Konjac Glucomannan (KGM), Deacetylated KGM (Da-KGM), and Degraded KGM Derivatives: A Special Focus on Colloidal Nutrition

Physicochemical and rheological properties of konjac glucomannan and its mixed gels with κ-carrageenan: Effect of deacetylation by L-arginine

Konjac glucomannan (KGM) is a natural functional polysaccharide, and deacetylation (removing acetyl groups) impacts its physicochemical and gel properties. In order to study KGM's gel properties and explore new deacetylation modifiers, three deacetylated konjac glucomannan (DKGM) with different deacetylation degrees (DD, 17.51 %, 35.41 %, and 54.52 %) were prepared using L-arginine. Results showed that L-arginine deacetylated and retained the main structure and high molecular weight of KGM. Solubility decreased from 85.38 % to 81.17 %, transparency decreased from 38.52 % to 35.73 %, water absorbing and swelling slowed down, and molecular morphology changed from chain structures to micelle-like aggregates after deacetylation. Dynamic viscoelastic analysis showed that deacetylation facilitated the formation of the entangled network structure of KGM. The strength of konjac glucomannan and κ-carrageenan mixed gels increased after deacetylation, and this enhancement was mainly through hydrogen bonds and hydrophobic interactions. These findings will provide theoretical guidance for the application of KGM.

A bigel co-delivering highly hydrophilic and hydrophobic natural compounds for enhanced ulcerative colitis therapy

Bigel, formed by high-speed shearing of hydrogel and oleogel, is suited to deliver both lipophilic and hydrophilic active compounds. Patchouli oil and paeoniflorin, despite their potential in treating ulcerative colitis, face challenges due to patchouli oil's poor aqueous solubility and paeoniflorin's high solubility but low permeability. In this study, we developed an oral colon-targeted bigel system to co-deliver patchouli oil and paeoniflorin for treating ulcerative colitis. Patchouli oil served as both a therapeutic agent and an oil phase (excipient). The bigel system enhanced mechanical stability, prolonging retention at the colon and enabling effective colon-targeted drug delivery. Compared to oleogel, bigel significantly alleviated symptoms in DSS-induced colitis in mice, reduced inflammatory cytokine release, repaired intestinal mucosal damage, and regulated immune cell populations in the gut. The combination of patchouli oil and paeoniflorin in the bigel exerted a synergistic effect on ulcerative colitis treatment. This work underscores the efficacy of bigel in delivering a combination of hydrophilic and lipophilic drugs, offering a novel strategy for enhanced drug delivery in ulcerative colitis. It also provides a delivery platform technology for volatile oils.

Antioxidant activity of differently sized and sulfated konjac glucomannan fragments prepared by the relay strategy

Konjac glucomannan (KGM) is a polysaccharide with potential medical and functional properties. Here, the antioxidant and cytoprotective effects of sulfated and differently sized KGM fractions were investigated using various in vitro assays. The sulfated KGMs (SKGMs) were prepared via a relay strategy. First, Vitamin C (Vc)-H2O2 degradation was employed to obtain three soluble KGM fractions with different molecular weights. Second, nine KGM derivatives with varying sulfate content were obtained by the sulfur trioxide-pyridine method. The scavenging of DPPH, superoxide, and hydroxyl radicals was measured in vitro. The antioxidant activity of SKGM correlated positively with sulfate content. SKGM-I-2 displayed the most potent radical scavenging activity. Its purification by cellulose DEAE-52 column chromatography yielded four homogeneous fractions (SKGM-I-2a, SKGM-I-2b, SKGM-I-2c, and SKGM-I-2d). Pretreatment with SKGM-I-2d increased the viability of RAW264.7 cells exposed to H2O2. Moreover, SKGM-I-2d significantly increased the activity of superoxide dismutase and catalase, as well as the levels of glutathione, while regulating the expression of Keap1, Nrf2, and HO-1 in RAW264.7 cells. The present study suggests that SKGM-I-2d protects RAW264.7 cells against H2O2-induced oxidative injury through the activation of the Nrf2/Keap1 signaling pathway. These results provide a scientific basis for future studies linking the structural and functional features of KGM.

