Nutrient quality of leaf protein concentrates produced from water fern (Azolla africana Desv) and duckweed (Spirodela polyrrhiza L. Schleiden)

The nutritional and some antinutritional components of leaf protein obtained from water fern (A. africana) and duckweed (S. polyrrhiza) were determined. Samples were harvested, minced and the leaf protein concentrates coagulated at 80°C in a water bath and then centrifuged. The leaf protein concentrates (LPC) and the residual pulp fibres were milled and analysed for proximate and antinutritional constituents. Crude protein content of LPC from water fern was 71.3% and 64.4% for duckweed. The residual pulp fibres contained 12.6% and 19.9% crude protein for water fern and duckweed, respectively. The LPC from the two weeds were low in lipid and fibre contents. Cyanide contents for LPC from water fern and duckweed ranged from 0.12 mg/100 g to 0.15 mg/100 g. Generally, contents of phytin and tannin and other extractives of the two aquatic plants were lower (P < 0.05) than in the original weeds.