Subcritical water extraction of hydrolyzed proteins from canola meal: Optimization of recovery and physicochemical properties

The objective of this study was to valorize hot-pressed, desolventized toasted canola meal by tailoring subcritical water extraction (SCW) conditions to enhance protein recovery while optimizing their physicochemical properties. A 3×3 face-centered central composite design using response surface methodology was applied to understand the interaction between extraction temperature (200-250°C), time (20-30 min), and feed concentration (5-20%) at 4.03 MPa pressure and their effects on protein recovery, degree of hydrolysis (DH), interfacial tension (IFT), and total phenolic content (TPC). The extracts displayed a maximum protein recovery of 68.9 wt% with a maximum DH of 14.1%. The extracted protein significantly reduced the IFT to a minimum of 4.0 mN/m. The extracts showed a high value of TPC (24.6 mg/g) and excellent antioxidative properties. Overall, it demonstrates the potential of SCW to transform low-value canola meals into high-value protein hydrolysates with enhanced surface activity and antioxidative properties for food and industrial applications. • Subcritical water extraction was performed on hot-pressed canola meal • Hydrolysates with a maximum 68.9% protein yield was obtained at 225°C/25 min/5 wt% • The maximum degree of hydrolysis (14.1%) was obtained at 250°C/30 min/5 wt% • SDS-PAGE confirmed the hydrolysis of most of the canola peptides below 10 kDa • Subcritical extracts showed excellent antioxidant activity due to high phenolic load