Selenium content and speciation differences in selenium enriched soups made from selenium biofortified plants

Food crops are major sources of selenium (Se) in many countries. In this study, we produced Se-enriched soup powders from Se-enriched vegetables, maize, wheat, and the Se-accumulator plant Prince’s Plume, respectively. In long-term stored vegetable powder, recent analyses showed that almost 80 % of total Se was inorganic Se and 20 % was organic Se compared to 53 % organic and 40 % inorganic Se 5 years ago. In maize and wheat powders, 90 % and 68 % organic Se and 3 % and 27 % inorganic Se were measured, respectively, while 90 % organic Se was measured in Prince’s Plume powder. After making soups from each respective plant powder and filtering suspended particles (residual soup solids), more than 80 % Se was present as selenite and 7 % as organic Se in vegetable broth, 64 % and 49 % as selenate and less than 20 % as organic Se in maize and wheat broths, respectively, while almost 90 % as organic Se was in Prince’s Plume broth. In the respective filtrates, we measured 50 %, 90 %, and 81 % as organic Se from vegetable, maize, and wheat soups, respectively, and < 10 % as inorganic Se from Prince’s Plume. Consumption of both broth and residual soup solids can provide plant sources of Se for increasing Se intake.