Transfer of Water and Volatiles at Interfaces: Application to Complex Food Systems

Abstract

During processing, storage and consumption, mass transfer of various small molecules (water, gases, flavour compounds or other solutes) occurs between the different phases in complex food products, or between complex food and its surroundings. These mass transfers can lead to physical or chemical changes and thus induce food quality modifications. The objective of this paper is to better understand the behaviour of small molecules at the interfaces, especially in model heterogeneous food systems. Different techniques have been designed to characterize mass transfers of these small molecules and their effects on food properties. In particular, techniques such as rotative diffusion cell or Fourier transform infra-red spectroscopic analyses with modelling have been established. Some examples of results are presented to demonstrate the influence of the physicochemical parameters on mass transfers: thermodynamic parameters such as partition coefficient, sorption or solubility coefficients, hydrophobicity, or kinetic parameters like diffusion and permeation coefficients. Not only the composition of the matrix, but the structure and the process also influence mass transfer. Observed results can be explained by similar phenomena, even if applications seem very different.