Moisture sorption in mixtures of biopolymer, disaccharides and water

The moisture sorption of ternary mixtures of biopolymer, sugar and water is investigated by means of the Free-Volume-Flory-Huggins (FVFH) theory. The earlier FVFH theory developed for binary mixtures of biopolymer/water and sugar/water has to be modified to account for two effects: 1) the change in the glass temperature due to the non-ideal mixing of biopolymer and 2) inhibition of self-association of the polymer if the mixture is quenched very fast into the glassy state. The modified FVFH theory forms a good basis for predicting moisture sorption for quaternary mixtures of biopolymers, di-, mono-saccharides and water – which can be viewed as a model for vegetables and fruits.