Understanding changes in volatile compounds and fatty acids of Jincheng orange peel oil at different growth stages using GC–MS

Jincheng orange is widely grown in Chongqing, China, and is largely consumed because of its characteristic aroma contributed by the presence of diverse volatile compounds. The changes in aroma during the development and maturation of fruit are indicators for ripening and harvest time. However, little information available regarding the influence of growth stage on the volatile compounds in Jincheng orange. In addition, volatiles originate from the fatty acids, and most of which were the pre-cursors of the volatile substances. On this basis, gas chromatography hyphenated to mass spectrometry (GC-MS) was performed to elaborate the changes in volatile constituents and fatty acids as precursors. In our study, proximately 60 volatiles and 8 fatty acids were test at 9 growth and development stages (AF1-AF9). Of those compounds, more than 92.00 % of total volatiles and 87.50% of fatty acids were terpenoid and saturated fatty acids, respectively. As shown in PCA plot, the AF5, AF6 and AF9 stages were confirmed as the completely segregated and appeared differences. In addition, almost most of the volatiles and fatty acids showed the first increase at the very beginning of development stage and then decreased from AF6 development stage, and finally increased at maturity of AF9 stages. Moreover, the highest content of terpenoid, alcohols, aldehydes, ketones and saturated fatty acids in Jincheng orange peel oil were d-limonene, linalool, octanal, cyclohexanone and stearic acid during development stages, respectively. Our results found that the growth stages had the significant effect on the volatile constituents and precursors in Jincheng orange peel oil.