The gluten protein composition and expression level influence dough properties and are cultivar and environment dependent. To broaden the knowledge of the durum wheat gluten proteome, three cultivars were compared in two different growing seasons by a proteomic approach. Cultivar-specific and differentially expressed spots in the two years were identified by mass spectrometry. Significant differences were observed among the cultivars: Ofanto showed the lowest protein spot volumes in the high molecular weight (HMW) and low molecular weight (LMW) <35 000 regions and the highest in the LMW 48 000−35000 region, Latino the lowest in the LMW 48 000−35 000 region, and Simeto an intermediate expression level in both LMW regions. In the warmer year the up-regulation of HMW glutenins, α-gliadins, and a globulin 3 protein and the down-expression of LMW glutenins and γ-gliadins were observed. Among the cultivars, Simeto showed the highest stability across the environments.

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.

The QUENCHERABTS (QUick, Easy, New, CHEap and Reproducible) approach for antioxidant capacity (AC) determination is based on the direct reaction of 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation with fine solid food particles. So, it may resemble the antioxidant action in foods or in human gastrointestinal trait. Here, the QUENCHER approach was used to study AC of durum wheat (Triticum durum Desf.) grains. Firstly, it was assessed which kind of antioxidants determines QUENCHER response. This has been performed by comparing AC measured by QUENCHERABTS and that measured by classical TEACABTS (Trolox equivalent antioxidant capacity) in four different extracts from whole flour of 10 durum wheat varieties containing: lipophilic, hydrophilic, insoluble-bound phenolic (IBP) and free-soluble phenolic (FSP) compounds. QUENCHERABTS data were unrelated to AC of water-extractable antioxidants and weakly correlated (r = 0.405, P < 0.05) to AC of the lipophilic ones; on the contrary, QUENCHERABTS response was mainly related to AC of IBP (r = 0.907, P < 0.001) and to a lesser extent of FSP extracts (r = 0.747, P < 0.001). Consistently, correlation was also found with the phenolic content of IBP and FSP (r = 0.760, P < 0.001 and r = 0.522, P < 0.01, respectively), thus confirming that QUENCHERABTS assay mainly assesses AC due to IBP. So, this assay was used in a first screening study to compare AC of bioactive IBP of thirty-six genotypes/landraces covering a century of cultivation in Italy. Interestingly, no relevant AC difference between modern and old genotypes was found, thus suggesting that a century of plant breeding did not decrease phenol-dependent health potential in durum wheat.

Lipophilic antioxidants are essential components of plant defense against stressful conditions. The response of carotenoids and tocols to water deficit and sulfur fertilization was investigated in durum wheat cultivars. The amounts of tocols and carotenoids were evaluated in both whole meal and semolina samples. Differences among cultivars were observed. Simeto cultivar showed a significant effect of water regime on whole meal and semolina carotenoids, with about 20% and 15% increase, respectively. Also tocols and tocotrienols of Simeto were positively affected by water stress (about 10% increase and 15% increase in whole meals and semolinas). Sulfur fertilization positively impacted mainly Ofanto whole-grain and semolina carotenoids, semolina tocols, and tocotrienols. In conclusion, water deficit occurring under a Mediterranean environment was responsible for an improvement of lipophilic antioxidant content in durum wheat; in contrast sulfur supplementation did not improve the response of the antioxidant pool under water deficit.