Preparation and characterization of resveratrol-loaded microcapsules with whey protein and flaxseed gum by membrane emulsification and complex coacervation methods

The study developed microcapsules by membrane emulsification and complex coacervation methods with whey protein (WP)-flaxseed gum (FG) and monodiglyceride fatty acids (MFA) to be used for resveratrol (RES) encapsulation. The effects of MFA and WP/FG ratios (1:0-1:0.15) on the properties of microcapsules were investigated. Zeta potential and infrared spectra analysis indicated the possible electrostatic attraction and hydrogen bonding between WP and FG. Fluorescence further confirmed the formation of WP/FG complex coacervates. Confocal laser scanning microscopy, X-ray diffraction and differential scanning calorimetry studies demonstrated that RES dissolved in MFA was encapsulated by the complex of WP and FG. The microcapsules exhibited an appearance of irregular flakes or blocks with folds and a high encapsulation efficiency (EE, > 96 %). MFA and FG increased the EE of RES. In vitro release study displayed that MFA and FG decreased the release rate of RES from the microcapsules. Due to the isolation effect of MFA and the wall materials, microcapsules had good photostability. The antioxidant ability of RES was enormously improved by the complexation with WP and FG. These findings provide an effective carrier to deliver polyphenols like RES and could be useful in the developments of foods and medicine.