Sugar alcohols – Multifunctional agents in the freeze casting process of foods

• Production of fast dissolving tablets of food by a freeze casting process using binder is proposed.
• Sugar alcohols improved the tensile strength and the dispersal/dissolving rate of tablets.
• Sugar alcohols strongly depressed the freezing points of aqueous suspensions.
• The change in thermodynamic properties of suspensions explained the morphologies of pores.
• Isomalt shows a better result than sugar did.

The successful production of a new convenient dosage form, namely, a fast and easily dissolving/dispersal tablet was presented in a previous study (Nguyen and Ulrich, 2014). The highlight and interesting point of that work is the introduction of sugar as a binder which dramatically improved both the tensile strength and dispersal behavior of produced tablets. In this work, the investigation on the effect of sugar alcohols (i.e., isomalt and xylitol) was carried out in order to find the mechanism on how the binders (sugar alcohols) change the properties of the tablets. The effects of sugar, isomalt and xylitol on the key properties of the tablets (i.e., the tensile strength, the dispersal/dissolution behavior), the morphology of pores and tablets, especial the thermodynamic properties of aqueous suspensions were investigated. It was found that sugar alcohols depress the freezing points of aqueous suspensions, reduce the ice growth rate and induce to form a new pore morphology, a sphere-like porous solid body. Isomalt as binder improves the properties of the produced tablets to a higher degree than sugar and xylitol. A fast dispersal cocoa tablet (16 mm ∅, 10 mm height) with a fast dispersal time of lower than 1 min and a better crushing force of 45 N (i.e. 0.18 N/mm2 diametral tensile strength) was obtained.