Chemical composition, in vitro protein digestibility and in vitro available iron of blue green alga, Nostoc commune.

Blue-green alga, Nostoc commune, contained moderate amounts of protein and iron. Its in vitro protein digestibility was 43.50%. The soluble and ionic iron from the alga was extractable to some extent at pH 1.5 but was not detectable at pH 8.0. The digestion by protease did not affect the iron detection. Heat processing at 100 and 120 degrees C failed to increase the digestibility and the content of available iron. The dietary fiber in the alga may be responsible for low protein digestion and low iron availability.