Proteinase legumes

Some legumes, including raw soy or peanut flour are known to contain certain antinutritional factors such as proteinase inhibitors and hemagglutinins or lectins (21,22). These factors can be inactivated, for the most part, by moist heat, during processing. Interestingly, peanut flour contained more trypsin inhibitor and lectin than did soy flour (22). 

A number of proteinase inhibitors, often called trypsin inhibitors, are known to occur in seeds of legumes (Ryan, 1981 Weder, 1981). These polypeptides often inhibit both trypsin and chymotrypsin and block digestion of many legume seeds. Cooking deactivates most of these compounds. 

Irreversible inhibition can also occur in the presence of halogenated methyl ketones which alkylate the active histidine residue (cf. 2.4.1.1), or as a result of the action of proteinase inhibitors, which are also proteins, by interaction with the enzyme to form inactive complexes. These natural inhibitors are found in the organs of animals and plants (pancreas, colostrum, egg white, potato tuber and seeds of many legumes cf. 16.2.3). The specificity of serine... 

Antinutritive substances, e. g., allergenic proteins, proteinase inhibitors, lectins and cyanogenic glycosides, are found in food raw materials. These substances will be described in this chapter since a large variety have been identified in legumes. 

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