Adsorption behaviour of some anthocyanins by wheat gluten and its fractions in acidic conditions

Summary Some anthocyanins, both commercial delphinidin-3-O-β-d-glucoside chloride and cyanidin-3-O-β-d-rutinoside chloride (Dp3glu and Cy3rut) and extracted from plants, were adsorbed by gluten or its fractions to carry out a study that can be considered a premise to estimate the potential effect on bioavailability of anthocyanin adsorption. This process was studied by means of adsorption kinetics and isotherms. Among the parameters determining adsorption, the temperature and the pH value were evaluated. The data show that gluten and its fraction have a great adsorption capacity (about 1.0 mg g−1 of gluten). The results indicate that the structure of the anthocyanins plays an important role in their adsorption by gluten or its fractions; in fact, the adsorption kinetics show that Dp3glu is more adsorbed than Cy3rut. The isotherms of anthocyanin adsorption by gluten indicate the presence of a strong interaction between the two types of molecules. This could be an important finding to obtain functionalised-based gluten products.