Avaliação da atividade antioxidante do extrato de beterraba (Beta vulgaris) na forma alcoólica e microencapsulada com maltodextrina

Abstract

The beet has important health promoting effect, in its composition presents bioactive compounds as betalains and phenolic compounds, both recognized for having high antioxidant power. The betalains are nitrogenous and water-soluble dyes classified into betacyanins (red-violet color) and betaxantinas (yellow-orange color). These pigments are indicated as an alternative to bioactive natural dyes, however due to the instability to factors linked the food processing techniques are still not used on a large scale in the industry. Accordingly, a microencapsulation technique is shown as a possibility of increasing the presence of compounds in addition to facilitating handling during use. This study aimed to get the beet extract (Beta vulgaris) and evaluate betalains content, phenolics, flavonoids and antioxidant activity of the extract before and after microencapsulation spray (spray dryer), using as carriers maltodextrins of equivalent dextrose agents (DE) 15 and 20. The antioxidant activity was evaluated through the analysis of ABTS, DPPH and Cu2 + chelating ability, the betalains, phenolic and flavonoid contents were also evaluated. The beet alcohol extract gave better performance for all the antioxidant analyzes and theoretical bioactivities had no present of study, in comparison with the results obtained in the beet extract, in natura, and remained in the pH range of the product of the betalaínas, after the alcoholic extraction. These results demonstrated that the extraction of the bioactives present in the beet by the solid-liquid extraction process with 70% ethanol was efficient. Maltodextrins of equivalent dextrose of 15 and 20 were efficient for preservation of betalains and antioxidant activity. The microencapsulated powder with maltodextrin of 15 DE presented a higher yield in the atomization process compared to the powder microencapsulated with maltodextrin of 20 DE, presenting a better applicability for the microencapsulation of the alcoholic beet extract by spray drying. Both microencapsulated samples showed high retention of betalains and, therefore, the antioxidant activity and the dyeing power provided by the betalain pigments present in the extract were maintained, evidencing that the microencapsulation technique is a viable process for the protection of these pigments.