No abstract

ABSTRACT:,B-(1-3)-D-glucan with (1-6) branching (L-FV-I) from Lentinus edodes in water was degraded into seven fractions of different molecular weights by ultrasonic irradiation. Weight-average molecular weight M w, radius of gyration , 112 and intrinsic viscosity [7]] of the ,B-o-glucan and its fractions in 0.5 M NaCl aqueous solution and dimethylsulfoxide (DMSO) were studied by multi-angle laser light scattering (MALLS), GPC combined with MALLS, and viscometry. M w dependence of [7]] for the glucan in 0.5 M NaCl aqueous solution was represented approximately by [7]] =7.69X 10-6 M / 32 (cm 3 g-1 ) at M w from 1.87 X 10 5 to 1.20 X 10 6 at 25°C. GPC chromatograms of the glucans in aqueous solution contained two peaks, a main peak corresponding to triple-stranded chains with molecular weight Mw,m, and small second peak corresponding to fragments of single chains with Mw, (about 20±5% content). Analysis of Mw m and ,m 112 in term of the known theory for wormlike chains yielded 2180± 100 nm -1, 120± 10 nm and 0.31 nm for.molar mass per unit contour length ML, persistence length q, and contour length h per main-chain glucose residue, respectively, which agree closely with theory data of triple-helical chains and reported parameters for triple-helix schizophyllan in 0.01 M NaOH aqueous solution. The ratios of Mw min 0.5 M NaCl to M win DMSO were calculated to be roughly 3. The predominant species of the glucan in 0.5 M NaCl ~queous solution exist as triple-helical chains with high rigidity, and in DMSO as single-flexible chains.

No abstract

Isolated corn hull arabinoxylan was dissolved in water and provided a clear solution. Plasticizer (glycerol, propylene glycol, or sorbitol) was added to the arabinoxylan solution at 0 -20 wt % (film dry weight), which was cast into stable films. Film thickness ranged from 22 to 32 m. Mechanical properties, moisture content, and water vapor permeability (WVP) were studied for the arabinoxylan-based films as a function of plasticizer concentration. Measured data for the corn hull arabinoxylan-based films were 13-18 wt % moisture content, 10 -61 MPa tensile strength, 365-1320 MPa modulus, 6 -12% elongation, and 0.23-0.43 ϫ 10 Ϫ10 g m Ϫ1 Pa Ϫ1 s Ϫ1 water vapor permeability. Plasticized arabinoxylan films produced in this study had lower WVPs than those of unplasticized films, which is likely attributable to the phenomenon known as antiplasticization. Scanning electron micrographs showed a homogeneous structure on film surfaces. Films containing sorbitol had the best moisture barrier properties. When grapes were coated with arabinoxylan and arabinoxylan/sorbitol films, weight loss rates of the fruit decreased by 18 and 41%, respectively, after 7 days.

No abstract