Anthocyanin-Based Natural Food Colorant from Fresh Waste Carnation Flower Petals: Effect of pH, Temperature, and Drying Method on its Degradation Kinetics and its Use in Ice Cream

Abstract

The carnation flowers (Dianthus caryophyllus L.) with broken stems or overgrown buds remain in the greenhouse and are discarded after all cutting operations are completed. Waste flowers are also separated while bouquets are being prepared. Therefore, this study aimed to utilize these fresh waste flowers in the production of natural food colorants. Anthocyanin extract was obtained from waste carnation flowers and turned into powder products via freeze- and spray-drying. Various properties of the powders were analyzed and statistically compared. Since degradation parameters of anthocyanins should be taken into consideration during the planning of the materials to which anthocyanin-based colorant will be added, the kinetic parameters of carnation anthocyanins were calculated at different pH (2.6, 4.0, and 6.0) and temperature (70, 80, and 90°C) values. Except for the liquid extract, the activation energies of all samples sharply decreased when the pH changed from 2.6 to 6.0. The most and least susceptible samples to the temperature elevation were freeze-dried samples at pH 2.6 and spray-dried samples at pH 6.0, respectively. Across all the data, the activation energies of the liquid extract sample at pH 2.6 and pH 4.0 were not significantly different from each other (p