Preparation, Characterization and Storage Stability of Vitis davidii Foex. Anthocyanin Microcapsules with Tannin as Co-pigment

In this study, co-pigmentation with tannin combined with microencapsulation was used to improve the stability of Vitis davidii Foex. anthocyanin. Anthocyanin microcapsules were prepared by vacuum freeze drying using maltodextrin with different dextrose equivalent (DE) values as the wall material. The results showed that the co-pigmented anthocyanin microcapsules with maltodextrin DE12 had the highest encapsulation efficiency of (99.23 ± 0.31)% and the best hygroscopicity and thermal stability. Scanning electron microscopy (SEM) showed that the surface morphology of all four microcapsules was glassy structure. The co-pigmented anthocyanin microcapsules had higher L* and a* values but lower b* value than the unco-pigmented ones. Differential scanning calorimetry (DSC) analysis showed that the co-pigmented anthocyanin microcapsules with maltodextrin DE12 had higher thermal denaturation temperature and thermal stability. Fourier transform infrared spectroscopy (FTIR) confirmed successful microencapsulation of co-pigmented anthocyanin with maltodextrin. The co-pigmented anthocyanin microcapsules with maltodextrin DE12 had good sustained release performance and strong antioxidant capacity. After simulated gastric digestion, the percentage of anthocyanins released from the microcapsules was only (56.84 ± 0.02)%. After simulated intestinal digestion, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the microcapsules was (50.15 ± 0.38)%. Moreover, the degradation kinetics of the microcapsules followed first-order kinetics model and the microcapsules had good storage stability. Microencapsulation could effectively reduce the loss of anthocyanins during the pasteurization of V. davidii Foex. grape juice.