Interaction between oyster peptides and anthocyanins: Stability improvement, structure changes and α-amylase and α-glucosidase inhibition effect

The purpose of the present work was to create the oyster peptides (OPs)-black soybean seed coat anthocyanins (ACNs) complexes, investigate their stability improvement, interactions and α-amylase and α-glucosidase inhibition effect. The stability analysis results showed that OPs could effectively improve the stabilities (solution, light and pH stability) of ACNs. Interaction characterization demonstrated that the interaction between ACNs and OPs primarily involved hydrogen bonding, electrostatic forces, and hydrophobic interactions. OPs-ACNs complexes possessed significant inhibitory activity against α-glucosidase (88.6% when 3 mg/mL, K ic 1.05 mg/mL) and α-amylase (64.68% when 3 mg/mL, K ic 0.04 mg/mL and K iu 0.07 mg/mL). Moreover, the enzyme inhibition kinetic analysis indicated that ACNs-OPs exhibit competitive inhibition towards α-glucosidase and mixed inhibition towards α-amylase, with competitive inhibition being the predominant type. Altogether, the results suggested that OPs complex with ACNs could effectively improve ACNs’ stability and hypoglycemic effect in vitro through non-covalent interactions. • An oyster peptide (OPs)- anthocyanins (ACNs) complexes (OPs- ACNs) was fabricated. • OPs-ACNs enhanced the stabilities (solution, light and pH) of individual ACNs. • ACNs are bound with OPs through non-covalent interactions. • The inhibition pattern of OPs-ACNs against α-glucosidase was competitive inhibition. • The inhibition pattern of OPs-ACNs against α-amylase was mixed-type inhibition mode.