Soybean Oilseed Presses

Introduction to Soybean Production

Soybeans are an oilseed commodity that have a diversity of processing and marketing opportunities for the producer, largely attributed to the substantial protein and oil content of the seed (Clemente & Cahoon, 2009). After harvest, the crop is often put through an extrusion process, whereby oil is extracted from the seed, leaving a high-protein oilseed cake that can be further processed into a livestock feedstuff known as soybean meal. Studies conducted by Ahrar & Schingoethe (1979) and Pongmaneerat & Watanabe (1992) have shown the importance of including soybean meal as a supplement in livestock feed rations, especially in regions of the world where protein intake is limiting. Similarly, Lardy (2008) showed the benefits of integrating soybean meal into livestock diets when grazing marginal rangelands or feeding low quality forages.

 

Historically it has been difficult to press soybeans at smaller scales due to the significant capital required to purchase automated equipment, or the significant labour needed to extract the oil by traditional methods; however, modern small-scale oilseed presses allow individual producers to mechanically extract soybean oil at lower levels of production (Energrow, 2015). Producers that harbour this technology benefit by being able to produce their own vegetable oil and soybean meal on-farm, with less capital investment than is needed for large commercial oilseed presses.

 

Soybean Oil Extraction

There are several different approaches that can be used for the extraction of oil from soybean seeds. Each method varies in terms of the amount of oil that can be successfully recovered from the seed, and the amount of equipment required to do so. In a detailed evaluation by Axtell and Fairman (1992), it is shown that the extraction process can be completed through traditional methods, as well as using both manual and power oilseed presses. These methods are outlined in table 1, including an overview of each system.

 

Table 1: Most common extraction procedures for oilseed commodities worldwide

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The details on the various oilseed presses presented in table 1 come from literature by Axtell and Fairman (1992) and Head et al. (1995).

 

As shown in table 1, the traditional and manual methods offer the benefits of less sophistication, at the expense of higher labour inputs. At the other end of the spectrum, the power oilseed press allows for continuous flow of material, and greater oil recovery rates; however, a large capital investment must first be undertaken to acquire the necessary mechanization. When considering which type of press could be beneficial in developing nations, the factors of cost and required labour need to be balanced in order to make the export feasible. Figure 1 below shows a typical animal powered ghani to better illustrate the setup for traditional oilseed presses. This method can be beneficial in terms of its minimal capital requirements and lack of power required. Figure 2 depicts a manual plate press, illustrating the perforations in the cylinder that allow the oil to be released. The figure helps to visualize the batch system which could make this style of press very slow and tedious for the operator.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 1: Depiction of a traditional animal powered ghani used for oilseed extraction (Axtell & Fairman, 1992)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2: Depiction of a manual plate press used for oilseed extraction (Axtell & Fairman, 1992)