Enhancing Durum Wheat Grain Quality and Safety: The Role of Organic Foliar Fertilization and Selenium Biofortification in Mediterranean Farming Systems

Objectives Durum wheat quality and safety are increasingly shaped by agronomic practices that aimed to reduce reliance on synthetic inputs while enhancing nutritional and technological value. Under Mediterranean conditions, where recurrent abiotic stresses linked to climate change pose significant challenges for agricultural production and food security, novel fertilisation strategies are necessary. This study investigates the combined effects of organic foliar fertilization and selenium (Se) biofortification on gluten protein quality, grain nutrient enrichment, and mycotoxin contamination in durum wheat ( Triticum turgidum ssp. durum L.). Methods Field experiments were carried out over two growing seasons (2018 and 2019), using modern (Marco Aurelio, Nadif) and old (Cappelli, old Saragolla) cultivars. Treatments included foliar applications of organic nitrogen (N), sulphur (S), combined N + S, and Se biofortification. Analyses focused on gluten protein polymerization and assembly, grain concentrations of [N], [S], [Se], [Fe], and [Zn], and the profile of major and emerging mycotoxins. Results Organic foliar N and S application enhanced grain [S], [Fe], and [Zn] and improved gluten protein assembly and gluten index. Se biofortification effectively increased grain Se content without compromising other nutrient concentrations and significantly reduced contamination by both deoxynivalenol and emerging mycotoxins (enniatins, moniliformin). The modern cultivar Marco Aurelio combined high concentrations of micronutrients and gluten quality indices, even under water-limited conditions. Conclusion This study provides novel evidence that integrating organic foliar fertilization with Se biofortification can simultaneously improve the nutritional, technological, and safety traits of durum wheat. The findings point to agronomic strategies capable of improving grain quality and reducing mycotoxin risks in Mediterranean environments, thereby supporting more sustainable and resilient wheat production systems with direct relevance for food security.