Lipoxygenases are iron-containing proteins. They contain one iron molecule in their active site. The plant-derived lipoxygenases are monomers and typically 90-110 kDa large molecules. The three-dimensional structure of soya lipoxygenase I has been solved in high resolution. Lipoxygenases also play an important role in flavour generation and off-flavour formation. They are present as endogenous enzymes in plant raw materials. Many microbes are reported to produce lipoxygenases, however, the production levels are very low and the enzyme is often intracellular. It is a great challenge to discover stable lipoxygenases and to produce the enzyme in high amount for food applications. Currently the commercial availability of lipoxygenases is limited. Enriched soya flour lipoxygenase is available and it is used for bleaching of carotenoid pigments of wheat flour and to improve baking quality.
