Physicochemical properties and surface activity characterization of water-soluble polysaccharide isolated from Balangu seed (Lallemantia royleana) gum

The aim of this research was to investigate physicochemical properties and surface activity characterization of Balangu seed polysaccharide and its fractions. Balangu seed (Lallemantia royleana) gum was fractionated according to its fractions molecular weight difference by ethanol. Its fractions were named PER-Balangu (high molecular weight) and SUPER-Balangu (low molecular weight). The results showed the molecular weight value of Balangu, PER-Balangu and SUPER-Balangu were 3120 kDa, 6130 kDa and 2050 kDa, respectively. Moreover, the highest and lowest protein content related to SUPER-Balangu (10.8%) and PER-Balangu (6.03%), respectively. The uronic acid value of Balangu, PER-Balangu and SUPER-Balangu were 15.16%, 9.75% and 20.35%, respectively. The FT-IR spectra showed the principal functional groups included of (OH), (C–H), (−COO−) and (C–O–C). The intrinsic viscosity value of Balangu, PER-Balangu and SUPER-Balangu were 45.11 dL/g, 29.4 dL/g and 36.51 dL/g, respectively. SUPER-Balangu improved the surface activity properties, which was significantly reduced by increasing SUPER-Balangu concentration (p < 0.05). According to the result of this study, protein content and molecular weight play a pivotal role in the surface activity of Balangu and its fractions. Also, Balangu, PER-Balangu and SUPER-Balangu had structure features difference in finger-print area of FTIR spectrum.