Hibiscus sabdariffaL. confesctionery gels,in vitrodigestion, antioxidant activity and phenolic compounds quantification: a nutraceutical application

Abstract

Summary Dehydrated Hibiscus sabdariffa (Roselle) is usually used as the raw material of popular beverages, where the exhausted calyx, still rich in polyphenols and fibre, is discarded. The aim of the present study is to evaluate the possibility of adding Roselle's whole calyx to a confectionery product elaborated with gelatin, quantifying the concentration of released polyphenols (Folin–Ciocalteu) during an in vitro digestion and the expression of antioxidant activity [Ferric reducing antioxidant power (FRAP) and N,N‐dimethyl‐p‐phenylenediamine dihydrochloride (DMPD)] during this process. Results show that hardness and elongation of Roselle‐gelatin gums respond to a quadratic model where single components and binary mixtures show significant contributions to hardness and elongation behaviour respectively. Ten grams of Roselle‐gelatin gum express a higher antioxidant activity (FRAP) than 250 mL of the infusion prepared by a traditionally procedure. A significant proportion of the radical scavenging (DMPD) activity could have been lost during the elaboration process of the gums, and although more studies should be done, a hypothesis explaining this effect is included.