Microencapsulation of Roasted Coffee Oil by Complex Coacervation with Gelatin/Gum Arabic Enzymatically Crosslinked

Resumo

The roasted coffee oil is a coffee industry byproduct composed by a great number of compounds including the volatiles, responsible by coffee aroma. The main objetive of the present work is the encapsulation of roasted coffee oil in enzimatically crosslinked gelatin and gum Arabic microcapsules. The microcapsules were obtained by complex coacervation. The effect of the roasted coffee oil amount used and the stirring rate on the average diameter, oil recovery and encapsulation efficiency were evaluated. The microcapsules presented average diameter up to 29.30 ± 1.28 µm with narrow size distributions. The results varied from 78.45 ± 2.47 to 100.70 ± 5.23 % (oil recovery) and 32.50 ± 3.53 to 71.00 ± 4.24 % (encapsulation efficiency). The water sorption isotherm of microcapsules was evaluated at 25 ºC and the results were fitted with the Guggenhein-Anderson-de Boer (GAB) model, presenting a R² equal to 0.9892 and “J” shape behavior. Finally, the crosslinking reaction was investigated by Fourier Transform Infrared Spectroscopy (FTIR), showing that the crosslinking reaction promoted by transglutaminase introduced a band in microcapsules spectra located at 1550 cm^-1 corresponding to the monosubstituted amide.