Structural characterization and bioactive and functional properties of the Brown macroalgae (Sargassum illicifolium) polysaccharide

In the present study, the water-soluble polysaccharide Sargassum illicifolium (WSPSI) was isolated by hot water, and its structural and functional properties were investigated. The extraction yield of the polysaccharide, purity, and its average molecular weight were estimated to be 16.79%, 92.22%, and 316 kDa, respectively. The examination of carbohydrate compounds by High-performance liquid chromatography (HPLC) showed that this polysaccharide mainly contains arabinose, xylose and galactose . In this study, the presence of α- and β-configurations in WSPSI was demonstrated by Nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). In this study, the oil holding capacity (OHC) and the water holding capacity (WHC) of WSPSI were estimated at 3.41 g oil/g sample and 3.97 g water/g sample, respectively. On the other hand, the study of the prebiotic activity of WSPSI showed that it can be effective in the growth and increase of the survival of the probiotic bacterium Lactobacillus casei. (ATCC 39,392). The WSPSI also showed inhibitory activity against the pathogen Salmonella typhimurium (ATCC 14,028). In addition, WSPSI had a good ability to inhibit 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (OH) free radicals. The amount of half-maximal inhibitory concentration (IC 50 ) of DPPH and OH for WSPSI were 0.43 mg/mL and 0.53 mg/mL, which were lower than that of butylated hydroxytoluene (BHT). Therefore, due to its desirable functional properties, WSPSI can be used as a novel natural component in the formulation of functional foods.