Dough lipoxygenase

Soy beans are another crop that will not grow in Europe. The soy bean is used as a source of both protein and vegetable oil. Enzyme active soy flour has been used in bread since the 1930s. The flour contains a lipoxygenase system that assists with the development of the dough and slightly bleaches the bread. Soy flour is classed as an ingredient rather than an additive. 

The presence of lipoxygenase in plants may affect their storage and processing since it promotes the peroxidation of the polyunsaturated fatty acids (which are nutritionally essential) and can affect taste, odor, and color. Moreover lipoxygenase may influence ripening and abscission. In fact, it has been used to modify fatty acids, to bleach wheat flour, and to improve the rheological properties of wheat dough. An excellent dis-... 

Wheat lipoxygenase and soybean lipoxygenase, catalyzing oxidation of fatty acids, generate oxidized reaction products that improve the dough-forming properties and baking performance of flour. A similar role is performed by polyphenol oxidase and peroxidase. 

The lipoxygenase and dehydroascorbic acid reductase enzyme systems in dough illustrate how the rheology of proteins can be modified by either the products of enzymic reactions or the coupled oxidation of substrate and thiol groups of the proteins. 

When wholemeal flour is mixed with water, dissolved oxygen is consumed due to a lipoxygenase-catalysed peroxidation of F-puFA . The fatty acid oxidation products that are formed in low amounts in aqueous suspensions of white flour have been described previously. This paper illustrates the more substantial lipid peroxidation reactions that occur in aqueous suspensions and doughs of wholemeal flour and points out several important practical implications of this process. 

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