RECENT PROGRESS ON BIOTECHNOLOGY OF SOYBEAN PROTEINS AND SOYBEAN PROTEIN FOOD-PRODUCTS

Recently it has been recognized that the action of the enzymes contained in soybeans has negative effects on the qualities of soybean protein foods. Based upon these findings, new manufacturing techniques for high quality soybean protein foods have been developed through the control of such enzyme action. For instance, new soybean seeds lacking lipoxygenases have been developed which reduce the production of grassy-beany flavors. The gel hardness of tofu can also be controlled through the action of the lipoxygenases contained in soybeans. In addition objectionable after-tastes develop through the hydrolysis of soybean isoflavones by the beta-glucosidases which are found in soybeans. Genetic engineering of soybean proteins made a great progress in improving their functional and nutritional qualities through the modifications of genes encoding for soybean storage proteins. The application of a bioreactor for soy sauce is also described as an example of the progress on the biotechnology.