Combined Biofortification of Durum Wheat with Zinc and Selenium: Effects on Semolina and Pasta Nutrient Accumulation and Yield

Agronomic biofortification of durum wheat with selenium (Se) and zinc (Zn) represents a promising strategy to combat micronutrient deficiencies in human populations relying on cereal-based diets. This study evaluated the effectiveness of soil Zn application (S0Zn: no application; S50Zn: 50 kg of ZnSO4·7H2O ha− 1) and foliar applications of Se and Zn (0 F: no application; ZnF: two applications of 4 kg ZnSO4·7H2O ha− 1; SeF: 10 g Na2SeO4 ha− 1; ZnF + SeF: combined ZnF and SeF) on nutrient accumulation and yield in durum wheat semolina and pasta under Mediterranean rainfed conditions over two growing seasons. Semolina and pasta were analyzed for nutrient concentrations, phytic acid content, and indices of Zn bioavailability, including phytic acid–Zn molar ratios and modelled fractional and total absorbed Zn (FAZ and TAZ). Foliar treatments significantly increased Zn and Se concentrations in both semolina and pasta, with the combined Zn + Se treatment reaching 36.7 mg Zn kg⁻¹ and 43.1 µg Se kg⁻¹ in semolina and 32.7 mg Zn kg⁻¹ and 41.6 µg Se kg⁻¹ in pasta. These treatments also reduced PA: Zn ratios and increased estimated Zn absorption, while improving semolina yield by up to 4%. Processing from grain to semolina and pasta resulted in moderate but consistent micronutrient losses, with retention rates ranging from 66 to 74%. Overall, combined foliar application of Zn and Se proved to be an effective strategy to improve the nutritional quality of durum wheat-derived products under Mediterranean conditions.