Characterisation of food powder flowability

This paper presents a characterisation of the flow properties of four food powders (flour, skim-milk, tea and whey-permeate). Physical property measur ements, including particle size, bulk and particle densities, water sorptio n isotherms and DSC thermograms, are presented. Powder flowability was meas ured using an annular shear cell. The flowability of the 4 food powders are compared and discussed with reference to their physical properties and the relative humidity of the surrounding atmosphere. One application of powder flowability data is in the design of hoppers. Different failure properties from shear tests are calculated for each of the food powders. They are the n applied to estimating and comparing the critical hopper dimensions for ma ss flow for each powder. (C) 1999 Elsevier Science Ltd. All rights reserved .