Nutritive and non-nutritive attributes of washed-up seaweeds from the coast of Ceará, Brazil

This study assesses the nutritive and non-nutritive attributes of washed-up seaweeds from the Brazilian coast. It covers a broad diversity of species (24 red, nine green and four brown) with reasonable levels of proteins (10–14.8%), high ash contents (13–25%), low lipids (below 1%) and high carbohydrate contents (60%). Toxic and/or antinutritional factors were detected, such as low levels of lectins (32 and 64 HU/g of meal for chicken and rabbit trypsin-treated erythrocytes, respectively), tannins (59 mg/100 g), phytic acid (0.45%), high levels of trypsin inhibitors (99.0% inhibition) and -amylase inhibitors (70.5%). The 0/80% fraction showed moderate toxicity to mice (LD50 of 63.8 mg kg−1). The presence of heavy metals such as cadmium (0.29 mg/100 g), chromium (0.23 mg/100 g), nickel (0.26 mg/100 g) and vanadium (3.56 mg/100 g) was also detected. Despite moderate toxicity and antinutritional limitations, washed-up seaweeds represent a potential food alternative for humans after appropriate processing and environmental remediation to guarantee food safety.