Exploring Nutritional Quality and Bioactive Compounds in Oat Mediterranean Landraces and Cultivars

Oat (<i>Avena sativa</i> L.) is increasingly recognized as a functional food due to its unique profile of antioxidant and health-promoting compounds. Beyond its traditional role, our study reveals that Mediterranean landraces and related species harbour exceptional variability in both their nutritional and bioactive traits, offering untapped potential for functional food development. We analysed 126 genotypes, including landraces and cultivars, from 18 Mediterranean and European countries, quantifying the β-glucans, arabinoxylans, phenolic acids (soluble and cell wall bound), avenanthramides (AVAs: A, B, and C), carbon (C), nitrogen (N), C:N ratio, and protein content. The protein levels ranged from 9.5% to 18.5%, with several genotypes exceeding 17%, far above typical oat averages. The β-glucans reached clinically relevant thresholds (>5%) in multiple accessions, while the arabinoxylans surpassed 2% in selected genotypes. The phenolic acids and avenanthramides showed striking diversity, with some landraces accumulating more than 2000 µg/g of total AVAs. The species and phenology strongly influenced the grain composition. Thus, A. strigosa exhibited the highest β-glucan and avenanthramide contents, while early-heading genotypes had doubled avenanthramide levels compared to late-heading ones. A correlation analysis revealed synergistic patterns among the β-glucans, avenanthramides, and proteins, suggesting multi-component interactions that could enhance antioxidant functionality. These findings underscore the strategic value of Mediterranean oat germplasm for breeding programs targeting high-protein, fibre-rich, and antioxidant-enhanced cultivars. By exploiting this diversity, oats could play a pivotal role in preventing chronic diseases and advancing sustainable, health-oriented food systems.