Preparation of full-bio-based nanofiltration membranes
JOURNAL OF MEMBRANE SCIENCE
Authors: Rasool, Muhammad Azam; Vankelecom, Ivo F. J.
Abstract
Cellulose acetate (CA) as polymer, glycerol derivatives (namely triacetin, diacetin, monoacetin or glycerolformal) as solvents and 2-methyltetrahydrofuran (2-MeTHF) as co-solvent were selected as bio-based ingredients for the preparation of full-blo-bascd nanofiltration membranes via non-solvent induced phase separation (NIPS). Membrane performance was investigated using an aqueous rose bengal (1017Da) solution (RB/H2O) as feed. Membrane morphologies were characterized using SEM (scanning electron microscopy). Both kinetic and thermodynamic aspects of the phase inversion process were studied in detail to gain more insight in the membrane formation process. When implementing a 90s evaporation step prior to coagulation, rejection increased with increasing 2-MeTHF concentration in the casting solution in the case of diacetin and triacetin solvents. In the case of monoacetin and glycerol-formal based casting solutions, evaporation had a less significant impact on RB rejection even though the same volatile co-solvent was used. The best membranes were finally obtained using diacetin as a solvent and 2-MeTHF as co-solvent with permeances ranging from 5.5 to 12.8 L/m(2) h bar for membranes with >90% RB rejections.
Effects of xanthan and konjac gums on pasting, rheology, microstructure, crystallinity and in vitro digestibility of mung bean resistant starch
FOOD CHEMISTRY
Authors: Lin, Siyu; Liu, Xiane; Cao, Yao; Liu, Suchen; Deng, Danwen; Zhang, Jinsheng; Huang, Ganhui
Abstract
The effects of different concentrations of xanthan and konjac gums on the pasting, rheological properties, microstructure, crystallinity, and digestibility of mung bean resistant starch (MRS) were investigated. Based on the results of pasting properties, the adjunction of gums increased the peak, breakdown, and final viscosities of resistant starch. Compared with resistant starch, the addition of gum significantly increased the K value and dynamic moduli (G, G '') of MRS with increasing gum concentration. This finding indicates that the mixtures had higher viscoelasticity. Mixtures with xanthan gum of MRS had larger starch particle compared with MRS, as revealed by SEM. All starches showed B and V-type crystallinity with high crystallinity. MRS had the highest summation of resistant starch (RS) and slowly digestible starch (SDS) of 71.89%. MRS had the lowest hydrolysis rate, which obviously decreased from 71.89% to 57.71% with increasing konjac gum from 0 to 0.30%.