Effects of milling-process and pasta making on ABTS●+ scavenging activity of hydrophilic and lipophilic extracts of durum wheat varieties

Epidemiological studies associated consumption of whole-durum wheat products with reduced incidence of chronic diseases, diabetes and cancer. These health benefits have been mainly attributed to antioxidant activity (AA) due to the unique phytochemical content of wheat. Milling, extrusion and drying process can influence the activity of these beneficial compounds. In order to have a deep insight into the changes of nutritional value from raw material to pasta, the aim of this study was: i) to compare the AA of hydrophilic and lipophilic extracts of five durum wheat genotypes along the pasta chain; ii) to evaluate the changes in antioxidant properties of whole meal after processing in semolina and pasta. To this aim TEAC (Trolox Equivalent Antioxidant Capacity) assay based on ABTS•+ [2,2’-azinobis(3-ethylbenzothiazoline- 6-sulfonic acid) scavenging activity was used due to its high reproducibility and simplicity. Low genotype variability was observed for both hydrophilic and lipophilic extracts. Milling process caused a significant decrease in AA due to the removal of the outside layers of the kernel. This decrease was more marked for lipophilic extracts due to the different distribution of hydrophilic and lipophilic antioxidants along the kernel. Pasta making process while determining a further decrease in AA of lipophilic extracts caused a slight increase in AA of hydrophilic extracts compared to semolina. This might be due to melanoidins formed during Maillard reaction. Only for lipophilic extracts a predictive evaluation of semolina and pasta ABTS•+ scavenging activity was possible by testing raw material.