Physicochemical and structural characterisation of marine algae Kappaphycus alvarezii and the ability of its dietary fibres to bind mutagenic amines

The physicochemical and structural characteristics of the bioactive components of the marine algae, Kappaphycus alvarezii, were determined, and the ability of its dietary fibres to bind mutagens is reported. Swelling capacity (15.0 mL g(-1)) and water retention capacity (10.4 g g(-1)) were observed to be high and were influenced by dietary fibre fraction. Presence of sulphur is a unique characteristic of the marine dietary fibre. Insoluble fraction contained galactose (29.9 %) and glucose (21.1 %), and high Klason lignin (10.6 g (100 g)(-1)); whereas, galactose formed the single monomeric unit in the soluble fractions. Binding of mutagenic amines, benzo alpha pyrene (B alpha P) and 3-amino-1-methyl-pyrido(4,3-b)indole (Trp-P-2) to insoluble fraction were comparatively high, while soluble fraction showed greater binding to B alpha P and 2-amino-9H-pyrido(2,3-b)indole (A alpha C). The hydrophilic-lipophilic partition coefficient (Log P) and the polar surface area of the amines were positively and negatively correlated to the dietary fibre components, respectively. Klason lignin content significantly affected the binding capacity. A statistically significant multi-linear model was developed relating these properties to the binding capacity. Chemical analysis also indicated high amounts of amino acids, tyrosine and arginine (2.6 and 1.5 g (100 g)(-1), respectively), and polyunsaturated fatty acids, eicosapentaenoic and docosahexaenoic acid (13.6 %). The current study indicates the uniqueness of the marine algae as valuable food and dietary supplement.