Soybean Protease Inhibitors in Foods

The major types of soybean protease inhibitors are the Kunitz inhibitor (KSTI) and the Bowman‐Birk inhibitor (BBI). Enzymatic analysis and rocket Immunoelectrophoresis were used to specifically quantitate the amounts of KSTI and BBI in various soy foods. Many soy products such as soy flours, soy concentrates and soy isolates contained significant amounts of KSTI and BBI. Some soy foods contained small but still detectable levels of KSTI and BBI.