Effects of Varieties, Cultivation Methods, and Origins of Citrus sinensis ‘hongjiang’ on Volatile Organic Compounds: HS-SPME-GC/MS Analysis Coupled with OPLS-DA

Volatile organic compounds (VOCs) in Citrus sinensis ‘hongjiang’ oranges significantly vary depending on the fruit variety, cultivation mode, and cultivation location. The effect of these three factors on VOCs was experimentally determined in this study. In total, 102 VOCs were separated via headspace solid-phase microextraction and identified via gas chromatography-mass spectrometry, and the differential components were analyzed by partial least-squares-discriminant analysis (OPLS-DA). The VOCs of ‘hongjiang’ mainly comprised alkenes, alcohols, aldehydes, and ketones. They were well clustered in OPLS-DA and principal component analysis (PCA), and the seven groups were distinctly differentiated. The results of the S-plot, variable importance in projection (VIP), and heatmap analyses showed that these factors had a significant impact on VOCs in ‘hongjiang’. The characteristic VOCs between the two pairs were significant, while the net room cultivation mode had the most substantial effect on VOCs.