Physicochemical study of dietary fiber methylcellulose and human intestinal bile salt micellar aggregates

Abstract

The cellulose ether and bile salt mixed systems have a potential to alter the lipid digestion. The basic understanding of the aggregation process, interaction, and physicochemical properties of cellulose ether and bile salt is an essential topic of study. In this work, the interaction between simple dietary fiber methylcellulose (MC) and bile salt sodium deoxycholate (NaDC) has been studied using UV-Vis absorption, steady-state fluorescence intensity, fluorescence quenching, conductivity, light scattering, and zeta potential measurements. Fluorescence properties of hydrophobic probe pyrene were used to find the critical aggregation concentration (CAC), critical micellar concentration (CMC), and aggregation number (Nagg) of the MC/NaDC system. Using conventional conductivity method CAC, CMC, and thermodynamic parameters of micellization i.e. standard Gibbs free energy (∆Gmic0), standard entropy (∆Smic0), and standard enthalpy (∆Hmic0), was calculated to know the information regarding the nature of micellization of MC/NaDC mixed system. The size distribution and zeta potential study give an insight into MC/NaDC interaction before and after the CAC point. The strong hydrophobic interaction between cellulose ether MC and bile salt NaDC shows that this mixed system may have further implications in lipid digestion.