Investigation of caffeine taste mechanism through a statistical physics modeling of caffeine dose-taste response curve by a biological putative caffeine adsorption process in electrophysiological response.

This work is a contribution to understand the taste mechanism of caffeine molecule using a modeling of a putative adsorption process by model expressions established by a statistical physics treatment. A physicochemical and a gustative parts are the main constituents of this work. We start with a physicochemical investigation of the adsorption process of caffeine molecule, as adsorbate in liquid phase, onto β-cyclodextrin as adsorbent. Experimental adsorption isotherm curves of caffeine onto β-cyclodextrin coated onto Quartz crystal are carried out at three different temperatures. The Hill model expression with three parameters n, N and C, established by statistical physics formalism investigated in part I, is the best fitting model of the experimental data. Thermodynamic potential functions that govern the adsorption process, such as entropy, internal energy and Gibbs free enthalpy are investigated. PSD and AED are derived by a steric and energetic derivatives of the Hill model. In part II the same method of fitting is applied to the taste electrophysiological dose-response curve by a caffeine putative adsorption on gustative nerve in caterpillar. All the physicochemical parameters introduced in the fitting Hill model expression, serve first, to analyze the taste mechanism of the bitter caffeine taste. Secondly, all these stereographic and energetic parameters will be considered henceforward for an objective characterization of caffeine molecule taste in both its two aspects, intensive and qualitative aspects of caffeine taste.