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.
Merki: Minerals
Tengiliður
Ólafur Reykdal
Verkefnastjóri
olafur.reykdal@matis.is
Næringargildi sjávarafurða – Meginefni, steinefni, snefilefni og fitusýrur í lokaafurðum / Nutrient value of seafoods – Proximates, minerals, trace elements and fatty acids in products
Gerðar voru mælingar á meginefnum (próteini, fitu, ösku og vatni), steinefnum (Na, K, P, Mg, Ca) og snefilefnum (Se, Fe, Cu, Zn, Hg) í helstu tegundum sjávarafurða sem voru tilbúnar á markað. Um var að ræða fiskflök, hrogn, rækju, humar og ýmsar unnar afurðir. Mælingar voru gerðar á fitusýrum, joði og þremur vítamínum í völdum sýnum. Nokkrar afurðir voru efnagreindar bæði hráar og matreiddar. Markmið verkefnisins var að bæta úr skorti á gögnum um íslenskar sjávarafurðir og gera þær aðgengilegar fyrir neytendur, framleiðendur og söluaðila íslenskra sjávarafurða. Upplýsingarnar eru aðgengilegar í íslenska gagnagrunninum um efnainnihald matvæla á vefsíðu Matís. Selen var almennt hátt í þeim sjávarafurðum sem voru rannsakaðar (33‐ 50 µg/100g) og ljóst er að sjávarafurðir geta gegnt lykilhlutverki við að fullnægja selenþörf fólks. Fitusýrusamsetning var breytileg eftir tegundum sjávarafurða og komu fram sérkenni sem hægt er að nýta sem vísbendingar um uppruna fitunnar. Meginhluti fjölómettaðra fitusýra í sjávarafurðum var langar ómega‐3 fitusýrur. Magn steinefna var mjög breytilegt í sjávarafurðum og koma fram breytingar á styrk þessara efna við vinnslu og matreiðslu. Lítið tap varð á snefilefnunum seleni, járni, kopar og sinki við matreiðslu. Mælingar voru gerðar bæði á seleni og kvikasilfri þar sem selen vinnur gegn eituráhrifum kvikasilfurs og kvikasilfur er meðal óæskilegra efna í sjávarafurðum. Kvikasilfur reyndist í öllum tilfellum vel undir hámarksgildum í reglugerð. Hrogn og hrognkelsaafurðir höfðu þá sérstöðu að innihalda mjög mikið selen en jafnframt mjög lítið kvikasilfur.
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 for 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.