1. The temperature of the roasted beans should be within 220 to 245 degrees F at the discharge point.
2. When roasted, full-fat soybeans serve as a complete replacement for soybean meal as a source of supplemental amino acids, the dietary protein level should be increased 1 to 1 1/2% to maintain the same dietary calorie:amino acid ratio.
The key is the ability of the roaster to reach the ‘proper’ temperature and the length of time the bean travels through the roaster.
Research has evaluated the nutritional value (metabolizable energy ME, etc) of roasted soybean. In general, soybeans that are properly roasted, that is processed with sufficient heat to inactivate anti-nutritional factors but not destroy the protein, make good source of protein for swine.
The use of roasted soybeans versus Soybean Meal is as much an economic decision as a nutritional decision. Several research studies comparing roasted soybeans to soybean meal have indicated that properly roasted soybeans are nutritionally equal or possibly superior to soybean meal for swine. The key, of course, is ‘properly’ roasted soybeans. When soybeans are roasted, as opposed to extruded, they must be roasted at the correct temperature and the correct length of roasting time. Proper roasted soybeans should not have enough residual trypsin to result in decreased protein utilization. But, again, I emphasize the importance of ‘proper’ roasting procedures.