Calorimetric determination of the specific heat of soybeans
Authors: Watts, K. C. And W. K. Bilanski
Description: Soybeans have the potential of being an important livestock feed. They give high yields and have a high protein content. However, inherent in raw soybeans is a chemical compound called a trypsin inhibitor (1) which causes indigestion and has other ad verse effects on simple-stomach animals. The usual commercial method of breaking down this compound uses super-heated steam in special processing plants, although a new process using L.P. gas has been patented. However, a process that could be implemented right on the farm would save livestock producers both time and money. One of these methods involves the use of a microwave oven. It is necessary to heat the beans to some specific internal temperature, dependent on the animal being fed. However, temperature determination is very difficult in a microwave field thermocouples and mercury thermometers are subject to corona discharge, alcohol thermometers burst, and waxes (although they are not affected by microwaves) first go through a plastic stage and then liquify due to the heat from the beans with which they are in contact. Other solutions included switching off the microwaves and then inserting a temperature-measuring device into the beans, or, secondly, removing a number of beans and determining their bulk temperature by a calorimetric method. The first alternative required an assumption concerning the thermal resistance between the temperature - measuring device and the beans. Due to the ellipsoidal shape of the beans, it was decided that the error due to the virtually point contact between the beans and a temperature-measuring device could not be determined to any degree of precision. Hence, this alternative was set aside in preference to the second, which assumed a knowledge of the specific heat of soybeans for the particular moisture content and temperature range.
Keywords: calorimetric determination of the specific heat of soybeans
Citation: Watts, K. C. and W. K. Bilanski 1970. CALORIMETRIC DETERMINATION OF THE SPECIFIC HEAT OF SOYBEANS. Canadian Agricultural Engineering 12(1):45-47.
Start page number: 45
End page number: 47