Biofunctional properties of bioactive peptide fractions from protein isolates of moringa seed (Moringa oleifera)

Moringa oleifera (Moringaceae) is a specie of significant importance because of its multiple nutraceutical properties, that has led to increase in its consumption. The seeds contain a high percentage of protein (37.48%). However, little is known about the bioactive properties of these proteins and peptides, especially those generated by enzymatic hydrolysis. The objective of this study was to evaluate the biofunctional properties of total hydrolysates (TH) and peptide fractions from protein isolates of moringa seeds. Isoelectric protein isolates were prepared and TH were obtained by digestion with trypsin, chymotrypsin and pepsin-trypsin for 2.5 and 5 h. TH were fractioned by ultrafiltration (UF) with a 10 kDa membrane to generate the peptide fractions. In all treatments, the antioxidant capacity was significantly higher in peptide fractions > 10 kDa with 5 h of hydrolysis. The results showed that the fraction > 10 kDa of pepsin-trypsin digested for 5 h presented a better Angiotensin Converting Enzyme inhibition (ACE-I) activity with an IC₅₀ of 0.224 μg/μl. Also, antidiabetic activity was enhanced in pepsin-trypsin treatment with 5 h of hydrolysis showing an IC₅₀ of 0.123 μg/μl. Finally, this study showed that hydrolysates of moringa seed proteins had excellent in vitro nutraceutical potential.