Microencapsulates of Stenocereus pruinosus Fermented Juice and Their Bioactive Compounds Using Maltodextrin, Gum Arabic, and Mesquite Gum as Carrier Agents

Abstract

Pitaya (Stenocereus pruinosus) is a Mexican endemic and highly nutritive fruit, but it is very perishable. Juice contains high amounts of beneficial compounds, especially betalains; however, the viscosity, due to the mucilage, limits its use as pigment in foods. In order to obtain the pitaya pigments to be encapsulated, a simplex-lattice-design was used. Pitaya fermented juices were mixed with mesquite gum (MG), gum arabic (GA), maltodextrin (MDX) or their combinations (5% w/v) and then encapsulated by spray drying at an inner temperature of 160℃. Microcapsules were analyzed in color, bioactive compounds and some physicochemical characteristics. The results showed that three single agents and their combinations (binary and ternary) allowed the obtention of powders. The use of the simplex lattice design revealed the differences in the combination of carrier agents for encapsulation. All yields varied in the range of 64-84%. All powders had moisture content below 6% and water activity around 0.208. Powders showed a pale-red color (Hue and Chroma around 16 and 32, respectively). Powders with MG and GA had the highest red index values. The MG-GA combination retained the higher amount of betalains (3.28± 0.09 mg of total betalains/g powder, particularly betaxanthins). The phenolic compounds content of powders ranged from 8.01-10.77 mg Gallic acid equivalents/g powder and a maximum antioxidant activity of 15.05 mg Trolox equivalents/g powder, particularly the ternary blend (MG-GA-MDX). The antioxidant activity was dominated by other phenolic compounds rather than betalains. Microencapsulated pigments from red pitaya could be used as natural colorants in the food industry. However, further studies should be performed to estimate the potential use of powders as colorants in food systems.