Determination of physicochemical properties of sulphated fucans from sporophyll of Undaria pinnatifida using light scattering technique

The weight average molecular weight (Mw) of the intact sulphated fucans extracted with water from the sporophyll of Undaria pinnatifida without acid treatment was determined using the high performance size exclusion chromatography coupled to multiangle laser light scattering and refractive index detection (HPSEC-MALLS-RI) system. The effects of different heating conditions on the determination of Mw were investigated. The extracted intact fucoidans mostly consisted of carbohydrates (54.9%) and sulphate (41.5%) with monosaccharide composition of 78.8% fucose and 21.2% galactose. The Mw of the intact fucoidans was reduced from 23,600 to 5200 kDa when heated in boiling water for 1–15 min. Microwave heating for 30 s decreased the Mw of fucoidans to 2400 kDa despite no significant polymer degradation. The results indicate that the 30 s-microwave heating yielded a more accurate Mw value of the intact fucoidans than any other heat treatments used in this study.