Selenium Health Benefit Values and Hg and Se speciation studies for elucidating the quality and safety of highly consumed fish species and fish-derived products

[Display omitted] •Health benefit values (HBVSe > 0) were evaluated in fish and fish-derived products.•SeMet and SeMeSeCys were identified in fish roe and ultra-processed fish products.•MeHg+ is the major Hg species present in fish-derived products.•Hg2+ percentage increases in fish lower in food chain and in fish-derived products. Nowadays, there has been an increase in the consumption of fish-derived products that constitute alternative ways of introducing fish into the diet, such as fish roe and products made from fish (crab sticks andsurimi-derived products). However, there is no data available considering selenium and mercury total contents along with speciation studies in these kinds of samples, which are mandatory for a proper safety and quality assessment. In this study,Selenium Health Benefit Values (HBVSe) in fish and fish-derived products were evaluated, resulting inpositivein all cases. Selenium speciation studies performed by HPLC-ICP-MS and confirmed by HPLC-ESI-MS/MS revealed that SeMet and SeMeSeCys are present in fish and fish-derived products. Finally, Hg speciation studiesshow that the percentage of Hg2+ increases in fishes lower in the food chain as well as in fish-derived products.