Microencapsulation of antioxidant phenolic compounds from green coffee

Abstract

Green coffee is a prime source of antioxidants to functional food and nutraceuticals. Arabica and Robusta varieties were screened and decaffeinated using ethyl lactate and extracted with a polar solvent to obtain chlorogenic acid (CGA) enriched green coffee extract (GCE). The physicochemical qualities (moisture, pH, particle size, and color) and bioactive compounds (total phenolics, chlorogenic acid, and caffeine) of GCE were assessed. The GCE had 12.78 ± 2.1 mg GAE g^-1 phenolics and 10.98 mg g^-1 chlorogenic acid (CGA). To improve the stability of CGA, the GCE encapsulated by spray drying using maltodextrin (MD) and skim milk (SM) as coating agent individually and in combination. Physicochemical, antioxidant properties, and biofunctionalities of microparticles were evaluated. Highest encapsulation efficiency of GCE with maltodextrin (1:1) was 86%±3 with the smaller particle size (2.3 ± 0.1 µm). Under the simulated gastric juice and bile salts solution, microencapsulation provided significantly better protection compared to non-encapsulated GCE. MGE elicits use as adjuvant/supplements in food, fortified for nutraceuticals and pharmaceuticals.

Keywords: Antioxidant; biopolymers; green coffee; in-vitro gastrointestinal studies; microencapsulation.