Characterization and Comparison of Commercial Pumpkin (Cucurbita moschata) Seed Oils from Various Brands in China

Pumpkin seed oil (PSO) is becoming increasingly valued for its nutritional profile and minor bioactive constituents. Here, we surveyed PSOs marketed in China and hypothesized that differences in antioxidant constituents help explain variability in oxidative stability across brands. Sixteen commercial products labeled as pumpkin (Cucurbita moschata Duchesne) seed oils, including two imported brands (France), were analyzed for physicochemical quality indices, fatty acid composition, oxidative stability, and bioactive components (tocopherols, total sterols, and total phenolics expressed as gallic acid equivalents). Acid value, peroxide value, and iodine value ranged from 0.22 to 4.30 mg KOH/g, from 4.63 to 11.57 mEq O₂/kg, and from 106.64 to 132.77 g I₂/100 g, respectively, and all samples complied with applicable regulatory limits. Oleic and linoleic acids predominated (21.79-35.50% and 44.99-57.03% of total fatty acids, respectively), consistent with a highly unsaturated oil matrix. Total phenolics varied widely, reaching 2247.78 mg GAE/kg, while total tocopherols and total sterols ranged from 268.26 to 528.26 mg/kg and 733.64 to 1095.99 mg/kg, respectively. Oxidation induction times ranged from approximately 4 to over 10 h, and radical-scavenging activity differed markedly among samples. Correlation analysis and principal component analysis consistently identified δ-tocopherol, total sterols, and total phenolics as the variables most strongly associated with oxidative stability and antioxidant performance. Overall, these results provide a market-level snapshot of compositional variability in PSOs sold in China and highlight antioxidant-related markers that may support quality differentiation and process optimization.