Properties of dark chocolate enriched with free and encapsulated chlorogenic acids extracted from green coffee

Abstract

To increase the functionality of dark chocolate, chlorogenic acids extracted from green coffee were added in free or encapsulated forms at different concentration (10, 20, 30, 40 and 50 mg/5 kg of free chlorogenic acids and equal quantity of encapsulated form). The extraction of chlorogenic acids was carried out by maceration of ground green coffee beans in distilled water (30 min at 80 °C), then, cooling, filtration and adsorption by active carbon were done. The final step was filtration and desorption from active carbon and rotary drying (at 60 °C and 120 rpm). Encapsulation of chlorogenic acids was done by coacervation of pectin and gelatin. For quality assessment, several analysis on chocolate samples were performed included color index and melting behavior by Differential Scanning Calorimeter. Flow behavior of the chocolate samples melted at 40 °C was determined using stress or strain controlled rheometer. The microstructure of the chocolate samples was analyzed by Scanning Electron Microscope technique at 500-1000x magnification. Particle size distribution and sensory evaluation was also performed. Results showed addition of free and encapsulated forms of chlorogenic acids decreased Tonset, Tpeak and ΔH of dark chocolate. Casson viscosity increased in the case of addition chlorogenic acids. Color indexes of chocolate samples were influenced by addition of chlorogenic acids. Particle size distribution decreased with addition of free form and increased when encapsulated form was added. Sensory characteristics were also influenced by chocolate formulation and samples included encapsulated chlorogenic acids exhibit better sensory properties than samples enriched with free form.