varieties of navel oranges were all greater than or equal to 20.0,indicated that the fruits were in a mature state. The yields of essential oil from four varieties of Gannan navel orange peels were as followed:Newhall(1.05%)＞Navelina(0.94%)＞Washington(0.91%)＞Bonanza(0.75%). 21 volatile components were identified from four samples,including 13 olefins,3 alcohols and 5 aldehydes,with predominantly olefinic compounds. Besides,eleven kinds of volatile components were identified in the peel of Newhall navel orange,d-limonene(92.962%),myrcene(2.851%)and ocimene(1.039%)were the main aroma components;13 kinds of volatile components were identified in Bonanza,d-limonene(92.328%),myrcene(2.700%),and 3-methylene-6-(1-methylethyl)cyclohexene(1.020%)were main aroma components;Fourteen kinds of volatile components were identified in Washington,d-limonene(92.322%)and β-pinene(2.653%)were the main aroma components;Eleven kinds of volatile components were identified in Navelina,myrcene(47.036%),2-decene(15.313%),3-methylene-6-(1-methylethyl)cyclohexene(11.593%)were main aroma components. The results of this study provided references for the development and utilization of essential oils from Gannan navel oranges.