Effect of gelatin and acacia gum on anthocyanin coacervated microcapsules using double emulsion and its characterization

The present study was aimed to develop a stable microencapsulated anthocyanin from black rice bran using double emulsion complex coacervation technique. Nine microcapsule formulations were prepared using gelatin, acacia gum and anthocyanin at ratios of 1:1:0.5, 1:1:0.75 and 1:1:1 respectively. The concentration of gelatin and acacia gum used were 2.5, 5 and 7.5 % w/v. Subsequently, the coacervated microcapsules were obtained at different pH (3, 3.5 and 4), freeze-dried and evaluated for their physicochemical properties, morphology, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction pattern (XRD), thermal behaviour and stability of anthocyanin. The results obtained for encapsulation efficiency of anthocyanin with high values (72.70 to 83.65 %) indicated that the encapsulation process was effective. The morphology of the microcapsule powder was analysed and exhibited round, hard, agglomerated structures and relatively smooth surface. The thermal degradation behaviour of microcapsules displayed endothermic reaction confirming the thermostability of the microcapsules where the peak ranged from 83.7 to 97.6 °C. The stability studies in terms of retention of total anthocyanin content were observed at different storage conditions; both under refrigerated condition (7 °C) and at room temperature (37 °C). The results indicated that the microcapsules obtained through coacervation can be an alternative source to develop stable nutraceuticals.