Physical and functional properties of roselle (Hibiscus sabdariffa L.) extract spray dried with maltodextrin-gum arabic mixtures

Abstract

Hibiscus sabdariffa L. calyces are a source of phenolic compounds which provide high antioxidant activity. The aim of this work was to improve the stability of roselle extracts by spray-drying using combinations of maltodextrin (MD) and gum arabic (GA) as carrier agents, preserving the antioxidant compounds. MD:GA matrices resulted in a very good option to produce roselle powders with excellent physical properties: low moisture content (<1.7g H2O/100 g d.m.) and water activity (<0.26); high glass transition temperature (42–48°C), and very high solubility (>99%). The powders showed low cohesiveness and a very good flowability. Higher GA in the matrix improved the retention of anthocyanins (171.21 ± 0.13 mg cyn-3-glu/100 g d.m.), polyphenols (465.80 ± 0.13 mg GAE/100 g d.m.) and the antioxidant capacity (95.5 ± 0.82 mmol Trolox/kg d.m.). These powders could be applied as an instant “agua de jamaica” product, giving an easy preparation method for the consumer. The antioxidant capacity of the reconstituted roselle powders was similar to those of mango and pineapple freshly squeezed juices, suggesting that this beverage could provide a relevant functional input. Practical applications: Mexico is one of the largest consumers among Latin American countries of a refreshing infusion called “agua de jamaica” made from Hibiscus sabdariffa. The main drawback of this beverage lies in its short shelf life. In this work, we showed that spray-drying proved to be an adequate process for obtaining an alternative product that presents higher stability while retaining the functional characteristics of the original drink.