Controlled release and antioxidant activity of Roselle (Hibiscus sabdariffa L.) extract encapsulated in mixtures of carboxymethyl cellulose, whey protein, and pectin

The aim of this study was to evaluate the release of phenolic compounds from Roselle extract encapsulated in binary and ternary mixtures of whey protein, carboxymethyl cellulose (CMC) and pectin. Films were formulated according to a simplex centroid experimental design and total polyphenols and antioxidant activity (FRAP and DMPD methods) were quantified in the release medium as time dependent variables. Films' weight gain was measured and swelling behavior was calculated. The data obtained correlated well with a first-order kinetic model (R-2 > 0.9). While CMC avoids the release of polyphenols and the expression of the antioxidant activity, whey protein and to a lesser extent pectin enable the release of these compounds faster and in larger amounts. Higher antioxidant activities were observed at higher concentrations of pectin and whey protein in the mixtures (80 g/100 g) combined with lower concentrations of CMC (10 g/100 g). The results obtained showed that the release of Roselle's polyphenols can be predicted by controlling the composition of the mixtures. (C) 2012 Elsevier Ltd. All rights reserved.