Study on interactions of vitamin B1 with sodium dodecyl sulfate for potential food applications: Conductometric, volumetric, calorimetric and spectroscopic approach

摘要

As vitamin B1 (thiamine hydrochloride, THC) is being oxidized by food preservatives and light, therefore the advantages of surfactant micelles as protecting agent are taken into consideration in the present study. Keeping this in mind the impact of THC on the SDS micellar system has been studied by using conductance, volumetric, calorimetric and spectroscopic techniques. From conductance measurements, various parameters like critical micellization concentration (CMC), degree of dissociation (alpha) and thermodynamics of micellization (Delta G(m)(o), Delta H-m(o), and Delta S-m(o)) have been calculated. Apparent molar volume (V-Phi) and apparent molar compressibility (K-s,K-2.Phi) have been calculated from density and sound velocity measurements which have been discussed in terms of solute solute and solute-solvent interactions. The binding and partitioning of THC into SDS micelles have been studied by using UV-visible spectroscopy and calorimetric studies. Calorimetric studies have also been used to address the interactions of THC with monomers of SDS. The values of binding/partitioning constant (K), enthalpy, entropy, free energy and stoichiometry of binding have been determined in the pre-micellar and post-micellar regions from isothermal titration calorimetery (ITC). In addition, proton (H-1) NMR studies have been performed to determine the locus and orientation of THC within SDS micelles. (C) 2019 Elsevier B.V. All rights reserved.