Behavior of inulin, polydextrose, and egg albumin as carriers of<i>Bougainvillea glabra</i>bracts extract: Rheological performance and powder characterization
Fernanda Kuhn, Eduarda Silva de Azevedo, Caciano Pelayo Zapata Noreña
Abstract
Bougainvillea glabra bracts extract was encapsulated by spray-drying and freeze-drying, using polydextrose, inulin, and egg albumin as carrier materials. All dispersions prepared before the drying process exhibited shear-thinning behavior of pseudoplastic fluids. The spray-dried powder containing inulin as carrier material showed the lowest hygroscopicity, while the highest solubility values were obtained for all powders containing polydextrose. Polydextrose as carrier material and spray-drying provided the highest retention of total phenolic compounds (94.92%), while inulin and freeze-drying showed the highest betalains retention (78.20% for betacyanins and 51.15% for betaxanthins) as well as antioxidant capacity (78.63%). All powders presented thermal stability up to 200°C according to the TGA assays. The FTIR analysis suggested the effective encapsulation of bioactive compounds from B. glabra bracts showing similar bands among the extract and B. glabra powders, with physical interactions between the bioactive compounds from the extract and carrier materials. Practical applications Bougainvillea glabra bracts are a still underexploited source of betalains and phenolic compounds. Spray-drying and freeze-drying encapsulation combined with polydextrose, inulin, and egg albumin as carrier materials may be used to improve the stability of bioactive compounds from B. glabra bracts extract. Therefore, the encapsulation of B. glabra bracts extract represents an alternative to potentialize its use as a food coloring and as a functional product in foods. In addition, polydextrose and inulin may offer additional benefits to consumers due to its prebiotic nature, while egg albumin contains many important functional proteins.