Hibiscus ( Hibiscus Sabdariffa L.) extracts freeze-dried and encapsulated by ionic gelation: an approach for yogurt application

Hibiscus ( Hibiscus sabidariffa L.) is a flower known for its amount of anthocyanins that can be used as a natural dye for food application. The objective of this paper was to perform two extraction techniques (thermosonication and conventional extraction) from hibiscus, followed by freeze-drying and encapsulation by ionic gelation, and evaluate the application of the best sample in yogurt. The encapsulated samples (obtained by thermosonication and conventional extraction) showed longer half-lives and less color variation (ΔE), indicating that they are more stable (especially in the absence of light) and thus were chosen for application in yogurt. Both encapsulated samples were suitable to yogurt produced, and did not presented significative difference between each in major the evaluated characteristics in yogurts. The yogurt with the capsule obtained by the termosonification process showed to be darker (lower brightness value) and with a greater tendency towards red. Therefore, is more indicated for this type of product, and potentially recommended for use as a natural food dye.