Encapsulation of Blackberry Anthocyanins by Thermal Gelation of Curdlan

Blackberry shows an attractive color due to the presence of anthocyanins; however the use of these pigments as natural colorant is difficult since some external agents, specially pH>3, cause their discoloration. On the other hand, encapsulation techniques have been widely used in the industry to protect active ingredients. The aims of this study were to establish the encapsulation conditions of anthocyanins from blackberry, to evaluate the capsules characteristics, as well as the anthocyanins release. Three polysaccharides (curdlan, pectin and sodium alginate) were evaluated as wall material to obtain capsules by gelation. Curdlan was chosen since it was the only gum capable to form hard gel under low pH value. The capsules showed spherical form and multinucleated appearance, and encapsulation efficiency ranged from 80.3 to 96.7%. The release curves followed first order kinetics, with a strong burst effect, 80 to 100% of the anthocyanins released in solution at pH 1 after 20 min.