Cast-tape drying of tomato juice for the production of powdered tomato

Cast-tape drying (CTD) is a process for producing dehydrated food powder. It consists of spreading a viscous fluid over a support whose lower surface is heated by water or steam. The aim of this study was to evaluate the kinetics of CTD for producing powder from tomato juice with and without maltodextrin, and to compare the physicochemical properties of this powder with those observed in powders produced by freeze-drying and spray drying. CTD time for the tomato juice-maltodextrin mix was longer (12 min) than the observed for pure tomato juice (8 min) to reach 0.03 g g(-1) (dry basis). Adding maltodextrin to the juice increased the glass transition temperature and facilitated removing the dried flakes from the support. Powders with maltodextrin showed solubility higher than 95%. The dispersion time of powders containing maltodextrin obtained by spray-drying was higher (632 s) than the same parameter for powders from the other processes (less than 30 s). Powders from spray-dryer had lighter color than those from CTD, a spherical structure and tendency to agglomerate. Therefore, CTD of tomato juice with maltodextrin is a viable and technologically competitive alternative for producing tomato powders. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.