Biofortifying Scottish potatoes with zinc

Abstract

Background and aims: The diets of many people lack sufficient zinc (Zn). This article investigates the production of potato (Solanum tuberosum L.) crops with greater tuber Zn concentrations to increase dietary Zn intakes. Methods: Field experiments were undertaken to increase Zn concentrations in potato tubers using foliar Zn fertilisers. Results: Foliar Zn fertilisers increased tuber Zn concentrations but excessive applications reduced tuber yield in all four potato genotypes studied. Zinc oxide and zinc sulphate were more effective than zinc nitrate as foliar fertilisers for increasing tuber Zn concentrations whilst maintaining yields. Foliar Zn-fertilisers increased Zn concentrations in both flesh and skin of tubers. Although Zn-biofortification had no effect on the concentrations of iron, manganese, copper, calcium, magnesium or potassium in tubers, it increased tuber phytate concentrations. Cooking reduced Zn concentrations in Zn-biofortified tubers and this effect was exacerbated by peeling. After cooking, the quotient of Zn concentrations in Zn-biofortified/non-biofortified tubers ranged from 2.36 to 3.58. Applying foliar Zn fertilisers to a preceding potato crop increased Zn concentrations in grain of a following barley crop significantly in only one out of 3 years. Conclusion: Foliar Zn fertilisers can increase Zn concentrations in potato tubers and, potentially, dietary Zn intakes.