**2. Anti-nutritional factors**

Like other plants, soybean too synthesizes a range of secondary metabolites for their adaptation and self-protection, called anti-nutritional factor (ANF). From nutritional point of view, the ANF is considered as harmful and toxic, as it interferes with normal growth, reproduction, and health. Therefore, soybean, in general, and food-grade soybeans, in particular, are expected to be free from anti-nutritional factors or allergens that may cause harm to the consumers. Soybean contains several anti-nutritional factors among which trypsin inhibitor (TI) and phytase are the most important ones. Kunitz trypsin inhibitor (KTI), which constitutes more than 80% of the total TI, is primarily responsible for improper digestibility of soybean, if consumed unprocessed. Although KTI is heat labile, yet heat inactivation process is neither fully effective nor economic. Genetic elimination of KTI is the most effective way of making soybean free from KTI [15].
