Seaweed is becoming a popular food source due to its high nutritional content, but may also contain potentially toxic elements (PTEs). This study investigates trends in PTEs in several species of seaweed collected in Iceland, and variations between thallus section, location, and season. As (3.8-265 mg kg-1), Cd (0.06-18 mg kg-1) and U (0.03-1.9 mg kg-1) were highest in Phaeophyta collected in February, whilst certain Chlorophyta contained the highest levels of Pb ( 0.02-1.8 mg kg-1) and Fe (25-13607 mg kg-1). Samples contained high levels of essential trace elements but elevated levels of Cd – 19 samples exceeded the maximum level (3 mg kg-1) in food supplements. As levels were also high where over half of samples exceeded the 40 mg kg-1 ML for As in seaweed-derived animal feed. Certain species grown in Iceland may be prone to high levels of Cd and not be suitable for consumption in large quantities.
Tag: Minerals
Contact
Ólafur Reykdal
Project Manager
olafur.reykdal@matis.is
Nutrient value of seafood - Proximates, minerals, trace elements and fatty acids in products
Measurements were made of the main substances (protein, fat, ash and water), minerals (Na, K, P, Mg, Ca) and trace elements (Se, Fe, Cu, Zn, Hg) in the main types of marine products prepared on the market. These included fish fillets, roe, shrimp, lobster and various processed products. Measurements were made of fatty acids, iodine and three vitamins in selected samples. Several products were chemically analyzed both raw and cooked. The aim of the project was to remedy the lack of data on Icelandic seafood and make it accessible to consumers, producers and retailers of Icelandic seafood. The information is available in the Icelandic database on the chemical content of food on Matís' website. Selenium was generally high in the marine products studied (33-50 µg / 100g) and it is clear that marine products can play a key role in satisfying people's selenium needs. The fatty acid composition varied according to the types of seafood and there were special characteristics that can be used as indicators of the origin of the fat. The majority of polyunsaturated fatty acids in seafood were long-chain omega-3 fatty acids. The amount of minerals was very variable in seafood and there are changes in the concentration of these substances in processing and cooking. There was little loss of the trace elements selenium, iron, copper and zinc during cooking. Measurements were made on both selenium and mercury as selenium counteracts the toxicity of mercury and mercury is one of the undesirable substances in marine products. In all cases, mercury proved to be well below the maximum levels in the regulation. Roe and roe products had the special feature of containing very much selenium but also very little mercury.
Proximates (protein, fat, ash and water), minerals (Na, K, P, Mg, Ca) and trace elements (Se, Fe, Cu, Zn, Hg) were analyzed in the most important Icelandic seafoods ready to be sent to market. The samples were fish fillets, roe, shrimp, lobster, and several processed seafoods. Fatty acids, iodine, and three vitamins were analyzed in selected seafoods. A few seafoods were analyzed both raw and cooked. The aim of the study was to collect information on the nutrient composition of seafood products and make this information available to consumers, producers and seafood dealers. The information is available in the Icelandic Food Composition Database. Selenium levels were generally high in the seafoods studied (33‐50 µg / 100g) and seafoods can be an important source of selenium in the diet. Fatty acid composition was variable depending on species and certain characteristics can be used to indicate the fat source. Polyunsaturated fatty acids were mainly long chain omega ‐ 3 fatty acids. The concentration of minerals was variable, depending on processing and cooking. Small losses were found for selenium, iron, copper and zinc during boiling. Both selenium and mercury were analyzed since selenium protects against mercury toxicity and data are needed for mercury. Mercury in all samples was below the maximum limit set by regulation. Roe and lumpsucker products had the special status of high selenium levels and very low mercury levels.