Calcium alginate-cross-linked deacetylated konjac glucomannan-based double network hydrogels: Construction, characterizations and gelation kinetics

Deacetylated Konjac Glucomannan (DKGM) hydrogels frequently fail to meet commercial standards because of their weak gel strength and low mechanical characteristics. In this regard, we successfully constructed DKGM and calcium alginate (CA) double network hydrogels (DKGM/CA DNs) through the two-step sequential network formation technique for the first time. The microstructure, gel properties and gel kinetics of DKGM/CA DNs were investigated in multiple dimensions. Notably after the introduction of CA gel network into DKGM hydrogels, the system's gel network pores became dense, the water freedom decreased, and the gel strength, hardness, gumminess and other properties were 10-25 times higher than pure DKGM hydrogels. Further gel kinetics analysis showed that the presence of sodium alginate (SA) increased the gelation rate of DKGM during the gelation process, shorten the sol-to-gel time, and reduced the complex modulus of the gel system. In contrast, the presence of DKGM hydrogels would hinder the penetration and diffusion of Ca2+ solution, thus slowing down the crosslinking rate of SA and Ca2+. In summary, this study provides a new solution for improving the mechanical properties of DKGM hydrogels in a green and efficient manner.

Improvement of soybean protein isolate/konjac glucomannan-seaweed polysaccharide-based connective tissue simulants: effects of pH and water mobility on gel structure and gelling mechanism

Hydrogels are considered to have good potential to mimic connective tissue. In this study, the mechanical properties and thermal stability of protein-polysaccharide composite hydrogels were enhanced by moisture and acid-base modulation in an attempt to overcome the application limitations. The results of texture profile analysis (TPA) and compression experiments showed that the appropriate outward migration of moisture significantly improved the gel's mechanical properties. Rheological analysis showed that the gel exhibited optimal mechanical properties under an alkaline environment and, combined with the differential scanning calorimetry (DSC) results, excellent thermal stability was observed in the pH 10.5 sample group. Furthermore, magnetic resonance imaging (MRI) and scanning electron microscopy (SEM) results showed that the alkaline environment was also conducive to the formation of a denser gel network structure, and the outward migration of water led to a more orderly and uniform structure. Fourier transform infrared spectroscopy (FTIR) results showed that hydrogen bonding also played a major role in the formation of the cellular network structure of the gel. These findings demonstrate the positive contribution of moisture and pH modulation to the processing and edible property enhancement of animal connective tissue-mimicking structure and provide a theoretical basis for the regulation of hydrogel properties.

Extraction, structure, activity and application of konjac glucomannan

Konjac is a perennial herbaceous plant from the Araceae family's Amorphophallus genus. It has high nutritional, health, and pharmacological values. It contains various bioactive components, the most notable of which is konjac glucomannan, which has several biological roles, including efficiently fighting diabetes, exerting prebiotic activity, containing antioxidant capacity, modulating immunological function, and demonstrating anti-cancer potential. Currently, the konjac glucomannan (KGM) research mainly focuses on packaging film, gel characteristics, efficacy, and evaluation. However, the extraction, underlying portrayal, derivatization, and action of KGM are seldom detailed. Herein, the utilization of konjac as an unrefined substance was surveyed, meaning to give extensive and orderly recombinant data on the extraction, decontamination, structure, natural movement, derivatization, and use of KGM to provide a full play to the interesting gelatinate, biocompatibility, high viscosity and other properties of KGM. It provided a theoretical basis for further developing the konjac glucomannan food industry, pharmaceutical field, and other fields.

