Physicochemical properties in relation to the flow behavior of soybean meal

Abstract Caking of soybean meal during storage and the resultant difficulty in discharging from storage bin is a practical problem in animal feed‐related industries. This study investigated the physicochemical factors related to soybean meal flowability and the effect of anticaking agents. Results showed the soybean meal had a D 50 of 389.1 µm and a D 90 of 1.098 µm. The equilibrium relative humidity of soybean meal at various ambient temperatures ranged from 57 % to 69 %. Moisture had a major influence on soybean meal flowability and the critical moisture content for loss of free flow capacity was around 17.81 % (wet basis, wb). Soybean meal was characterized as amorphous by X‐ray diffraction analysis, and its glass transition temperature is greatly affected by the moisture content. The addition of silicon dioxide helps keep soybean meal free flowing when stored at a relative humidity of 90 % and a temperature of 45 °C possibly due to its low affinity for moisture. Overall, moisture absorption is perceived as the main factor causing the occurrence of caking of soybean meal.