Efficacy of green processing techniques on the recovery of phenolic compounds from canola meal

• MT was effective in the removal of sinapine from defatted canola meal • Supercritical CO2 extraction technique generated more TPC than MT and HE • Canola meal extracts from MT showed improved metal ion chelation potential • Residual oil level in defatted canola meal influenced phenolics extraction The current study investigated how supercritical CO 2 (SC-CO 2 ) and micro-emulsion techniques (MT) used as green processing methods for the extraction of oil from canola press cake affected availability of phenolics from canola ( Brassica napus ). Canola press cakes obtained from expeller-pressed canola seeds at 60 ℃ from two different sources were subjected to various SC-CO 2 and MT protocols. The resultant partially defatted meals obtained from SC-CO 2 with various levels of residual oil and from MT had their phenolics extracted using ultrasound-assisted extraction (UAE). The phenolic-rich extracts were analysed and quantified by HPLC-DAD. The antioxidant potential of the extracts was also evaluated using in-vitro antioxidant assays (DPPH radical scavenging, metal ion chelation, and ferric reducing power). Results were compared with extracts from de-oiled canola meal prepared by solvent extraction. The results showed that MT defatted meal resulted in the lowest amount of sinapine (219 ± 5 µg/g DW) (M2) while SC-CO 2 defatted meal showed better total phenolic contents (4.65 ± 0.19 mg GAE/g) compared to MT (M2) (0.30 ± 0.04 mg GAE/g). The results of antioxidant activity indicated that extracts from MT defatted meal exhibited the highest metal chelating capacity (75.5%) while extracts from SC-CO 2 defatted meals generally showed increased potential for scavenging the DPPH free radical and reducing the ferric ion to the stable ferrous ion, both different aspects of lipid peroxidation. These findings provide insights on the use of green technologies that will enhance the utilization of canola meal protein for food applications.