Functional Characterization of a Highly Efficient Endoglucanase from Bacillus licheniformis BJ2022 and Its Application in the Preparation of Low-Molecular-Weight Konjac Glucomannan

Endoglucanases may not only act on β-1,4-linkages in β-glucan but also target d-glucose in glucomannan, which can expand their utility in the preparation of prebiotics. In this study, a highly efficient endoglucanase (BlGH5) from Bacillus licheniformis BJ2022 was expressed and characterized. BlGH5 exhibited the highest activity at pH 7.0 and 60 °C. It maintained over 80% activity at pH 4.0-7.0 and 30-60 °C. BlGH5 specifically cleaved β-1,4-glycosidic bonds linked to d-glucose. Site-directed mutagenesis results suggested that Arg91, Asn167, Glu168, Trp206, His228, Tyr230, Ser263, and Trp290 are key residues for its binding and catalytic activity. Moreover, BlGH5 displayed high activity against konjac glucomannan (KGM), indicating that BlGH5 could be used to prepare low-molecular-weight konjac glucomannan (KGM-L). Based on the physicochemical properties of KGM and KGM-L, KGM-L was characterized by reduced molecular weight and viscosity. Fecal fermentation experiments demonstrated that KGM and KGM-L could promote the production of short-chain fatty acids (SCFAs). Still, KGM-L was more conducive to the growth of the gut probiotics. In conclusion, we identified an endoglucanase for the degradation of KGM. Results indicated that KGM-L would have superior prebiotic effects. Thus, our study provides a basis for the future development and application of KGM-L as a prebiotic.

Interaction mechanism, fabrication strategies, and advanced applications of konjac glucomannan-based mixed polysaccharide systems

Due to its high viscoelasticity and positive health benefits, konjac glucomannan (KGM)-based mixed polysaccharide systems are widely applied in food processing and pharmaceuticals. However, a knowledge gap exists between the relationship between KGM interactions with different polysaccharides and the resulting food processing properties and health benefits. This review elaborately aims to address this research gap by analyzing the literature on the updated KGM-based binary thermodynamic compatibility systems, classified and discussed according to the basic gel models. Further fabrication and tailored strategies for improving gel properties and the resulting changes in food production and processing, nutrient digestion and absorption, and health benefits are explored. The development of future food should combine with structural food theory and colloidal nutrition based on soft condensed matter physics, intersected chemistry, biology, and engineering to achieve technological innovation.

Fabrication of soy protein isolate-konjac glucomannan emulsion gels to mimic the texture, rheological behavior and in vitro digestion of pork fat

Fats are essential nutrients, but excessive intake can lead to obesity and certain cardiovascular diseases. In this study, an emulsion gel was prepared using alkali heat treatment with soy protein isolate (SPI) and konjac glucomannan (KGM) as a fat substitute, while pork fat was used as the control. Gel strength, rheological properties, and water holding capacity of soy protein isolate-konjac glucomannan (SPI-KGM) emulsion gel improved progressively with higher KGM content. For instance, the SPI-5 % KGM emulsion gel exhibited a hardness of 384.77 g, a gel strength of 9.62 kPa, and a water-holding capacity of 98.03 %, comparable to pork fat in terms of texture and moisture retention. Furthermore, scanning electron microscopy images revealed that a more compact and regular emulsion gel network was formed with increasing KGM concentration. Therefore, this SPI-KGM emulsion gel shows promise as a substitute for pork fat and holds great potential for developing plant-based meat products.

Gel properties of sheep's hoof gelatin-dietary polysaccharide interpenetrating polymer network complex gels with application in low fat lamb patties

In order to explore new fat substitutes, we compared three dietary polysaccharides Pectin(PEC), Inulin (INU), and Konjac glucomannan (KGM) compounded with sheep hoof gelatin using different cross-linking methods [transglutaminase (Tg) enzyme; Tg enzyme & Ca2+] for the preparation of Semi-interpenetrating polymer network (Semi-IPN) and fully interpenetrating polymer network (IPN) gels. The optimal ratio was determined by comprehensively evaluating the addition of hydrogel to the lamb patties at different ratios. The results showed that PEC-IPN exhibited superior stability and textural properties compared to the Semi-IPN gels and control gels in each group. In addition, replacing 80 % of the fat in the lamb patties with PEC-IPN significantly improved the quality stability during storage, without affecting the sensory quality. Therefore, PEC-IPN instead of lamb patty fat offers a new approach for consumers.

