Effect of deacetylation rate on gelation kinetics of konjac glucomannan

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.

Synthesis and Rheological Characterization of a Novel Salecan Hydrogel

Salecan (Sal) is a novel microbial polysaccharide. In the present research, thermal treatment was performed to fabricate Sal hydrogel. The effect of Sal concentration on water holding capacity, swelling properties, texture properties, and microstructure of the hydrogels was discussed. It was found that the equilibrium degree of swelling (EDS) of Sal hydrogels was above 1500%, inferred Sal was a highly hydrophilic polysaccharide. As Sal concentration increased from 3.5 to 8.0 wt%, the hardness increased from 0.88 to 2.07 N and the water hold capability (WHC) increased from 91.3% to 98.2%. Furthermore, the internal network structure of Sal hydrogel also became denser and more uniform. Rheological studies suggested that elastic hydrogel formed under the gelation process. All these results demonstrated that Sal hydrogel prepared by thermal treatment had good gelling properties, which opened up a new safe way for the preparation of Sal hydrogel and broadened the application range of Sal.

On the interaction of softwood hemicellulose with cellulose surfaces in relation to molecular structure and physicochemical properties of hemicellulose

The substantial part of the water-soluble hemicellulose fraction, obtained when processing cellulose to produce paper and other products, has so far been discarded. The aim of this work is to reveal the interfacial properties of softwood hemicellulose (galactoglucomannan, GGM) in relation to their molecular and solution structure. In this study the sugar composition of GGM was characterised by chemical analysis as well as 1D and 2D NMR spectroscopy. Previously it has been demonstrated that hemicellulose has high affinity towards cellulose and has the ability to alter the properties of cellulose based products. This study is focused on the interactions between hemicellulose and the cellulose surface. Therefore, adsorption to hydrophobized silica and cellulose surfaces of two softwood hemicellulose samples and structurally similar seed hemicelluloses (galactomannans, GMs) was studied with ellipsometry, QCM-D and neutron reflectometry. Aqueous solutions of all samples were characterized with light scattering to determine how the degree of side-group substitution and molecular weight affect the conformation and aggregation of these polymers in the bulk. In addition, hemicellulose samples were studied with SAXS to investigate backbone flexibility. Light scattering results indicated that GM polymers form globular particles while GGMs were found to form rod-like aggregates in the solution. The polysaccharides exhibit higher adsorption to cellulose than on hydrophobic surfaces. A clear correlation between the increase in molecular weight of polysaccharides and increasing adsorbed amount on cellulose was observed, while the adsorbed amount on the hydrophobic surface was fairly independent of the molecular weight. The obtained layer thickness was compared with bulk scattering data and the results indicated flat conformation of the polysaccharides on the surface.

Preparation and bioactivity of acetylated konjac glucomannan fibrous membrane and its application for wound dressing

Biomaterial-host interactions significantly affect tissue repair, which is modulated by macrophages. In this study, a polysaccharide, konjac glucomannan (KGM), was acetylated with different degrees of substitution (DS), and the acetylated KGM (AceKGM)-based fibrous membrane was designed to modulate the activity of macrophages for accelerating wound healing. AceKGM was biocompatible and easily dissolved in organic solvents. The adhesion force between Raw264.7 cells and the AceKGM substrate was quantitatively detected by atomic force microscopy (AFM). The enzyme-linked immunosorbent assay (ELISA) results showed that the AceKGM fibrous membrane enhanced macrophage expression of anti-inflammatory and pro-regenerative cytokines, and the DS of AceKGM significantly affected membrane bioactivity. The full-thickness mouse skin wound repair experiments indicated that the AceKGM-containing fibrous membranes significantly accelerated wound healing by promoting re-epithelialization, tissue remodeling, and collagen deposition. In summary, AceKGM-based fibrous membranes have potential as bioactive scaffolds for wound regeneration.

Effects of deacetylation of konjac glucomannan on the physico-chemical properties of surimi gels from silver carp (Hypophthalmichthys molitrix)

This work studied the effects of KGM with different degrees of deacetylation (DDs) on the physicochemical properties of silver carp (Hypophthalmichthys molitrix) surimi gels. Compared with KGM, deacetylated KGM (DKGM) weakened the water-holding capacity, but increased the gel strength of surimi gels. The storage modulus (G′) and loss modulus (G′′) of surimi showed an upward trend, and the aggregation rate of surimi with DKGM changed. The number of ionic bonds of mixed surimi gels increased on the whole, but those of hydrogen bonds declined; a hydrophobic interaction was the main driving force, and improved with the DDs of DKGM. FT-IR results indicated that the deacetylation of KGM had a slight influence on the secondary structure of the proteins. SDS-PAGE results showed that DKGM enhanced the intensity of the main heavy chains of myosin and actin. Examination of the network structure of the surimi gels revealed that DKGM might combine around the filaments of myofibrillar proteins like a rosary through hydrophobic interactions and hydrogen bonding. As a consequence, the myfibrillar protein aggregation was changed and the microstructures of the surimi became more compact and fibrous. The results indicated that the deacetylation of KGM led to an increase in hydrophobicity, which influenced the hydrophobic interaction of the myofibrillar proteins. As a result, the aggregation of the myofibrillar proteins was promoted and the physico-chemical properties of the surimi gel were improved.

