Effects of modified processing conditions on oxidative properties of semolina dough and pasta

During pasta making, semolina is subject to various modifications that are mainly related to oxidative activities with relative effects on some of its components. To evaluate the involvement of hydroperoxidation and bleaching of lipoxygenase (LOX) and peroxidase (POD) activities on loss of pigments and -SH groups, their behavior in semolina and during processing was analyzed. Processing was done in standard and four experimental conditions, applying chemical (pH 5.0 and 8.0) and physical (10 and 40degreesC) treatments, during the mixing and extrusion phases, to study their effects on components. Results pointed out that treatments principally affected hydroperoxidation and bleaching activities of LOX rather than the POD. During pasta making, enzymatic activities showed the same trend in all cultivars, and this was reproducible in all the experimental conditions. Temperature effects on preservation of components were modest, whereas pH 8.0 improved the residual pigment and -SH group content in pasta, probably because of the concomitant reduction of oxidative enzyme levels. Finally, out of the four investigated wheat cultivars, Cosmodur showed the best performance in the experimental conditions applied. In fact, high pigment content and yellow index associated with low oxidative activity levels in semolina and in processing samples resulted in better pasta color. Such findings have confirmed that breeding and technological approaches may play an important role in the control of oxidative activities during pasta making, preserving the constituents that positively influence the final pasta color.