Konjac glucomannan-based hydrogels with tunable mechanical strength and frictional resistance for biomedical applications

Hydrogels with favorable biocompatibility are regarded as ideal biomedical materials. However, their poor mechanical and tribological properties limit their further clinical applications. Konjac glucomannan (KGM), a safe natural polysaccharide, has the potential to bridge this gap by regulating the mechanical and tribological properties of hydrogels. This work prepares physical-physical and physical-chemical composite hydrogels to validate the enhancement effect of KGM. Within both types of hydrogels, KGM macromolecules aggregate and regulate their compression properties. As an additive, KGM enhances the compressive strength of polyacrylamide (PAM) hydrogel from 140.78 KPa to 638.79 KPa and reduces the coefficient of friction (CoF) of polyvinyl alcohol (PVA) and PAM substrates by 52.57 % and 60.60 %, respectively. Moreover, KGM exhibits excellent biocompatibility. In summary, KGM emerges as a safe and effective candidate for regulating the mechanical and tribological properties of hydrogels, thereby demonstrating great potential for further biomedical applications.

Biochemical characterization of the catalytic domain from a novel hyperthermophilic β-glucanase and its application for KOS production

Konjac oligosaccharide (KOS) exhibits various biological activities, and hyperthermophilic β-glucanases offer many advantages for KOS production from konjac glucanmannan (KGM). In this study, a novel β-glucanase, EG003, belonging to the glycosyl hydrolase (GH) subfamily 5_1, was predicted from the genome of the a Thermus strain. The recombinant EG003 and its catalytic domain, EG003A, were successfully expressed and characterized. EG003A displayed maximum activity at 95 °C and pH 8.0, with a specific activity of 1047.6 U/mg and retained approximately 50 % activity after 6 h at 90 °C. The enzyme exhibited both β-1,4-glucanase and β-1,3-1,4-glucanase activity with KGM and sodium carboxymethylcellulose (CMC), lichenan and oat β-glucan as substrates. Degree of polymerization (DP) 3 was the major oligosaccharide from the hydrolysis of KGM, while DP3 and DP4 were predominant products from the hydrolysis of oat β-glucan. Molecular docking analyses revealed that the catalytic mechanism of EG003A is consistent with those of other reported GH5_1 β-glucanases. Additionally, the viscosity of 500 mL solution of 1 % KGM decreased rapidly from 31,193 mPa.s to 4.50 mPa.s in 3 min with 30 U EG003A. This study provides an efficient hyperthermophilic β-glucanase with promising application for KOS production.

Fenugreek gum improves the rheological properties of konjac glucomannan in dynamic simulated digestion system and delays its gastric emptying

The physicochemical properties of konjac glucomannan (KGM) are impaired in the harsh gastrointestinal tract, which may reduce its effectiveness in physiological functions. In this paper, fenugreek gum (FG) with high water holding capacity and stability was used as a gastric protectant for KGM, and the effects of the KGM-FG complexes with different composite ratios on gastric emptying were researched by in vitro dynamic simulated gastric digestion system. The results showed that FG significantly enhanced the delayed gastric emptying properties of KGM. Adding FG reduced the apparent viscosity, flow behavior, and mechanical properties of KGM. The simulated gastric fluid (SGF) decreased the apparent viscosity of the KGM-FG complex and increased the microstructure network density of the KGM-FG complex compared with the water system. FG helped the structure of the KGM-FG complexes become more stable and trapped more water in the stomach. The KGM-FG complex with high viscosity, mechanical modulus, and frictional resistance in a dynamic simulated digestion system increased gastric retention. The KGM-FG complex with a composite ratio 5:5 showed the best performance and a potential satiety-enhancing property. The results provided a theoretical basis for designing satiety food formulations that help control energy intake and body weight.

