Metal Bioavailability and Risk Assessment from Edible Brown Alga Laminaria japonica, Using Biomimetic Digestion and Absorption System and Determination by ICP-MS

A new biomimetic digestion and absorption system, including in vitro bionic digestion and biomimetic membrane extraction, was used for the first time for the pretreatment of edible Laminaria japonica. After bionic digestion, 11 species of trace metals (V, Cr, Mn, Fe, Ni, Cu, Zn, Se, As, Cd, and Pb) in the resulting chyme were transformed into their final coordinated complexes and then absorbed by the biomembrane. Similar to the biomembrane between gastrointestinal tract and blood vessels, monolayer liposome was used for the first time as a biomembrane model. Affinity-monolayer liposome metals (AMLMs) were separated, determined by ICP-MS, and then used for the metal bioavailability assessment as the bioassimilated part. The action of gastrointestinal acidity and components (including digestive enzymes) was assessed on the basis of the concentration of AMLMs; the safe dosage and tolerable upper intake level of L. japonica for adults were proposed as 33.3 and 230.8 g/day, respectively.