Obtaining orange juice–maltodextrin powders without structure collapse based on the glass transition temperature and degree of polymerization

Abstract

A set of four maltodextrins (MXs) with different degree of polymerization were employed as carrying agents for the spray drying of liquid orange juice (OJ) without collapse in the microstructure; this was visually observed as fine powders non-agglomerated were obtained with a characteristic color. The powders were subjected to water adsorption and characterized. The effect of the MX added was the increase in the adsorption of water and the subsequent depression in the glass transition temperature (Tg). The microstructure did not crystalize at any water activity, but the phase changed from an amorphous solid to a solid covered by saturated liquid. Additionally, a simple mathematical model based on the molar fractions and the Tg of the individual components was proposed for predicting the overall Tg of the ternary system water–OJ–MX. The results presented herein may contribute to the processing of sugar-rich systems and in the stability of food products.

Keywords

• Maltodextrin
• orange juice
• glass transition temperature
• spray drying