Lipoxygenase wheat

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. 

Blendford, D. 1995. Colouring consumers perceptions. Food Ingredients Analysis Int. 17, 10-11. Borrelli, G.M., Troccoli, A., Di Fonzo, N., and Fares, C. 1999. Durum wheat lipoxygenase activity and other parameters that affect pasta color. Cereal Chem. 76, 335-340. 

Walsh, D.E., Youngs, V.L., GiUes, K.A. Inhibition of durum wheat lipoxygenase with L-ascorbic acid. Cereal Chem. 47, 119 (1970)... 

Germ tubes of Puccinia graminis tritici wheat plants (not in culture) lipoxygenase (45)... 

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-... 

The importslnce of lipoxygenase increases when soybean flour is added to wheat flour to improve baking quality or when soybean flour is admixed in larger quantities to improve the protein nutritional quality. 

Phenidone (l-phenyl-3-pyrazolidone) inhibited total volatile oil yield in wheat by 43%, which was the largest decrease we found (Table V). Nordihydroguaiaretic acid, an aromatic polyphenol caused a 32% inhibition in total volatile oil yield. Acetylsalicylic acid, on the other hand, did not affect yields. Acetylsallcylic acid is a strong inhibitor of cyclooxygenase but a weak inhibitor of lipoxygenase (28). On the basis of these... 

The unsaturated Cg aldehydes and alcohols probably arise in wheat from cleavage of the 9—10 double bond of unsaturated C g fatty acids, linoleic and linolenic acids (Figure 2). Galliard and coworkers (12,13) have partially purified enzyme systems capable of catalyzing these transformations. Lipoxygenase initially converts linoleic and linolenic acids to 9-hydroperoxides which are subsequently cleaved by hydroperoxide lyase to volatile Cg unsaturated aldehydes and 9-oxo-nonanoic acid. The 3-enals are the primary volatile cleavage products from the fatty acids and these are transformed by an isomerase to the more stable 2—enals (14). The 3—enals are rather unstable but Hatanaka et al. (15) have confirmed their presence in plant tissue with authentic samples. The Cg... 

Lipoxygenases will also catalyse co-oxidation reactions. This is used both in assay methods for the enzyme and in commercial applications. An example of the latter is the addition of soybean or broad bean flours (both rich in lipoxygenase activity) to wheat flour in order to bleach pigments for white bread production. Enzymes from different sources differ in their co-oxidation ability, e.g. soybean type-I enzyme has poor activity in this regard while soybean type-II enzyme has high co-oxidation activity. The reaction probably proceeds by a free-radical process (Veldink et al., 1977) and requires the presence of a substrate (e.g. linoleic acid) as well as the co-substrate. The extent of the cooxidation may depend on the lifetime of the radical intermediates and the relative efficiency of the lipoxygenase-mediated radical reduction (Weber and Grosch, 1976). 

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