Association of antioxidant monophenolic compounds with β-cyclodextrin-functionalized cellulose and starch substrates

Polysaccharide substrates loaded with antioxidant and antimicrobial compounds, effectively protected by cyclodextrin moieties, can be a long-lasting solution to confer certain properties to fabrics, paper and other materials. beta-Cyclodextrin was attached to alpha-cellulose, bleached pulp and starch by a two-step esterification with a tetracarboxylic acid. The resulting derivatives were characterized by spectroscopy, thermal degradation analysis and capability of phenolphthalein inclusion. The carriers, containing between 89 and 171 mu mol of beta-cyclodextrin per gram, were loaded with carvacrol, cuminaldehyde, cinnamaldehyde and hydroxytyrosol. From a stoichiometric addition, the percentage of compound retained ranged from 49% (hydroxytyrosol in pulp-cyclodextrin) to 92% (carvacrol in starch-cyclodextrin). Finally, the release rate to aqueous ethanol was measured over eight days and fitted to kinetic models. From the analysis of the mean dissolution time, it can be concluded that inserting beta-cyclodextrin units enhanced the long-term holding of phenolic active compounds in carbohydrate matrices.

Automated summary

The study demonstrates the long-lasting protection of antioxidant and antimicrobial compounds loaded on polysaccharide substrates, effectively preserved by cyclodextrin moieties, to confer specific properties to fabrics, paper and other materials. The insertion of beta-cyclodextrin units enhances the long-term retention of phenolic active compounds in carbohydrate matrices, with a higher percentage of compound retained when using certain substrates. The release rate of these compounds over time can be measured and fitted to kinetic models to predict their behavior in aqueous ethanol.