Comparative Evaluation of Different Extraction Methods on Chemical Composition, Antioxidant Activity of Mulberry Seed Oil: Pressing, Conventional Solvent, Supercritical Fluid and Micro‐Aqueous Extraction Methods

ABSTRACT Mulberry seed, a byproduct of mulberry fruit processing, is a high oil content oilseed with abundant unsaturated fatty acid and physiologically active substances. The impact of extraction methods on composition and quality of mulberry seed oil (MSO) is critical for its commercial development, however the effect of extraction on its quality is still unknown. Five extraction methods, including cold pressing (CP), hot pressing (HP), Leaching extraction (LE), supercritical CO 2 (SFE‐CO 2 ), and micro‐aqueous extraction (MAE), were adopted to prepare MSO. The effect of extraction methods on the yield, composition and antioxidant activities of MSO was analyzed in this paper. Principal component analysis (PCA) and Mantel test were used for estimating the effect of different extraction methods on oil quality. Results revealed that the yield of MSO extracted with different methods was in range of 61.52%–90.57%, with the SFE‐CO 2 gained the highest oil yield. The free fatty acids (FFA) content and PV from 3.18%–4.84% to 1.34–4.19 meq/kg, respectively. MSO was rich in linoleic acid (76.39%–77.47%). A total of 25 TAG components were identified in MSO, LLL was most abundant TAGs in MSO (37.86%–39.15%), and different extraction methods showed no significant differences on the fatty acids and TAG content. MSO contained β‐sitosterol (382.11–436.71 mg/100 g), Δ‐avenasterol (51.25–64.32 mg/100 g), campesterol (27.04–32.46 mg/100 g) and total tocopherols (2306.80–2849.26 mg/kg), and the DPPH radical scavenging ability of the polar components and whole oil in MSO were 2445.21–3146.1 mg α‐TE/kg and 1341.17–1438.73 mg α‐TE/kg. Mantel test indicated that the antioxidant capacity of MSO was positively correlated with the γ‐tocopherol, β‐tocopherol, Δ‐avenasterol, and campesterol content. PCA analysis showed that the comprehensive quality of MSO ranked as followed: SFE‐CO 2 > CP> MAE> LE> HP. The study provides new insight for the MSO process, and this study is beneficial to the development of MSO in the edible oil industry.