A novel approach for encapsulation of black raspberry anthocyanins by complex coacervation method using gelatin and gum Arabic as wall materials

In this work, we microencapsulated black raspberry extracts by double emulsion technique prior to complex coacervation using gelatin and gum Arabic to diminish the instability of their anthocyanins (ANCs), particularly under harsh conditions. The coacervation process wasinvestigated as afunction of gelatin, gum Arabic and the core material concentrations at ratios of 1:1:0.5and 1:1:1, the concentration of polymer solutions (5.0 and 7.5%, w/v) as well as pH (3.5, 4.0,4.5 and 5.0). Subsequently, morphology, particle size, moisture, solubility, hygroscopicity, loading capacity, stability, Fourier transform infrared spectroscopy (FTIR) were evaluated. The microcapsules presented the lower moisture, hygroscopicity and solubility values as comparing the free form of ANCs. They showed the average sizes ranging from 45.25±0.97 to 87.92 ± 7.18 μm and high loading capacity (33.05 ± 0.31 to 41.72±0.30%). According to the HPLC results, the selected method significantly increased the stability of ANCs up to 36% after 2 months of storage at 37 ± 2◦C. FT- IR spectra confirmed the occurrence of coacervation process. Furthermore, the selected optimal microcapsules revealed intense red color over the time of storage, implying the effectiveness of the method chosen to preserve anthocyanins.