Enzymatic hydrolysis of hard-to-cook bean (Phaseolus vulgaris L.) protein concentrates and its effects on biological and functional properties

Summary: Inadequate postharvest handling and storage under high temperature and relative humidity conditions produce the hard-to-cook (HTC) defect in beans. However, these can be raw material to produce hydrolysates with functional activities. Angiotensin I-converting enzyme (ACE) inhibitory and antioxidant capacities were determined for extensively hydrolysed proteins of HTC bean produced with sequential systems Alcalase-Flavourzyme (AF) and pepsin-pancreatin (Pep-Pan) at 90 min ACE inhibition expressed as IC₅₀ values were 4.5 and 6.5 mg protein per mL with AF and Pep-Pan, respectively. Antioxidant activity as Trolox equivalent antioxidant capacity (TEAC) was 8.1 mm mg^-1 sample with AF and 6.4 mm mg^-1 sample with Pep-Pan. The peptides released from the protein during hydrolysis were responsible for the observed ACE inhibition and antioxidant activities. Nitrogen solubility, emulsifying capacity, emulsion stability, foaming capacity and foam stability were measured for limited hydrolysis produced with Flavourzyme and pancreatin at 15 min. The hydrolysates exhibited better functional properties than the protein concentrate.