Alcogels based on secalin and konjac glucomannan composites for the controlled release of curcumin

Alcogel has been increasingly applied in foods, cosmetics, and pharmaceutical industries. However, their application is limited by the lack of efficient biomacromolecule-based gelators. Herein, we present our discovery of secalin, a prolamin from rye, combined with konjac glucomannan (KGM) as novel food-grade gelators. Secalin-KGM (SK) alcogels could be prepared by directly cooling down their alcoholic solution, resulting in a thermo-induced sol-gel transition. SK gels (5 w/v % in 50 v/v % ethanol solution) exhibited diverse microstructural features and tunable mechanical properties that could be adjusted by varying the ratio of secalin to KGM. Microscopic images showed that when blended at a certain ratio, a homogeneous porous network is formed due to strong intermolecular interactions. Moreover, the SK gels exhibited a great ability to controllably release curcumin under simulated gastrointestinal tract conditions. The findings provide a novel plant protein-polysaccharide system to develop alcogels with tunable gelling properties and digestibility for functional food and drug delivery applications.

A Novel Konjac Powder with High Compressibility, High Water-Holding Capacity, and High Expansion Force

The inherent physico-chemical properties of commercial konjac powders often limited their application across various industries. While existing modification techniques had produced konjac powders with diverse physical attributes, these methods were frequently associated with high costs and environmental concerns. Hence, there was a critical need to develop a cost-effective, environmentally friendly, and straightforward method for modifying konjac powders. This study investigated the effects of limited moisture modification combined with drying methods on the key physical properties of konjac powders using a comprehensive set of analytical techniques. The results demonstrated that the processed konjac powders exhibited enhanced hydration properties and compressibility. Notably, moisture modification at 54.04%, combined with vacuum freeze-drying (VFD), resulted in konjac powders with a loose, porous microstructure (porosity: 75.54%) and good tablet-forming properties, significantly exceeding that of the control group. Additionally, the combination of vacuum drying (VD, 17 h) and VFD (2 h) significantly improved the water-holding capacity (154.54 g/g) and expansion force (109.97 mL/g) of the konjac powders. This study provided a sustainable, safe, economical, and easily scalable method for tailoring the physical properties of konjac powders. The modified konjac powders developed here were suitable for applications requiring high hydration properties or direct powder compression.

Deacetylation enhances the structure and gelation properties of konjac glucomannan/soy protein isolate cold-set gels

This study aimed to investigate the effect of the deacetylated konjac glucomannan (DKGM), with varying degree of deacetylation (DD), on the physicochemical and structural properties of transglutaminase-induced soy protein isolate (SPI) cold-set gels. Compared with native konjac glucomannan (KGM), DKGM significantly enhanced the gel strength, water-holding capacity, and thermal stability of the composite gels, with DK3 (DKGM with 65.85 % deacetylation) showing the most significant improvement. The secondary and tertiary structures of SPI in the DK3 group were the most stable. Compared with the KGM group, the DK3 group showed a 58.32 % increase in hydrophobic interaction and a 37.98 % decrease in free sulfhydryl content. The microstructure results demonstrated that DK3 was uniformly dispersed within the SPI network, promoting the formation of a continuous and dense network structure. This was mainly due to DK3 having a moderate particle size and low viscosity. Therefore, DKGM with a moderate DD is conducive to forming a more ordered and dense gel network structure, imparting optimal gel performance to the SPI cold-set gel.

Plant Taxa as Raw Material in Plant-Based Meat Analogues (PBMAs)-A Patent Survey

Background/Objectives: The environmental problems associated with meat production, the pain and distress of animals, and health problems have contributed to the increased appreciation of meat alternatives. Methods: The review of patented inventions presenting plant-based meat analogues (PBMAs) issued in the years 2014-2023 was conducted according to PRISMA statements across the ISI Web of Science, as well as Google Patents and Espacenet Patent Search engines. Results: The analysis of 183 patents showed an increase in patent numbers in the years 2020-2022, with the greatest number of patents developed by teams consisting of two authors. The authors and patent applicants were mainly affiliated with the United States, while Société des Produits Nestlé S.A. emerged as the leader among applicant institutions. The International Patent Classification (IPC) codes were given to 177 patents, which were mainly classified as Human Necessities (Section A). In total, inventors mentioned 184 taxa, including 28 genera, 1 section, 144 species, 5 subspecies and 6 varieties of vascular plants. The majority of taxa showed a high edibility rating and belonged to perennials, mainly herbaceous plants representing the families Fabaceae, Poaceae and Brassicaceae. The analysis of patents showed that plants are a promising source of protein, lipids, fibre, polyphenols, starch and gum in meat analogues. At the same time, the noticed slight use of numerous taxa, despite the substantial content of valuable constituents as well as high edibility rates, presumably might be caused by their underutilization in numerous regions of the world. Conclusions: The direction of future studies should focus on searching for novel plant-based meat analogues based on underutilized, promising plant sources and investigations of their usefulness.

