Insight into the comparison of the nutritional quality and volatile compounds between hot-pressed camellia seed oils from different geographical origins and varieties

This study investigated five hot-pressed camellia seed oils (HPCSOs) derived from different geographical origins and varieties: Camellia vietnamensis (HN1 from Wuzhishan City and HN3 from Chengmai County, Hainan Province; GZ from Gaozhou City, Guangdong Province) and Camellia oleifera (HN2 from Wuzhishan City, Hainan Province; JX from Ganzhou City, Jiangxi Province). First, their physicochemical properties were compared. The results indicated that JX and GZ exhibited poor oxidative stability, characterized by relatively high acid and peroxide values and low contents of squalene, vitamin E, and sterols. In contrast, the Hainan-sourced HPCSOs demonstrated a better balance between nutritional quality and oxidative stability. Among the three Hainan samples (HN1, HN2, and HN3), HN3 maintained the best oxidative stability (lowest acid and peroxide values) while concurrently possessing the highest nutritional quality (greatest abundance of squalene, α-tocopherol, and sterols). The underlying factors influencing nutritional quality and stability were attributed to differences in fatty acid profiles and bioactive compound synthesis, driven by the combined effects of local ecological conditions and varietal genetics. Furthermore, analysis of volatile organic compounds (VOCs) revealed the unique aroma characteristics of each HPCSO and identified 46 core differential VOCs. Cluster heatmap analysis indicated that the numbers of key volatile biomarkers for JX, GZ, HN1, HN2, and HN3 were 13, 8, 4, 6, and 13, respectively. This study provides a theoretical foundation for optimizing variety–region matching and for the authentication of HPCSOs. To identify hot-pressed camellia seed oils (HPCSOs) from different geographical origins and varieties, this study employed GC, UPLC, HS-GC×GC-QTOF/MS (coupled with PCA and OPLS-DA) to compare and analyze the variations in nutritional quality, physicochemical properties, and volatile organic compounds among the HPCSOs.