Health–beneficial compounds from edible and waste bulb components of sweet onion genotypes organically grown in northern Europe

The onion sweet bulb genotypes grown in the Crimean republic (Russia) have a high nutritional value, but are still poorly characterized so far. Research was carried out in order to assess quality, antioxidant and mineral composition features of 9 Crimean genotypes in comparison with the Italian sweet variety ‘Tropea’. ‘Yaltinsky 6А’ showed the highest yield. Beam Promine attained the highest values of bulb dry residue, soluble solids and total sugars, but the lowest monosaccharides content. The Crimean genotypes showed higher levels of ascorbic acid and total acidity than ‘Tropea’, but lower concentrations of Fe, Cu, Mn and Zn. The Crimean genotypes examined showed interesting yield and quality performances, and also the potentiality to valorizing the bulb peel for extracting health–beneficial compounds such as antioxidants.