Encapsulation of camu-camu extracts using prebiotic biopolymers: Controlled release of bioactive compounds and effect on their physicochemical and thermal properties

Abstract

Camu-camu (Myrciaria dubia [H.B.K] McVaugh) is a Amazonian fruit rich in ascorbic acid and phenolic compounds, and has been attracting great interest from the food, pharmaceutical and nutraceutical industries due to its potential health benefits. The bioactive compounds from camu-camu are considered sensitive and unstable, resulting in nutritional losses and impairment of its commercialization and export. For this reason, the camu-camu extract (pulp and peel) was subjected to microencapsulation by spray drying process using maltodextrin (MD), inulin (IN), and oligofructose (OL) as carrier agents. Lyophilized in natura camu-camu extract (CEL) was also evaluated. Thus, physicochemical and thermal properties and controlled release at different temperatures (25 °C and 35 °C) were investigated. In contrast with the IN and OL microparticles, the MD microparticles showed lower density and hygroscopicity, besides greater thermal stability, antioxidant activity, and retention of ascorbic acid and anthocyanins. FTIR spectra allowed the qualitative evidence of encapsulation of the bioactive compounds from the camu-camu extract. The highest percentage of volatile compounds was observed in IN microparticles, followed by OL and MD microparticles. The major group of compounds identified in CEL were terpenes (88%). The Korsmeyer-Peppas mathematical model allowed to describe the controlled release behavior of ascorbic acid and anthocyanins in the powder extracts. The controlled release followed a Fickian diffusion mechanism (n ≤ 0.43). The increase of temperature from 25 °C to 35 °C influenced on the release of bioactive compounds in all treatments, showing greater release for MD microparticles. The encapsulating materials were considered effective for the production of camu-camu extract powder, contributing to the better use of this Amazonian fruit. In addition, the encapsulation process increased the stability of its bioactive compounds, representing a tool to facilitate their incorporation in several matrices to act as antioxidant and coloring agents, as well as nutraceutical.