Characterisation of beta‐lactoglobulin/sodium alginate dry films

Abstract

Optimum beta-lactoglobulin/sodium alginate dry films (β-LG/SA(S)) formed from casting solutions containing β-LG 1.25% (w/v) and SA 1% (w/v) showed appropriate characteristics to be easily handled. SEM micrographs showed a less homogeneous microstructure of this films respect to sodium alginate dry films used as control (SA(F)). Tensile strength of 18 MPa and an elongation value of 5% were obtained for β-LG/SA(S). DSC thermograms did not demonstrate changes in thermal properties of SA in presence of β-LG. Studies based on fluorescence quenching by acrylamide did not show variations in the tertiary structure of β-LG when β-LG/SA(S) were dissolved in an aqueous environment. In addition, binding properties of the protein were similar to the native one when an alquilsulfonate compound was used as ligand. The maintenance of native binding properties of β-LG after the films’ dissolution would allow the development of new carriers for food bioactive compounds based on β-LG/SA(S) dry films.