Distribution along durum wheat kernel of the components involved in semolina colour

A bright yellow colour of pasta is an important qualitative trait for the durum wheat industry. Final colour is the result of the balance between yellow and brown components in semolina. Carotenoid pigments and lipoxygenase (LOX) enzyme are mainly involved in yellowness, whereas peroxidase (POD) and ash affect brown hue. All these components have a different distribution across the kernel, with varietal differences too. This study aimed to evaluate the distribution pattern of carotenoid pigments, α-tocopherol, linoleic acid, and ash content as well as of LOX and POD activities within the kernel of six durum wheat cultivars characterised by different pigment content and hydroperoxidation activity of LOX in semolina. The results confirmed differences in the distribution of these components across the kernel and among varieties. Additionally, this study identified for some components (POD, pigments and bleaching activity of LOX) a higher effect of genotype whereas for others (ash, α-tocopherol, hydroperoxidation activity) a marked effect of the debranning process. These results suggest that improvement of the final semolina colour could be reached both through breeding activity, enabling an early selection of better lines, and through an appropriate debranning process.