Examination of nitrate-nitrite (no3-no2) accumulation of beetroot and sweet potato, in regard to the development of the methemoglobinaemia syndrome

Although strictly controlled, vegetables complement the multifarious diet of babies, and it often happens that babies younger than 8-10 months are taken to hospital in critical condition due to nitrate poisoning. The disease is called methemoglobinaemia. Mothers usually feed their babies homemade carrot puree and thus they provide the necessary carotene and vitamin A for them. In the babies’ stomachs the nitrate (NO3-) will be released and, due to the absence of a defence mechanism, it is transformed to nitrite (NO2). The nitrite oxidizes the oxygen-carrying hemoglobin (Hb) and it becomes methemoglobin (MetHb). The MetHb is unsuitable for transporting oxygen, therefore, if 30-40% Hb is transformed into MetHb, hypoxia occurs and, if at least 70-80% of Hb is transformed into MetHb, then blue discoloration of mucous and respiratory failure occur. Beetroot and carrot are susceptible to nitrate accumulation root vegetables. During its storage the amount of nitrate increases. However, it is widely used for fresh consumption and as a raw material for baby food. The sweet potato (Ipomoeabatatas(L.) LAM) we examined, grown with different technologies on sandysoil, did not accumulate nitrate above the permitted concentration of baby puree of limit of 200 mg/kg. On the basis of our observation sweet potato is not susceptible to nitrate accumulation, therefore it might replace carrotas raw material for baby food and homemade carotenoid-richpuree in the future. Its growing is absolutely safe and profitable on sandy soil and other loose soil on small plots in the region of the South Plains of the Carpathian Basin. Production of sweet potato, a member of the Convolvulaceae, production can be fitted into the plant rotation dueit phylogenetic dissimilarity to conventionally grown crops, therefore it can greatly enhance the sustainable horticulture in Hungary.