Insight into konjac glucomannan-retarding deterioration of steamed bread during frozen storage: Quality characteristics, water status, multi-scale structure, and flavor compounds

Konjac glucomannan (KGM), a water-soluble hydrocolloid, holds considerable potential in the food industry, especially for improving the quality and nutritional properties of frozen products. This study explored the alleviative effect of KGM on the quality characteristics, water status, multi-scale structure, and flavor compounds of steamed bread throughout frozen storage. KGM significantly improved the quality of steamed bread by slowing down the decrease in water content and the increase in water migration while maintaining softness and taste during frozen storage. Notably, KGM also delayed amylopectin retrogradation and starch recrystallization, thus preserving the texture and structure of the steamed bread. At week 3, the microstructure of the steamed bread with 1.0 % KGM remained intact, with the lowest free sulfhydryl content. Additionally, heat map analysis revealed that KGM contributed to flavor retention in steamed bread frozen for 3 weeks. These results indicate that KGM holds promise as an effective cryoprotectant for improving the quality of frozen steamed bread.

In the process of polysaccharide gel formation: A review of the role of competitive relationship between water and alcohol molecules

Polysaccharides have emerged as versatile materials capable of forming gels through diverse induction methods, with alcohol-induced polysaccharide gels demonstrating significant potential across food, medicinal, and other domains. The existing research mainly focused on the phenomena and mechanisms of alcohol-induced gel formation in specific polysaccharides. Therefore, this review provides a comprehensive overview of the intricate mechanisms underpinning alcohol-triggered gelation of different polysaccharides and surveys their prominent application potentials through rheological, mechanical, and other characterizations. The mechanism underlying the enhancement of polysaccharide network structures by alcohol is elucidated, where alcohol displaces water to establish hydrogen bonding and hydrophobic interactions with polysaccharide chains. Specifically, alcohols change the arrangement of water molecules, and the partial hydration shell surrounding polysaccharide molecules is disrupted, exposing polysaccharides' hydrophobic groups and enhancing hydrophobic interactions. Moreover, the pivotal influences of alcohol concentration and addition method on polysaccharide gelation kinetics are scrutinized, revealing nuanced dependencies such as the different gel-promoting capabilities of polyols versus monohydric alcohols and the critical threshold concentrations dictating gel formation. Notably, immersion of polysaccharide gels in alcohol augments gel strength, while direct alcohol addition to polysaccharide solutions precipitates gel formation. Future investigations are urged to unravel the intricate nexus between the mechanisms underpinning alcohol-induced polysaccharide gelation and their practical utility, thereby paving the path for tailored manipulation of environmental conditions to engineer bespoke alcohol-induced polysaccharide gels.

Genome-wide analysis of the Amorphophallus konjac AkCSLA gene family and its functional characterization in drought tolerance of transgenic arabidopsis

BACKGROUND

Amorphophallus konjac (A. konjac), a perennial tuberous plant, is widely cultivated for its high konjac glucomannan (KGM) content, a heteropolysaccharide with diverse applications. The cellulose synthase-like (CSL) gene family is known to be a group of processive glycan synthases involved in the synthesis of cell-wall polysaccharides and plays an important role in the biological process of KGM. However, in A. konjac the classification, structure, and function of the AkCSLA superfamily have been studied very little.

