Protective effect of β-lactoglobulin against heat induced loss of antioxidant activity of resveratrol

Resveratrol exhibits many health benefits; however, low water-solubility and instability under processing conditions such as heating can be some of the main challenges for its processing and formulation. Here the complexation of β-lactoglobulin (β-Lg) with resveratrol was investigated to improve its solubility and stability. The solubility of resveratrol in water was determined as 7 mg/100 ml. Resveratrol-β-Lg nanoparticles (181.8 nm) were produced at pH 6 and 75 °C for 45 min. Heating resveratrol solutions at 75 °C for 45 min resulted in isomerization of resveratrol and reduced antioxidant activity. However, resveratrol-β-Lg nanocomplexes which had undergone the same heat treatment exhibited improved antioxidant activity. Heating under pasteurisation conditions led to similar results and both native β-Lg and nanoparticles exhibited a protective effect against heat-induced chemical changes in resveratrol, resulting in enhanced antioxidant activity. Fluorescence measurements revealed strong interactions of resveratrol with both native protein and nanoparticles.