The modification of the molecular and thermodynamic parameters of the low-DE potato maltodextrin in an aqueous medium through the interactions with anionic small-molecule surfactants

We present the modification of the molecular and thermodynamic parameters of the low-DE (DE <3; where DE is the dextrose equivalent) maltodextrin in an aqueous medium that is induced by the interactions with anionic surfactants over a wide range of the surfactant concentrations both below and above their critical micelle concentrations. As the main objects of our investigation we have chosen the industrially important low-DE maltodextrin (Paselli SA-2, DE=2) and the anionic surfactants, SSL and CITREM, which represent generally the mixtures of the esters of the stearic and palmitic acids with a lactic acid or a citric acid, respectively (i.e., these surfactants have the close lengths of the hydrocarbon “tails”, but are different in chemical structure of polar “heads” (charge, size)). Measurements have been made by static and dynamic multiangle laser light scattering of the weight—average molar mass (Mw); the radius of gyration (RG) and the hydrodynamic radius (Rh), as well as their ratio (ρ=RG/Rh), reflecting the specific architecture of the scattering particles; and the thermodynamic affinity for an aqueous medium (the second virial coefficient (A2)) of the maltodextrin+surfactant complexes in an aqueous medium. The pronounced maltodextrin association, which is attended with the change in both the shape of the maltodextrin particles and hydrophilic/lipophilic balance of the maltodextrin molecular properties, has been found as a result of the maltodextrin modification induced by the interactions with the surfactants. The revealed correlations between the light scattering data and the values of the intrinsic viscosity allowed to get a more understanding of the structural peculiarities of the surfactant-modified maltodextrin associates formed in an aqueous medium. In addition, the plausible contribution of the specific character of the maltodextrin–surfactant interactions into the way of the maltodextrin modification in an aqueous medium has been found using the mixing calorimetry data.