Natural pigment extraction optimization from coffee exocarp and its use as a natural dye in French meringue.

This study aimed to optimize the pigment extraction process for coffee exocarp and to evaluate its coloring effect on French meringue. The anthocyanins were determined with the differential pH method and the process was optimized with the response surface methodology. The solvent concentration (SC) and solid solvent ratio (SSR) had a significant effect on the anthocyanin content and surface color of the coffee cherry extracts. The optimal extraction conditions 60% SC and 25% SSR resulted in the highest concentration of anthocyanins (0.145 mg cyanidin 3-glucoside/g of coffee fresh exocarp). For the French meringue, the 3% extract concentration had the smallest total color difference (ΔE), as compared to the control, evidencing the potential of coffee exocarp dyes in place of synthetic dyes in the manufacture of French meringue.