Porous gelatin microspheres for high loading and improved stability of anthocyanins: Serving as antioxidant factors and food freshness indicators

Porous gelatin microspheres (PGMs) are effective means to achieve controlled release and rapid functional response of anthocyanins (ANCs). In this study, PGMs were developed by the calcium carbonate template method, which had a surface and internal porous structure. Subsequently, the loading of ACNs occurred at pH = 4 driven by the electrostatic interaction between positively charged PGMs and negatively charged ACNs, and the maximum loading was 353.08 ± 0.94 mg_ACN/g_PGMs. In addition, ACN@PGMs could also realize the long-term controlled release of ACNs, significantly delayed the degradation rate of ACNs and increased the possibility of long-term antioxidant activity of ACNs. Meanwhile, the stability experiment of storage results showed that the degradation rate of ACNs under light and humidity conditions was 56.656 ± 0.209% after 16 days, while the degradation rate of ACNs within ACN@25PGMs was only 49.239 ± 0.490%, significantly improving the storage stability of ACNs. Finally, ACN@PGMs had excellent ammonia responsiveness and the color change (from purple to yellow) could be seen by the naked eye. This provided a basis for the subsequent application of ACN@PGMs as antioxidant factors and food freshness indicators in the food field.