The impact of enzymatic hydrolysis using three enzymes on the nutritional properties of a chickpea protein isolate

Abstract Background and objectives Enzymatic hydrolysis has shown potential for improving the functional properties of pulse protein products; however, this process may also result in modified nutritional properties. Several studies concerning this topic have already been performed; however, in many cases these studies focus either on a single enzyme, or a single level of hydrolytic treatment. The goal of this study was instead to analyze a chickpea protein isolate (CPI) hydrolyzed under a variety of conditions, in an attempt to better understand any emergent relationships present. To achieve this, three different proteases (trypsin, pepsin, and papain), and three levels of hydrolysis (DH 5%, 10%, and 15%), that is , nine enzymatically treated CPI preparations, were used to generate protein hydrolysates. They are then tested for levels of four selected bioactive compounds (trypsin and chymotrypsin inhibitory activity, total phenolics, and tannins), as well as limiting amino acid score (LAS), in vitro protein digestibility (IV‐PD), and in vitro protein digestibility‐corrected amino acid scores (IV‐PDCAAS). Findings Increasing degree of pepsin and papain hydrolysis led to progressive decreases in trypsin inhibitory activity. Hydrolysis with all enzymes led to decreases in chymotrypsin inhibitory activity. Total phenolic contents exhibited little change following hydrolysis. Tannins could not be detected in any of the protein isolates. IV‐PD did not change following hydrolysis. Tryptophan was the most limiting amino acid in the untreated isolate, following hydrolysis cysteine + methionine also became increasingly limited. IV‐PDCAAS scores generally declined following enzymatic treatments. Conclusions Hydrolysis of <5% DH resulted in minimal negative effects to the protein quality of a CPI. CPI products hydrolyzed to more than 5% DH should be fortified with sulfur containing amino acids for optimal protein nutrition. Significance and novelty A total of nine distinct enzyme treatments were compared with respect to the nutritional properties of a chickpea protein material, showing low hydrolysis can improve the nutritional properties of CPI.