Preparation of Natural Blue Ferrous Anthocyanin Chelate and Its Stability

Abstract:

To alleviate the scarcity of natural blue pigment resources, anthocyanin-Fe²⁺ chelates were prepared using anthocyanin and Fe²⁺ salt in this study. Their feasibility as natural blue pigments and the color stability in a simulated beverage system (pH 3.0) during storage and under thermal treatment were evaluated. The results showed that the anthocyanin-Fe²⁺ chelate prepared with an anthocyanin:Fe²⁺ molar ratio of 1:350 was bluish violet, and its degradation followed the first-order reaction kinetics (R² >0.80). Under dark storage for 14 days, the color stability of anthocyanin-Fe²⁺ chelate at 4 ℃ was better than that at 20 ℃. The half-life and activation energy values of anthocyanin-Fe²⁺ chelate were improved by adding xanthan gum, which slowed down the degradation and blue color loss. However, the thermal stability of anthocyanin-Fe²⁺ chelate was poor during thermal treatment, and its degradation was accelerated at high temperature. In conclusion, anthocyanin-Fe²⁺ chelates, as natural edible blue pigments, have good application potentials and exhibit good stability in low-temperature food processing and storage.