Physical Properties of Soybean Meal

Cereal Chem. 72(6):523-526 Physical properties of soybean meal, including particle size and 0.786 mm, respectively). Bulk density and true density were determined particle size distributions, bulk density and true density, and repose by multipycnometer and loose or zero degree bed packing, respectively. angle and drain angle, were studied in the laboratory. Evaluation of Repose angle and drain angle ranged from 30.3 to 33.20 and from 26.3 particle size and particle size distributions by a standard method reveal- to 43.70, respectively. The statistical analysis indicated that moisture ed that 70% of the particles fell into the medium and fine range (between content had significant effects both on the true and bulk densities and on 0.595 and 1.19 mm). Normal and log-normal particle size distribution the repose and drain angles. analyses showed similar results of mean diameter by mass (0.833 and Physical properties of feed ingredients are important to design, handling, storage, and drying systems, as well as the daily operation of feed plants. Unfortunately, not much information can be found in the literature about the physical properties of soybean meal. The data presented in Feed Manufacturing Technology III (Appel 1985) are not sufficient. The objectives of this study were to determine the particle size and particle size distributions, bulk density and true density, and repose angle and drain angle of soybean meal and the effect of moisture content on these properties. In soybean oil processing, the soybeans are cleaned and dehulled. They are then sent through cracking rolls, which reduce them to particles one-sixth to one-eighth the size of the beans. These fragments are graded and passed through aspirators to separate the hulls from the meats. The separated hulls are toasted and ground for animal feed. The cleaned, cracked meats pass to a conditioner-cooker that raises the temperature to =77 0 C, with a moisture content of =10%. The conditioned particles then are flaked using flaking rolls to a thickness of 0.005-0.010 in. The cell walls are broken down, and the surface area is increased for extraction. The flakes are extracted with a solvent, usually hexane, to remove the oil, forming a mixture called "micella." The oil is recovered from the micella and refined. The spent flakes are desolventized to remove the residual hexade. The desolventized flakes then are processed to produce meal of the desired specifications (Wright 1981). The bulk density of a material is the mass divided by the volume of the powder bed, which includes the volume occupied by the solid plus the volume of voids. The true density is defined as the ratio of mass to the volume occupied by that mass. Therefore, the contribution to the volume made by pores or internal voids must be disregarded when measuring the true density. The density of a material varies significantly with particle size, compaction of the material, and moisture content. Therefore, particle size and particle size distributions also must be determined. Appel (1985) reported some physical properties of feed ingredients, including the apparent densities of solvent extracted soybean meal at: 41% protein (545-577 kg/m 3 ); 44% protein (561609 kg/m 3 ); and 50% protein (657-673 kg/M 3 ). More accurate