Bulk Properties

Food powders can be classified into different categories according to their handling properties. The bulk properties of food powders are a function of physical and chemical properties of the material, the geometry, size and surface characteristics of the individual particles, as well as the history of the system as a whole. This chapter introduces someways to evaluate food powder failure properties, such as angle of wall friction, effective angle of internal friction, failure function, cohesion, flowability, compressibility and other mechanical properties. These mechanical properties can be combined with environmental conditions such as moisture, temperature, particle size and chemical composition in order to condense physical and chemical issues related to the powder during manufacturing and distribution. Shear testers are used for bi-dimensional stress quantification that leads to the calculation of these properties. Other direct measurement methods for failure properties are also introduced. Handling properties such as angle of repose, angle of slide, conveying angle and angle of spatula are provided with some relevant reference methods, and new methods such as rapid methodologies are utilized for evaluating drainage, flow or conveying capabilities. Powders are classified according to handling in dispersion systems or according to their dynamic or static conditions during transport or storage.