Characterisation of bulk and shear properties of basmati and non-basmati rice flour

Abstract

Background

The flours are often unstable in relation to their flow performance which is evident when a free flowing material ceases to flow and the processing, handling, and production parameters depend on the inherent powder characteristics and their bulk behaviour. The present study was conducted to compare the flowability of basmati and non-basmati rice flour affecting bulk handling which could be related to its particle size, shape and surface roughness (measured by Atomic Force Microscope) as well as bulk and shear properties depending upon the processing conditions. Results

Particle size (171.1-171.9 µm) of both the samples was not significantly different. However, the flowability of the non-basmati rice flour was significantly affected by its particle shape (circularity 0.487), surface roughness (124.23nm) and compressibility (25.32%) in comparison to basmati rice flour (circularity 0.653, surface roughness 113.59nm and compressibility 21.09%) making it more cohesive than basmati rice flour. Also, basic flow energy was significantly higher in non-basmati flour, thus required more energy (147.54mJ) to flow than basmati rice flour (130.15mJ). Conclusion

Overall, flowability was analysed by applying three different pressures (3, 6 and 9kPa) among which non-basmati rice flour was found less flowable (flow function coefficient, FFC 2.33 at 9kPa) in comparison to basmati (FFC 3.35 at 9kPa) creating bulk handling difficult. This study could be useful in designing processing equipments, hoppers and silos for rice flour handling.