Bulk and flow characteristics of pulse flours: A comparative study of yellow pea, lentil, and chickpea flours of varying particle sizes

The demand for pulses is increasing due to their numerous nutritional, sustainability, and agronomical advantages. However, studies on the bulk and dynamic flow properties of pulse flours, which are crucial for adequate handling and processing, are scarce. This study was performed to investigate the flow properties of yellow pea, lentil, and chickpea flours and compare them with wheat flour. Pulse flours of different particle sizes were produced using a laboratory roller mill through adjusting the settings of the roll gap opening and sieve arrangement and employing 75, 150, and 200 μm bottom sieves for small, medium, and large-sized flours, respectively. The flour flow properties were analyzed using a Hosokawa powder tester and FT4 powder rheometer. Chickpea flours had the lowest bulk density and the highest aeration ratio and were more compressible and cohesive among all the pulse flours and wheat flour. The small-sized flour for each pulse grain was more cohesive than the large-sized flours. For nearly all tests, chickpea and small-sized yellow pea flours were characterized as non-flowing powders, while medium and large-sized lentil flours showed relatively good flow properties comparable to wheat flour. Overall, pulse flours had lower bulk density and were classified as poor flowing flours compared to wheat flour. The production of small-sized pulse flours is not recommended because of their low bulk density, high compressibility, and poor flow properties. Adjustments to equipment will be necessary for the incorporation of pulse flours into modern industrial platforms. This study will aid the milling and baking industries in preparing for pulse grain processing and benefit transportation companies in evaluating pulse flours for proper handling.