Abstract

An alcalase-catalysed porcine placenta hydrolysate (PPH) with a 30% degree of hydrolysis was fractionated using two cycles of ultrafiltration (UF) with molecular weight cut-offs of 100 kDa and 30 kDa to search for novel bioactive peptides. The permeate of the 30 kDa UF (UF4) demonstrated superior radical scavenging activities (DPPH^•/ABTS^•+), ferric-reducing power, β-carotene bleaching inhibitory activity, nitric oxide scavenging activity, angiotensin-converting enzyme inhibition and anti-α-amylase/α-glucosidase activity with high antioxidant stability in an in vitro gastrointestinal tract model system. The UF4 fraction was rich in hydrophobic amino acids (e.g. valine, isoleucine, alanine, leucine and proline). The first five amino acid sequences identified in the UF4 fraction were LSSPATLNSR, ASISLPR, ILLEVNNR, ESLITLIEK and QPLLLDDR, with molecular weights ranging from 760 to 2682 Da. Based on the findings, the UF4 fraction isolated from crude PPH can be developed as a novel bioactive ingredient in functional foods with the potential for scale-up and economic feasibility.