3.1. Chemical composition and monosaccharide analysis
Polysaccharide molecules are linked together by water molecules through hydrogen bonds in an aqueous solution. Adding ethanol into aqueous solution of polysaccharide initially dehydrate polysaccharides, enhance intra-molecular hydrogen bonding, cause conformational change and aggregation of polysaccharide molecules, and eventually leads to the precipitation of macromolecular chains, and the following addition of alcohol solvent gradually precipitates the molecular chains with relatively low MW, thereby achieving fractional precipitation of polysaccharides based on molecular structure (Jian et al., 2014). According to this procedure, two main fractions obtained from BSG, PER-BSG and SUPER-BSG.
The yield and chemical composition of BSG and its fractions are summarized in Table 1. The yield of BSG was ~10%. PER-BSG and Super-BSG fractions yield was 69% and 31%, respectively. There was no significant …show more content…
Molecular weight and Intrinsic viscosity
The molecular weight average and intrinsic viscosity [η] of BSG and its fraction was summarized in Table 3. The Huggins and Kraemer plots of BSG and its fractions were exhibited in Fig. 1. As expected, PER-BSG and SUPER-BSG showed the highest and lowest MW, respectively. MW of BSG was between PER-BSG and SUPER-BSG as BSG is composed of both fractions.
In order to determine the dilute Newtonian domain and the critical concentration (coil overlap parameter), master curve (plot of log (ηsp) against log C[η]) was plotted (Fig. 2) (Behrouzian et al., 2014). The master curve slope of BSG and its fraction were determined around 1.08-1.117 which shows all solutions were in the dilute domain. Berry number or dimensionless concentration (C[η]) also presents molecular entanglement when exceeds one and semi-dilute regime exist in the range of 1.0-10.0 (Graessley, 1974). C[η] was in the range of 0.22-0.98 for all samples, which confirmed absence of molecular entanglements (Table
Polysaccharide molecules are linked together by water molecules through hydrogen bonds in an aqueous solution. Adding ethanol into aqueous solution of polysaccharide initially dehydrate polysaccharides, enhance intra-molecular hydrogen bonding, cause conformational change and aggregation of polysaccharide molecules, and eventually leads to the precipitation of macromolecular chains, and the following addition of alcohol solvent gradually precipitates the molecular chains with relatively low MW, thereby achieving fractional precipitation of polysaccharides based on molecular structure (Jian et al., 2014). According to this procedure, two main fractions obtained from BSG, PER-BSG and SUPER-BSG.
The yield and chemical composition of BSG and its fractions are summarized in Table 1. The yield of BSG was ~10%. PER-BSG and Super-BSG fractions yield was 69% and 31%, respectively. There was no significant …show more content…
Molecular weight and Intrinsic viscosity
The molecular weight average and intrinsic viscosity [η] of BSG and its fraction was summarized in Table 3. The Huggins and Kraemer plots of BSG and its fractions were exhibited in Fig. 1. As expected, PER-BSG and SUPER-BSG showed the highest and lowest MW, respectively. MW of BSG was between PER-BSG and SUPER-BSG as BSG is composed of both fractions.
In order to determine the dilute Newtonian domain and the critical concentration (coil overlap parameter), master curve (plot of log (ηsp) against log C[η]) was plotted (Fig. 2) (Behrouzian et al., 2014). The master curve slope of BSG and its fraction were determined around 1.08-1.117 which shows all solutions were in the dilute domain. Berry number or dimensionless concentration (C[η]) also presents molecular entanglement when exceeds one and semi-dilute regime exist in the range of 1.0-10.0 (Graessley, 1974). C[η] was in the range of 0.22-0.98 for all samples, which confirmed absence of molecular entanglements (Table