Effect of milling method on shape characteristics and flow, bulk, and shear properties of defatted soybean flours

Deffated soybean flour is an inexpensive and effective source of nutrients, however, its use in the food industry has not expanded. It is important to understand flow properties of powders for industrial applications because the flow properties present an important factor in the design of food production lines. However, currently there is no information available regarding the flow properties of defatted soybean flour. This study investigated the relationship between the milling method and the flow properties of defatted soybean flour. The flow properties were analyzed for dynamic flow, bulk (compressibility and permeability), and shear properties using a powder rheometer. The results revealed that the milling method affects particle sizes and shapes, and jet-milled defatted soybean flours presented smaller particle sizes and higher sphericity compared to hammer-milled flours. These differences in particle sizes and shapes affected the flow properties. The defatted soybean flours that were milled in the jet mill tended to be more compressible and less permeable than those milled via hammer mill. Analysis of shear properties showed no difference in the cohesion and flow properties of defatted soybeans flours within the range of 50% cumulative volume (D 50 ) of 42.0–108.1 μm. However, a significant decrease in flowability was observed with a D 50 of 9.5 μm. The flow properties analyzed were useful in designing suitable processing and storage equipment for defatted soybean flours.