Comparison of the morpho-cytology and chemical composition of the blue-green alga, Nostoc commune Vauch. from the Philippines and Japan
2006
Briones-Nagata, M.P. | Martinez, Goss M. | Hori, K.
Nostoc commune, a filamentous, nitrogen-fixing cyanobacterium is a conspicuous component of terrestrial microbial populations from the tropics to the Antartic continent. In natural habitats, such as rice paddies, shallow streams, water ponds, and large open fields, N. commune can form spherical microscopic colonies consisting of filaments embedded in a gelatinous matrix. The application of N. commune as food, and its potential health benefits, prompted an investigation on the chemical composition and physico-chemical properties of this alga. Chemical and physico-chemical analyses of cultured spherical colonies from the Philippines (PS), discoid colonies from the Philippines (PD), and discoid colonies from Japan (JD) were conducted, and the results were compared. The protein amount varied from 23 to 29% of the dry mass. JD had higher protein content than PD and PS, and significantly higher for PS and PD. Results of amino acid analysis showed that 17 amino acids from SDS solubilized proteins of the alga. In terms of dietary fiber in the form of oxalate-oxalic acid soluble substances (OOSS), both forms of Philippine samples (PD and PS) had significantly higher OOSS content than JD. OOSS is composed mainly of polysaccharides. Glucoronic acid and galacturonic acids were identified as components of OOSS. PD contained higher crude lipid than PS and JD. The alga was also found to contain polyphenols. The tannin contents for PS, PD, and JD were 4.09, 4.94 and 4.54 mg/g dry basis, respectively. Variations in the chemical composition could be explained by variability in the environments in which the alga was grown.
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