Abstract
The water soluble fraction of nitrogen in soybean products was varied with processing for each product. In the case of Miso, approximately 60% of nitrogen were extractable, mostly as formol nitrogen.
The increase of soluble nitrogen by the action of either pepsin or trypsin was more remarkable with the soybean products less-changed by processing. The treatment by methanol or butanol of steamed soybean also increased its susceptibility for pepsin and trypsin.
Processing of soybean to increase the soluble nitrogen, such as Miso fermentation resulted in the increase of total amounts of soluble nitrogen found after subjecting those products to the action of proteolytic enzyme. This means that such processing is effective to increase the over-all availability of nitrogen.
