Anthocyanins from jussara (Euterpe edulis Martius) extract carried by calcium alginate beads pre-prepared using ionic gelation

Abstract

In order to take advantage of the functional properties of the jussara (Euterpe edulis Martius) extract, this study aimed at producing alginate hydrogel beads by ionic gelation process to carry jussara extract, increase its stability and to protect the anthocyanins from environmental conditions that interfere in stability and color of these compounds, such as the pH of the medium. Anthocyanins encapsulation from extract occurred by adsorption technique using blank alginate beads. Ionic gelation method was combined with complexation process using chitosan, whey protein concentrate or gelatin. Complexation technique using cationic polymers was effective in protecting these pigments during refrigerated storage. Gel strength of the hydrogel beads and anthocyanins retention was influenced by zeta potential and apparent viscosity of the materials used in the coating process. Chitosan presented higher zeta potential (+57.1 ± 2.0 mV) and apparent viscosity (0.013 ± 0.000 Pa.s) values and the beads coated with this material showed higher monomeric anthocyanins retention (8.4 ± 0.2 mg of cyanidin 3-glucoside equivalent/g of dry bead) than those coated with whey protein concentrate and gelatin (6.6 ± 0.3 and 5.2 ± 0.4 mg of cyanidin 3-glucoside equivalent/g of dry bead, respectively). Ionic gelation encapsulation process led to the formation of hydrogel beads containing anthocyanins, thus enabling the release profile of the compounds at specific pH conditions, such as the intestinal fluid.