Enrichment of ice cream with dietary fibre: Effects on rheological properties, ice crystallisation and glass transition phenomena

In the present study, the effects of four dietary fibre sources (oat, wheat, apple and inulin) on the rheological and thermal properties of model sucrose-polysaccharides solutions and ice cream mixes were investigated. The content of fibre in insoluble compounds increased significantly the viscosity and the shear thinning behaviour of the model solutions and ice creams, due to the increase of total solids and the formation of networks comprised of hydrated cellulose and hemicellulose. The increase of soluble material did not alter significantly the rheology of the samples but limited the freezing point depression and elevated the glass transition temperatures, indicating a potential cryoprotective action. The use of oat and wheat fibre favoured viscosity development due to water-binding, whereas inulin caused a remarkable increase of glass transition temperature (T-g) in model solutions and ice cream mixes, indicating the reduction of water molecule mobility from the bulk aqueous phase to the ice crystals' surface. Apple fibre addition greatly increased viscosity and elevated the T-g values, particularly in the presence of proteins. Thus, our results suggest the potential use of dietary fibres as crystallisation and recrystallisation phenomena controllers in frozen dairy products. (C) 2008 Elsevier Ltd. All rights reserved.