This work studied the effects of KGM with different degrees of deacetylation (DDs) on the physicochemical properties of silver carp (Hypophthalmichthys molitrix) surimi gels.

Mannans: An overview of properties and application in food products

This review aims to emphasize the occurrence and abundant presence of mannans in nature, their classification, structural differences and significance in food and feed industry. With rising demand from the consumers' end for novel natural foods, usage of galactomannan and glucomannan has also increased alternatively. Non toxicity of mannans permits their usage in the pharmaceutical, biomedical, cosmetics, and textile industries. In the food industry, mannans have various applications such as edible films/coating, gel formation, stiffeners, viscosity modifiers, stabilizers, texture improvers, water absorbants, as prebiotics in dairy products and bakery, seasonings, diet foods, coffee whiteners etc. Applications and functions of these commonly used commercially available mannans have therefore, been highlighted. Mannans improve the texture and appeal of food products and provide numerous health benefits like controlling obesity and body weight control, prebiotic benefits, constipation alleviaton, prevent occurrence of diarrhea, check inflammation due to gut related diseases, management of diverticular disease management, balance intestinal microbiota, immune system modulator, reduced risk of colorectal cancer etc. Mannan degrading enzymes are the key enzymes involved in degradation and are useful in various industrial processes such as fruit juice clarification, viscosity reduction of coffee extracts etc. besides facilitating the process steps and improving process quality.

Characteristics of glucomannan isolated from fresh tuber of Porang (Amorphophallus muelleri Blume)

Porang is a potential source of glucomannan. This research objective was to find a direct glucomannan isolation method from fresh porang corm to produce high purity glucomannan. Two isolation methods were performed. In first method, sample was water dissolved using Al₂(SO₄)₃ as flocculant for 15 (AA15) or 30 (AA30) minutes with purification. In second method, sample was repeatedly milled using ethanol as solvent and filtered for 5 (EtOH5) or 7 (EtOH7) times without purification. The characteristics of obtained glucomannan were compared to those of commercial porang flour (CPF) and purified konjac glucomannan (PKG). High purity (90.98%), viscosity (27,940 cps) and transparency (57.74%) of amorphous glucomannan were isolated by EtOH7. Ash and protein level significantly reduced to 0.57% and 0.31%, respectively, with no starch content. Water holding capacity (WHC) of EtOH7 glucomannan significantly enhanced, whereas its solubility was lower than those of PKG due to its ungrounded native granular form.

Polysaccharide nanoparticles for protein and Peptide delivery: exploring less-known materials

Finding adequate carriers for protein and peptide delivery has become an urgent need, owing to the growing number of macromolecules identified as having therapeutic potential. Nanoparticles have emerged in the field as very promising vehicles and much work has been directed to testing the capacity of different materials to compose the matrix of these carriers. Natural materials and, specifically, polysaccharides have been taking the forefront of the challenge, because of several favoring properties that include the higher propensity to exhibit biodegradability and biocompatibility, and also the high structural flexibility. The majority of works found in the literature regarding polysaccharide nanoparticles uses very popular materials like chitosan or hyaluronic acid. This review is aimed at describing and exploring the potential of polysaccharides that are not so well known or that are less explored. For those, the main properties will be described, together with an overview of the reported applications as nanoparticle matrix materials.

Konjac glucomannan-based hydrogel with hyaluronic acid as a candidate for a novel scaffold for chondrocyte culture

Chondrocytes were cultured using konjac glucomannan (KGM) and hyaluronic acid (HA) as a scaffold for cartilage regeneration. They were subsequently compared with scaffolds produced using agarose hydrogels. Chondrocytes derived from Japanese white rabbits were cultured: 2.0 x 10(5) cells were seeded on KGM containing hyaluronic acid (KGM/HA) and agarose and cultured for 5 days. Their viability was assayed using WST-8 procedures; the ultimate stress and modulus of elasticity of each construct was calculated. After 3 days of cultivation, mRNA in chondrocytes, such as collagen types I and II and aggrecan, were measured using RT-PCR. Both chondrocyte-seeded constructs were stained with safranin O/fast green and were evaluated histologically. Chondrocyte viability decreased concomitantly with increasing KGM/HA or agarose concentration and with culture time. Cell viability in 2% agarose was significantly lower than that in 2% KGM/HA on the third and fifth days (p < 0.05). The primary elastic modulus increased concomitantly with increasing polysaccharide concentration. Elastic moduli of 2% KGM/HA with chondrocytes (0.389 +/- 0.119 N/mm(2)) showed little difference from those without chondrocytes (0.283 +/- 0.243 N/mm(2)), although those of 2% agarose with chondrocytes (0.403 +/- 0.094 N/mm(2)) were significantly lower than those without chondrocytes (0.736 +/- 0.227 N/mm(2); p < 0.05). Collagen type II mRNA expression was higher in KGM/HA and agarose than in monolayer cultures, although KGM/HA had lower aggrecan mRNA expression levels than did agarose. Histological tests of KGM/HA-chondrocyte constructs revealed chondrocyte aggregation and proteoglycan production in the pericellular region. The results show that KGM/HA might be useful for chondrocyte culture.