Application of peptidases from Maclura pomifera fruit for the production of active biopeptides from whey protein

•Peptidases from latex of Maclura pomifera fruits hydrolyse bovine whey proteins.•Prepared whey hydrolysates display antioxidant and ACE-inhibitory activities.•This product could be used as ingredient in preparation of functional foods.

A crude extract containing serine peptidases, was prepared from latex of Maclura pomifera fruits. Peptidases were isolated by precipitation with one volume of ethanol with a yield of 5.4 ± 0.4 Ucas per milligram of protein. This extract was used for hydrolysis of bovine whey proteins at 45 °C and pH 6.5. Proteolytic activity was 99% inactivated after 5 min of heat treatment (100 °C). Major whey proteins degradation profile was analysed by tricine SDS-PAGE. After 180 min of hydrolysis alpha-lactalbumin (α-LA) and beta-lactoglobulin (β-LG) were almost completely degraded. Hydrolysis degree was 31.3 ± 1.7% at 180 min of reaction and the peptides produced that were smaller than 3 kDa were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC). Angiotensin-converting enzyme (ACE) inhibitory activity and antioxidant capacity were detected in the hydrolysates and IC50 values for 180 min of hydrolysis were 0.53 ± 0.02 and 4.44 ± 0.44 mg/ml, respectively. One peptide sequence deduced from peptide masses in the 180 min filtered hydrolysate, coincided with an ACE-inhibitory peptide reported by other author. The results support the conclusion that, by the presence of ACE-inhibitory and antioxidant peptides, it would be possible to use these whey protein hydrolysates for functional food manufacturing.