Preparation of rapeseed protein hydrolysates with ACE inhibitory activity by optimization and molecular weight distribution of hydrolysates

Objective: The main purpose of this study was to screen effective proteolytic enzymes for producing hydrolysates from rapes protein, and to optimize hydrolysis conditions using response surface design to prepare hydrolysates with maximum ACE inhibitor activity. Methods: RSM design was successfully applied to the hydrolysis conditions on the basis of single factor experiments which further derived a statistical model for experimental validation. The molecular weight distribution of rapeseed protein hydrolysates with different degree of hydrolysis was also investigated. Results: All the proteolytic enzymes tested produced hydrolysates that possessed ACE inhibitory activity. Aiding RSM design the highest ACE inhibitory activity 56.3% was achieved under optimum hydrolysis conditions at the hydrolysis time, pH, hydrolysis temperature, and enzyme dosage were at 90.11 min, 8.88, 50 degrees C and 3580.36 Ug(-1). The mathematical model demonstrated a good fit with experimental results. Furthermore, the molecular weight distribution of rapeseed protein hydrolysates showed remarkable changes, most notably the <500 Da fractions of the rapeseed protein hydrolysates. Conclusion: Enzymatic hydrolysis and response surface methodology found good techniques in order to achieve hydrolysates with maximum ACE inhibitory activity. The findings of current research suggested that the hydrolysates obtained under optimized conditions could be utilized to formulate nutraceuticals and pharmaceuticals.