RESULTS

Bioinformatics methods were used to identify the 11 AkCSLA genes from the whole genome of Amorphophallus konjac and to systematically analyze their characteristics, phylogenetic evolution, promoter cis-elements, expression patterns, and subcellular locations. Phylogenetic analysis revealed that the AkCSLA gene family can be divided into three subfamilies (Groups I- III), which have close relationships with Arabidopsis. The promoters of most AkCSLA family members contain MBS elements and ABA response elements. Analysis of expression patterns in different tissues showed that most AkCSLAs are highly expressed in the corms. Notably, PEG6000 induced down-regulation of the expression of most AkCSLAs, including AkCSLA11. Subcellular localization results showed that AkCSLA11 was localized to the plasma membrane, Golgi apparatus and endoplasmic reticulum. Transgenic Arabidopsis experiments demonstrated that overexpression of AkCSLA11 reduced the plant's drought tolerance. This overexpression also inhibited the expression of drought response genes and altered the sugar components of the cell wall. These findings provide new insights into the response mechanisms of A. konjac to drought stress and may offer potential genetic resources for improving crop drought resistance.

CONCLUSION

In conclusion, the study reveals that the AkCSLA11 gene from A. konjac negatively impacts drought tolerance when overexpressed in Arabidopsis. This discovery provides valuable insights into the mechanisms of plant response to drought stress and may guide future research on crop improvement for enhanced resilience.

Building covalent crosslinks of carboxymethyl konjac glucomannan with boronic ester bonds for fabricating multimodal hydrogel sensor

As the derivative of konjac glucomannan (KGM), carboxymethyl konjac glucomannan (CMK) has attracted increasing attention in the polysaccharide hydrogel fields with the aim of improving the performance related to drug delivery and release. In this study, we prepared a CMK-based hydrogel with dual characteristic crosslinks, and unlocked new applications of this type of hydrogel in soft sensor fields. CMK and poly (vinyl alcohol) were used as substrates, and physical crosslinks were constructed via the freeze-thawing treatments and covalent crosslinks were built via the boronic ester bonding. As-prepared hydrogel possessed significantly improved mechanical performance because the boronic ester bonding, on the one hand, well associated the two kinds of polymer chains, and on the other hand, played the role of 'sacrificial crosslinks'. Furthermore, the occurrence of dynamic boronic ester bonding gave the hydrogel strain- and temperature-sensitive ionic conductivity, and therefore, the hydrogels could be used to identify human motions and as-resulted environmental temperature alterations, and worked well in various scenarios. This work activates new application of CMK in the multimodal sensing field, and also proposes an intriguing way of building multiple crosslinks in the KGM derivative-based hydrogels.

Improving the gel properties of Ficus pumila Linn. pectin by incorporating deacetylated konjac glucomannan

To improve the gelation behaviour of pectin, the effect of deacetylated konjac glucomannan (DKGM) with various deacetylation degrees (27.44 %, 44.32 %, 60.25 %, and 71.77 %) on the heat-induced gel characteristics of Ficus pumila Linn. pectin was studied. The hardness, chewiness, and adhesiveness of the gel increased as the degree of deacetylation increased from 27.44 % to 60.25 %, but decreased at 71.77 %. Additionally, DKGM addition resulted in higher apparent viscosity and non-Newtonian fluid behaviour in the composite gel. The incorporation of DKGM into the gel matrix strengthened the gel structure by promoting hydrogen bond formation and shortening relaxation time compared to the control. Scanning electron microscopy images revealed that the densification of the pectin gel network increased as the degree of deacetylation of konjac glucomannan rose from 27.44 % to 60.25 %, but then loosened when it exceeded 71.77 %. As the degree of deacetylation increased, the hydrophobic interaction between pectin and DKGM increased. Overall, the addition of DKGM effectively modulated the gel properties of Ficus pumila Linn. pectin, thus broadening its industrial application on different gel products.

