Protease‐assisted process for tryptophan release from pumpkin ( Cucurbita maxima ) seed protein extracts

Abstract

Squash pumpkin (Cucurbita maxima) seeds are currently underused food ingredient, despite being a high tryptophan-rich protein source. In this study, we obtained and characterized a protein hydrolysate from defatted C. maxima seed meal, focusing on the effect of the used protease on tryptophan release. Protein hydrolysates were prepared using five different proteases and compared regarding the degree of hydrolysis (DH), free tryptophan content, hydrolysis kinetics, and potential antioxidant activity over reaction time. Protein hydrolysis using Flavourzyme resulted in the highest DH (35.6%), and free tryptophan concentration (337.9 mg/100 g), whereas hydrolysates obtained using Chymotrypsin showed the highest in vitro antioxidant activity (oxygen radical absorbance capacity [ORAC]) (371.1 mmol TE/100 g DM of protein extract). Our results show that protein hydrolysates from C. maxima seeds are a promising source of free tryptophan, with high antioxidant activity, supporting its potential as a food ingredient or for nutraceutical applications. Practical application C. maxima seeds are a promising source of free tryptophan, and its functionalization through hydrolysis showed a significant effect increasing tryptophan release and antioxidant activity, increasing its potential for ingredient or nutraceutical applications.