MICROENCAPSULATED WHOLE GREEN COFFEE FRUIT: DEVELOPMENT AND STABILITY STUDY

This research explores the spray-drying microencapsulation of whole green coffee fruit extract (GCFE) with high level of phenolic acids standardized in 5-O-caffeoylquinic acid (5-CQA) one of the best-documented compound with reducing capacity. The optimal conditions for microencapsulation by spray drying were selected using response surface methodology (RSM) and a central composite rotational design (CCRD) to evaluate the effects of replacing part of the gum Arabic (GA) by maltodextrin (MD) as the carrier material and of the ratio of concentrated extract: carrier agent dispersion (w/w). These effects of the independent variables were evaluated on the encapsulation efficiency, process yield, 5-CQA retention, surface morphology by scanning electron microscopy, particle size distribution measured by laser diffraction using a Malvern Mastersizer X (Ver. 2. 15) fitted with a 45mm lens, and microencapsulated GCFE stability at 40ºC for 180 days compared to non-encapsulated GCEF powder. The stability was monitored assessing the reducing capacity using Folin-ciocalteau method and monitoring the content of 5-CQA, caffeic acid, caffeine and trigonelline by HPLC-DAD-MS. The encapsulation efficiency ranged from 98.3 to 99.7 % and 5-CQA retention ranged from 52 to 78% among microparticles obtained. The loss of reducing capacity was greater on the non-encapsulated dried extract which showed significant difference (p>0.05) compared with the GCEs microencapsulated, however the loss of reducing capacity of micro-particles didn’t show significant difference (p>0.05) between themselves. The RSM showed that microparticles formulated with a greater MD percentage in the carrier dispersion and a smaller concentrated extract to carrier dispersion ratio, showed greater stability in relation to the caffeic acid content. The highest process yield was obtained when 80% of the GA was replaced by MD and when the ratio of concentrated extract to carrier agent dispersion was 1:3.5 (w/w). Both, microencapsulated and non-encapsulated GCFE, showed a good stability during the accelerated stability study.