EXTRACTION AND CHARACTERIZATION OF FUCOIDAN FROM SIX BROWN MACROALGAE

The content and composition of fucoidan in six brown macroalgae were investigated. The influence of different washing steps and two types of extraction methods on the yield and composition of fucoidan were assessed. The composition of the extract was determined by using a colorimetric method to measure the total sugar, sulfate, and protein contents of the fucoidan. The monosaccharide composition was assessed using high-performance liquid chromatography. The structures of the algal polysaccharide were studied using Fourier transform infrared-attenuated total reflectance spectroscopy. The fucoidan content extracted using method I was 13.13% (of dry weight), 24.00%, and 22.67% from Sargassum glaucescens, Sargassum horneri, and Laminaria japonica, respectively. By contrast, the fucoidan content extracted using method II was 4.20%, 4.80%, and 4.64% from S. glaucescens, S. horneri, and L. japonica, respectively. The samples extracted using method II were lower in total sugar content but higher in sulfated content than those extracted using method I. Using method II yielded the highest fucose content in S. glaucescens (20.89%) and Hizikia fusiformis (15.89%). The proportion of H. fusiformis was lower than that of S. glaucescens because the biomass of the H. fusiformis was much larger in the wild. Therefore, we consider H. fusiformis to be a rich source of fucoidan for human consumption.