Synergistic blending of cold pressed olive and soybean oils with underutilized seed oils to enhance antioxidant functionality and oxidative stability

The aim of this study was to investigate the physicochemical properties, fatty acid composition, antioxidant activity, and oxidative stability of oil blends formulated with soybean (Glycine max) and olive (Olea europaea) oils as base oils and black seed (Nigella sativa), hempseed (Cannabis sativa), and pumpkin seed (Cucurbita pepo) oils as bioactive ingredients. A total of 30 blends were evaluated in ratios ranging from 60:40 to 80:20. Their oxidation parameters (acid value and peroxide value) and fatty acid profiling, along with antioxidant assays (DPPH, ABTS, and FRAP), were assessed. The olive–black seed blend at 60:40 exhibited the most balanced ω-6/ω-3 ratio (2.02) and the highest antioxidant activity (DPPH: 0.377 mg TE/mL; ABTS: 0.66 mg TE/mL; FRAP: 2.36 mg TE/mL). This blend also featured a balanced fatty acid profile with characterized by a suitable ratio of ω-3 and ω-6 fatty acids. Principal component analysis and hierarchical cluster analysis classified the blends into distinct groups based on oxidative and antioxidant properties. The findings revealed the synergistic interplay between fatty acid composition, antioxidant potential, and oxidative stability, pointing out and highlighting the potential of underutilized seed oils, particularly black seed oil, for the development of functional oil blends with improved nutritional quality and oxidative stability.