Soymilk is a popular beverage in many countries, especially in Asian countries (Ono, 2008). It is rich in proteins, iron, unsaturated fatty acids, and niacin, but low in fat, carbohydrates, and calcium (Zhao et al., 2018). The soymilk benefits people who are lactose-intolerant or live in the regions where the supply of animal milk is inadequate. In addition, soymilk also contains some functional components such as Kunitz trypsin inhibitor (KTI), Bowman-Birk inhibitor (BBI), phytic acid, and tannins. Kunitz and Bowman-Birk are the most studied inhibitor families and are found in abundance in various leguminous plants (Oliveira et al., 2012).