Impact of ultrasound on pumpkin seed protein concentrate hydrolysis: Effects on Alcalase, protein, and assisted reaction

Ultrasound (40 kHz, 23.8 W/L) was applied (pH 7.5, 25 - 60 degrees C, up to 300 min) to Alcalase (protease) and pumpkin seed protein concentrate (substrate) as a pre-process or during proteolysis aiming to improve the hydrolysis rate, the final concentration of hydrolysates, and its solubility and in vitro antioxidant activity. The pre-process applied in enzyme and substrate increased the relative activity of the enzyme by 10.3 and 50.1%, respectively (p<0.05). Moreover, pre-sonication of protein and ultrasound-assisted hydrolysis provided up to 280% increase in the proteolysis rate and resulted in up to 24% higher concentration of soluble peptides, compared to conventional hydrolysis (p<0.05). Consequently, the hydrolysates obtained with ultrasound intervention had greater solubility (<= 148.1%, p<0.05) and higher radical scavenging capacity than those produced through conventional hydrolysis. From the overall evaluation of the results, and considering the operational costs and equipment wear, we concluded that pre-sonication of pumpkin protein is the best strategy to enhance the generation of hydrolysates with better multifunctional properties.