Investigation of the rehydration behaviour of food powders by comparing the behaviour of twelve powders with different properties

The wettability and solubilisation ability of 12 food powders were measured and compared. Particle size and powder densities were measured and composition data was obtained to investigate the influence of these on powder rehydration. Wettability and solubilisation ability were measured over time along with an assessment of the rate limiting regime in an agitated system. The study showed that composition in particular had a major influence on wettability. The solubilisation behaviour of the powders could be classified into 3 broad categories, those that solubilised easily, those that had a significant amount of insolubles but whose soluble portion solubilised easily, and those that solubilised slowly. The slow solubilisation was most likely due to inherently strong attractions between the molecules that constituted the powder. The work highlighted that powder clumping and floating occurred with the poor wetting powders and a slimy skin formed at the powder/water interface which impeded water penetration into the bulk powder. However, the pouring of powders into the vortex in a stirred system could greatly improve wettability by improving sinkability and mechanical disruption of clumps. (C) 2016 Elsevier B.V. All rights reserved.