Determination of Selenoneine in Seafood and Seafood-Derived Products.

Background: Selenoneine exhibits antioxidant properties and is thus expected to become a new functional ingredient. Accurately determining selenoneine levels in foods is therefore critical.

Objective: This study investigated and validated extraction methods for selenoneine in seafood and seafood-derived products.

Method: Selenoneine was extracted from seafood and seafood-derived products by sonication for 1 h and incubation at 37 °C for 24 h in a solution of 50 mmol/L dithiothreitol (DTT). The concentration of selenoneine was then determined using liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) and size exclusion column chromatography using a mobile phase of 0.1 mmol/L ammonium acetate with 0.1% IGEPAL®.

Results: The method was validated using a dithiothreitol (DTT) solution that effectively extracts selenoneine. The limit of detection (0.020-0.030 mg/kg), limit of quantitation (0.067-0.099 mg/kg), repeatability (3.4-8.9%), intermediate precision (4.1-8.9%), and trueness (recovery of 94-109% based on spiked samples) of the proposed method were satisfactory for determining selenoneine in seafood and seafood-derived products. Selenoneine was detected in migratory fish and processed migratory fish products obtained in Japan. Particularly large amounts of selenoneine were detected in dark muscle of bluefin tuna.

Conclusions: Using a reagent reactive to thiol groups, selenoneine was effectively extracted from seafood and seafood-derived products. The results of method validation analyses were satisfactory. Selenoneine was detected in processed products prepared from migratory fish, indicating that selenoneine remains even after processing. Water-soluble selenoneine was found to be extracted in the liquid.

Highlights: Selenoneine could be effectively extracted using DTT, and determination of selenoneine in various seafood was possible using LC-ICP-MS.