Molecular weight effects on gelation and rheological properties of konjac glucomannan-xanthan mixtures

Regulation of glycose and lipid metabolism and application based on the colloidal nutrition science properties of konjac glucomannan: A comprehensive review

The physicochemical properties of dietary fiber in the gastrointestinal tract, such as hydration properties, adsorption properties, rheological properties, have an important influence on the physiological process of host digestion and absorption, leading to the differences in satiety and glucose and lipid metabolisms. Based on the diversified physicochemical properties of konjac glucomannan (KGM), it is meaningful to review the relationship of structural characteristics, physicochemical properties and glycose and lipid metabolism. Firstly, this paper bypassed the category of intestinal microbes, and explained the potential of dietary fiber in regulating glucose and lipid metabolism during nutrient digestion and absorption from the perspective of colloidal nutrition. Secondly, the modification methods of KGM to regulate its physicochemical properties were discussed and the relationship between KGM's molecular structure types and glycose and lipid metabolism were summarized. Finally, based on the characteristics of KGM, the application of KGM in the main material and ingredients of fat reduction food was reviewed. We hope this work could provide theoretical basis for the study of dietary fiber colloid nutrition science.

Designing cellulose hydrogels from non-woody biomass

Hydrogels are an attractive system for a myriad of applications. While most hydrogels are usually formed from synthetic materials, lignocellulosic biomass appears as a sustainable alternative for hydrogel development. The valorization of biomass, especially the non-woody biomass to meet the growing demand of the substitution of synthetics and to leverage its benefits for cellulose hydrogel fabrication is attractive. This review aims to present an overview of advances in hydrogel development from non-woody biomass, especially using native cellulose. The review will cover the overall process from cellulose depolymerization, dissolution to crosslinking reaction and the related mechanisms where known. Hydrogel design is heavily affected by the cellulose solubility, crosslinking method and the related processing conditions apart from biomass type and cellulose purity. Hence, the important parameters for rational designs of hydrogels with desired properties, particularly porosity, transparency and swelling characteristics will be discussed. Current challenges and future perspectives will also be highlighted.

Ultrasonic Degradation of Konjac Glucomannan and the Effect of Freezing Combined with Alkali Treatment on Their Rheological Profiles

The effect of freezing combined with alkali treatment on physicochemical property of konjac glucomannan (KGM) with different molecular weight was investigated in this work. The properties and structure of degraded KGM was characterized by means of intrinsic viscosity measurement, atomic force microscope (AFM) and Fourier transformation infrared (FT-IR). The results suggested that the intrinsic viscosity of KGM solution gradually decreased during the ultrasonic treatment. The AFM observation indicated that KGM with lower viscosity average molecular weight had smaller height and lateral diameter of molecules. The main repeating units of the KGM chain could not be destroyed no matter how long the KGM was sonicated. Rheometrical studies revealed that with increasing alkali concentration from 0% to 0.36%, both viscosities and shear stress of deacetylated konjac glucomannan (Da-KGM) system were increased and moduli G' were substantially higher in either freezing or unfreezing samples. Da-KGM system performed a solid-like behavior (G' > G'') along the frequency range after freezing treatment. With increasing sonication time, both viscosity and shear stress of unfreezing samples were decreased while had an inverse effect for freezing treated samples. The modulus G' and G'' declined for unfreezing samples but rise significantly for freezing treated samples with increase of sonication time.

Interaction between xanthan gum and cationic cellulose JR400 in aqueous solution

The electrostatic and hydrogen bonding interactions between xanthan gum (XG) and semisynthetic cationic cellulose (JR400) in aqueous solution are investigated via stability map, FT-IR spectra, thermogravimetric analysis, potentiometric measurement and rheological method. The stability map shows three regions, a stable region with XG as the major component, a flocculated region and another stable region with JR400 as the major component. The stability of mixing system depends on both the concentration fraction of JR400 (fJR) and the overlapping concentrations of these two polymers. In the region near the stoichiometric fJR, the mixture shows stoichiometric flocculation, which is independent of the total polymer concentration. However, in the regions away from the stoichiometric fJR, the mixtures are stable when the concentration of major polymer component is higher than its overlapping concentration. In stable regions, the electrostatic and hydrogen bonding interactions can enhance the viscosity of mixing system at appropriate fJR values.