Optimizing pretreatment and extraction methods for high-quality Cinnamomum camphora seed oil: Impacts on bioactive components and antioxidant capacity

This study for the first time systematically investigates the combined effects of shelled/unshelled pretreatments and three extraction methods (cold pressing, CP; hexane extraction, HE; and aqueous enzymatic extraction, AEE) on physicochemical properties, nutritional components, and antioxidant capacity of Cinnamomum camphora seeds oil (CCSO) quality, addressing gaps in synergistic optimization of bioactive retention in CCSO. Lipid yield varied from 37.85 % to 94.26 %, with CP producing the highest total tocopherol content (shelled oil: 328.30 mg/kg and unshelled oil: 291.80 mg/kg) and total phenolic content (TPC, shelled oil: 33.78 mg/kg and unshelled oil: 48.24 mg/kg), as well as the strongest antioxidant activity by DPPH (shelled oil: 109.58 μmol TE/100 g and unshelled oil: 130.95 μmol TE/100 g) and FRAP (shelled oil: 1258.56 μmol TE/100 g and unshelled oil: 1612.33 μmol TE/100 g) assays. In contrast, HE produced lower levels of β-sitosterol, TPC, and squalene, while AEE yielded higher concentrations of monounsaturated fatty acids and β-sitosterol. Shelling increased tocopherol and β-sitosterol contents, but decreased unsaturated fatty acid, TPC, and antioxidant ability. Hierarchical cluster analysis demonstrated that processing method significantly influenced oil properties. Regression and principal component analyses revealed a positive relationship between antioxidant capacity and TPC as well as C18:2. It was determined that Unshelled-CP represented the optimal strategy for producing high-quality CCSO, with strong antioxidant capacity (DPPH-polar: 23.17; DPPH-nonpolar: 43.17; DPPH-oil: 130.95; FRAP: 1612.33 μmol TE/100 g) and high levels of bioactive compounds, making it suitable for food, nutraceutical, and sustainable applications. • Shelled/unshelled pretreatments across three extraction methods for Cinnamomum camphora seed oil (CCSO) were explored. • The influence of processing methods on the characteristics of CCSO is more obvious than that of pretreatment methods. • Unshelled seeds enhance tocopherol and β-sitosterol concentrations. • Unshelled-CP was identified as the optimal method, due to maximizes bioactive retention and antioxidant activity. • Antioxidant activity correlates with phenolic content and C18:2 fatty acids.