Grinding Characteristics of Black Soybeans (Glycine max) at Varied Moisture Contents: Particle Size, Energy Consumption, and Grinding Kinetics

The effects of moisture content on the grinding characteristics of black soybeans were studied. The average particle size of the black soybean powder was smaller as the moisture content was decreased by drying. Bond's constants and the work index showed lower values as the moisture content decreased. A sigmoid model accurately described the grinding kinetics of the black soybean powder (R-2 > 0.90). The parameters in the sigmoidal models were useful to explain the effect of moisture content during grinding. However, at higher moisture contents, the sigmoid model did not accurately fit the grinding kinetics. The grinding characteristics of black soybeans showed a strong dependence on moisture content. Adjusting the moisture contents of black soybeans using a pretreatment such as drying is very important to control the grinding characteristics, including the energy consumption and the average particle size, during grinding.