Effect of Heat Treatment on the Biological Value of Soybeans

IT HAS been well established that the nutritional value of soybeans is improved by heat treatment. The literature fails to clarify just how much heat is desirable to produce the greatest biological value. Much of the earlier work was done with the heat treatment incidental to efficient extraction of the oil. The conditions reported to bring out maximum biological value vary widely. Such effect is credited to heating to 140–150°C. for 2 minutes in the expeller process, to 105°C. for 90 minutes in the cooker in the hydraulic process, and to 98°C. for 15 minutes in the solvent extraction process (Wilgus, Norris, and Heuser, 1936). Obviously not all of these conditions can be considered ideal. A number of theories have been advanced to explain the value of heat treatment. The one perhaps most widely believed is that the sulfur-containing amino acids are locked up in the raw soybean in . . .