Encapsulation of cactus ( Opuntia megacantha ) betaxanthins by ionic gelation and spray drying: A comparative study

OTÁLORA, MARÍA CAROLINA; CARRIAZO, JOSÉ G.; OSORIO, CORALIA; NAZARENO, MÓNICA AZUCENA

FOOD RESEARCH INTERNATIONAL

ELSEVIER SCIENCE BV

Año: 2018 vol. 111 p. 423 - 430

0963-9969

The encapsulation of betaxanthins from orange Opuntia megacantha fruits was performed as a stabilisation strategy for these natural pigments. Betaxanthin-rich extract (BE) was encapsulated by two methodologies, spray drying (SD) and ionic gelation (IG). Encapsulates were obtained by using two encapsulating agents (EA), a mixture of maltodextrin-cactus cladode mucilage and sodium alginate (SA) for SD and IG, respectively. Their properties were compared with the freeze-dried cactus fruit pulp (CP) as control. Total betaxanthin content, moisture content, water activity (aw), particle size, morphology by SEM, colour parameters (CIELab), and thermogravimetric properties were analysed in the encapsulates. Additionally, the antioxidant activity, totaldietary fibre content, and pigment stability of encapsulates under two relative humidity conditions were also evaluated. The results showed that the encapsulation technique, EA concentration, and the BE/EA ratio affected the particle size and morphology, the glass transition temperature, and the mass loss of encapsulated materials.The best pigment stabilisation was obtained for the SD capsules, although both encapsulation techniques allowed improving the pigment stability in comparison with the CP taken as control. These results provided evidence that betaxanthins from Opuntia megacantha have the potential to be used as natural pigments, soluble in water, withfunctional properties for the food industry.