In vitro study on digestion of pumpkin oil cake protein hydrolysate: Evaluation of impact on bioactive properties

Abstract

In this work, a simulated gastrointestinal digestion of pumpkin oil cake protein hydrolysate prepared by alcalase (AH) was studied to evaluate the impact of the main gastrointestinal proteases on its antiradical and angiotensin I-converting enzyme (ACE) inhibitory activity. The in vitro digestion was performed in a model system under optimized reaction conditions, first by pepsin and then with α-chymotrypsin and trypsin, simultaneously. The treatment with the gastrointestinal proteases led to a significant increase of the degree of hydrolysis, up to 55.95 ± 3.1% in the final digest. After the digestion, the 2,2-azinobis3-ethylbenzo-thiazoline-6-sulphonic acid radical cation activity of AH was increased from 7.59 ± 0.1 to 10.25 ± 0.3 mM trolox equivalent antioxidant coefficient/mg (p < 0.05), while the ACE inhibitory activity was not affected, being 74.29 ± 1.25% (IC50 = 0.404 ± 0.014 mg/ml) (p>0.05) in the final digest. These results showed an advantage of AH to increase the antiradical and resist ACE inhibitory activity during digestion by main gastrointestinal proteases, appearing as promising bioactive food ingredient. © 2012 Informa UK, Ltd.