Effect of grinding methods on powder quality of king chilli

Abstract

The article aims to investigate the influence of cryogenic and ambient grinding on powder quality of king chilli (Capsicum chinense L.). The grinding experiments were performed using a laboratory scale ball mill. Quality of the powders was accessed by measuring the properties such as densities, Hausner ratio, compressibility index, particle size distribution, colour change, microstructural changes, and mineral compositions. Bulk density (483 kg m−3) and tapped density (556 kg m‒3) of ambient ground powder was relatively higher than that of cryo-ground powder, (bulk density 414 kg m‒3 and tapped density 480 kg m‒3). However, Hausner ratio and compressibility index of ambient ground chilli powder were significantly lower than that of cryo-ground powder. The surface morphology, shape, and size of particles of cryo-ground powder were comparatively smoother, regular and smaller in size. Moreover, the major mineral (K) content and the colour (redness, yellowness, and lightness) were found to be relatively superior for cryo-ground powder. The overall results showed cryogenic grinding provides a better and finer quality ground powder than the conventional grinding methods. The results of this study will provide the spice industries, an opportunity to select the better grinding method based on the flow and sensory quality of the powder. The powder properties may further be utilized in the process modelling and design of packaging, grinding and handling equipment.