Influence of Composition of Soluble Coffee Beverage on Glass Transition and Stickiness Phenomenon

The stability of soluble coffee beverages and the resulting uniform physical properties are of the essence in order to maintain the product quality, both during industrial manufacturing and during storage. The stickiness is one phenomenon, which is frequently encountered during the time from production to consumption of extract powders. This thesis was undertaken to investigate the relationship between the stickiness phenomenon and the chemical composition, including the water activity and the moisture content of soluble coffee beverages. The background of the investigation was to determine the influence of individual components and moisture content on the phase transition and the resulting stickiness and caking of powders in order to improve the product quality and storage stability. 13 soluble coffee beverages, including pure soluble coffees, coffee mixtures and cereal/chicory base powders, were selected for this investigation. Within the scope of the thesis, analytical methods for determination of individual components and powder stickiness were developed resp. optimized for soluble coffee beverages.