Improvement in dispersibility, stability and antioxidant activity of resveratrol using a colloidal nanodispersion of BSA-resveratrol

Resveratrol has low aqueous stability and solubility in its native form that restricts its use in fortifying food products. The influence of bovine serum albumin (BSA)-trans-resveratrol complex on the solubility, photochemical stability and antioxidant activity of trans-resveratrol was studied using UV and fluorescence spectroscopy techniques, oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays. The results showed that resveratrol was solubilized using BSA at a molar ratio of 2.3:1 of resveratrol:BSA. FTIR and fluorescence spectroscopy techniques verified the formation of the BSA-resveratrol complex. The results of UV spectroscopy showed that the formation of the complex significantly protected resveratrol from UV-induced isomerization. The FRAP values for resveratrol-BSA were decreased compared to free resveratrol (57% in 30:30 resveratrol-BSA, 39% in 90-90 resveratrol-BSA and 25% in 300:300 resveratrol-BSA mu M concentration). ORAC assays showed an almost 3 folds decrease in antioxidant activity of resveratrol after 3 days; however, ORAC values for BSA-resveratrol complexes were not significantly changed. BSA was successfully used to improve resveratrol solubility and stability in aqueous medium. This approach may increase the daily intake of unchanged resveratrol by consumers of fortified beverages using this system.