Antioxidant activity and stability of α‐tocopherol, resveratrol and epigallocatechin‐3‐gallate in mixture and complexation with bovine serum albumin

Abstract

SummaryLigand‐binding proteins were proposed as ideal carriers for the co‐encapsulation of bioactive compounds. Multiple compounds co‐encapsulated in food formulation may give rise to different effects on bioactivity and stability. The protein effect on the interplay between bioactive compounds was investigated for selecting suitable co‐encapsulation strategy. α‐Tocopherol, resveratrol and epigallocatechin‐3‐gallate (EGCG), as model compounds, interacted with bovine serum albumin (BSA) to form tri‐ligand complexes when added in the sequence. For ferric‐reducing antioxidant power, the mixtures of α‐tocopherol and resveratrol,α‐tocopherol and EGCG, resveratrol and EGCG were respectively additive, antagonistic and synergistic, while their ternary mixture were antagonistic. For ABTS+ scavenging capacity, all pairs were antagonistic. BSA improved FRAP of α‐tocopherol, resveratrol and EGCG mixture but decreased their ABTS inhibition. Although structural stability and antioxidant activity of resveratrol decreased when alone interacted with BSA, they were improved when α‐tocopherol and EGCG were co‐presented. Mixing the antioxidants improved their stability and the complexation with BSA can further stabilise them. BSA could thus be a suitable carrier for co‐encapsulation/protection of α‐tocopherol, resveratrol and EGCG in functional foods.