Electrochemical coagulation of soybean protein; tofu (soybean curd) production by an electro-reaction

Abstract

Effect of direct current on soymilk coagulation was studied to establish a new processing method for food. Soymilk was treated with direct electric current (60 mA) in an anode chamber. The treated soymilk gave tofu-like gel only by simple heating. The obtained tofu-like gel showed appearance and texture similar to a commercial kinu-tofu. Sodium dodecyl sulfate gel electrophoresis showed that the electric treatment did not change the state of covalent cross linkage including disulfide bridges among the soybean protein molecules. Therefore, non-covalent intermolecular interactions may play an important role in the gel network formation. Though the oxidation of the soymilk in the anode chamber cannot be ruled out, the treated soymilk caused almost no change on peroxide value of the oil component, the active chloride content or the oxidationreduction potential. Nor was any mutagenicity observed for the treated soymilk. Therefore, the electric treatment with direct current is considered a safe technique for food processing.