Analysis of speciation and bioavailability in vitro of major selenium species in selenium-enriched Rice and pork

Selenium plays a crucial role in preventing chronic diseases. In China, pork and rice are primary dietary sources of selenium; however, there is limited knowledge regarding the speciation and bioavailability of selenium in these foods. This study investigated the effects of key parameters on the selenium extraction efficiency from selenium-enriched rice and pork. Additionally, the in vitro bioaccessibility and bioavailability of selenium were evaluated. Results indicated that the total selenium extraction efficiency from rice was 83.85 %, from pork was 90.08 % under the optimized conditions. In rice, selenium was predominantly found as selenite (Se (IV)) (32.95 %) and selenomethionine (SeMet) (50.98 %). In pork, SeMet constituted 88.81 % of the total selenium content. The bioavailability of SeMet was 18.56 % in pork and 24.32 % in rice, compared to just 8.46 % for Se (IV) in rice. The insights gained will serve as a reference for optimizing selenium extraction processes and guiding dietary supplementation strategies.