Because humans and animals can't eat raw, toxic soybeans, the beans have to be roasted first. This involves heating the soybeans to release the trypsin inhibitors.

It is very important that the beans don't get too hot during the roasting process, otherwise the proteins they contain will be destroyed. If the beans are roasted too cold, the trypsin inhibitors can't be destroyed and the beans remain inedible. This is why soybeans should always be heated between 100°C and 130°C, because the quality of the feed always depends on the processing.