Glucomannan isolation from porang (Amorphophallus muelleri Blume) flour using natural deep eutectic solvents and ethanol: A comparative study

Ethanol is a common solvent to isolate glucomannan from porang (Amorphophallus muelleri Blume) flour (NPF). This study investigated the use of natural deep eutectic solvents (NADESs) in glucomannan isolation from NPF. NADESs formed by the hydrogen bond acceptors (choline chloride and betaine) and the hydrogen bond donors (glycerol, 1,2-propanediol, formic acid, and acetic acid) in varying molar ratios of 1:2, 1:3, and 1:4 were characterized to optimize glucomannan isolation. The results showed that higher molar ratios of NADES tended to yield porang glucomannan flour (PGF) with higher glucomannan content and viscosity. The gel of PGF exhibited pseudoplastic behavior. The FTIR spectra indicated that betaine-based NADES removed the acetyl groups from glucomannan chains. The PGF obtained from NADESs with a molar ratio of 1:4 was comparable to those obtained from ethanol with a glucomannan content of 87.34 %-93.28 % and a weight-average molecular weight of 9.12 × 105-1.20 × 106 g/mol.

Effects of konjac glucomannan with different degrees of deacetylation on the properties and structure of wheat gluten protein

The properties and structure of gluten protein with different deacetylation degrees of konjac glucomannan (KGM) were investigated, in an attempt to improve the quality of gluten protein in flour products. Results showed that deacetylated KGM (DKGM) could improve the textural properties and enhance the thermal stability of gluten protein. DKGM increased the water holding capacity and shortened the T2 relaxation time of gluten after removing some acetyl groups. As the deacetylation degree increased, the hardness and adhesiveness of gluten gels gradually increased, while the springiness decreased. In addition, the presence of DKGM promoted the conversion from free sulfhydryl to disulfide bonds and increased the β-sheet content in gluten protein. The low-deacetylation KGM decreased the surface hydrophobicity and fluorescence intensity of gluten protein, and the microstructures of gluten gels became more compact. Compared with gluten protein-KGM complex gel, the degradation temperature of gluten protein-DKGM complex gels was observed to increase by >3 °C. Overall, the low-deacetylation KGM was beneficial for improving the physicochemical properties and maintaining the network structure of gluten protein. This study provides valuable references and practical insights to improve gluten quality in the flour industry.

Applications of polysaccharides in enzyme-triggered oral colon-specific drug delivery systems: A review

Enzyme-triggered oral colon-specific drug delivery system (EtOCDDS1) can withstand the harsh stomach and small intestine environments, releasing encapsulated drugs selectively in the colon in response to colonic microflora, exerting local or systematic therapeutic effects. EtOCDDS boasts high colon targetability, enhanced drug bioavailability, and reduced systemic side effects. Polysaccharides are extensively used in enzyme-triggered oral colon-specific drug delivery systems, and its colon targetability has been widely confirmed, as their properties meet the demand of EtOCDDS. Polysaccharides, known for their high safety and excellent biocompatibility, feature modifiable structures. Some remain undigested in the stomach and small intestine, whether in their natural state or after modifications, and are exclusively broken down by colon-resident microbiota. Such characteristics make them ideal materials for EtOCDDS. This article reviews the design principles of EtOCDDS as well as commonly used polysaccharides and their characteristics, modifications, applications and specific mechanism for colon targeting. The article concludes by summarizing the limitations and potential of ETOCDDS to stimulate the development of innovative design approaches.

Physicochemical and Rheological Properties of Degraded Konjac Gum by Abalone (Haliotis discus hannai) Viscera Enzyme

In the present study, a new degraded konjac glucomannan (DKGM) was prepared using a crude enzyme from abalone (Haliotis discus hannai) viscera, and its physicochemical properties were investigated. After enzymatic hydrolysis, the viscosity of KGM obviously decreased from 15,500 mPa·s to 398 mPa·s. The rheological properties analysis of KGM and DKGMs revealed that they were pseudoplastic fluids, and pseudoplasticity, viscoelasticity, melting temperature, and gelling temperature significantly decreased after enzymatic hydrolysis, especially for KGM-180 and KGM-240. In addition, the molecular weight of KGM decreased from 1.80 × 106 Da, to 0.45 × 106 Da and the polydispersity index increased from 1.17 to 1.83 after 240 min of degradation time. Compared with natural KGM, the smaller particle size distribution of DKGM further suggests enzyme hydrolysis reduces the aggregation of molecular chains with low molecular weight. FT-IR and FESEM analyses showed that the fragmented KMG chain did not affect the structural characteristics of molecular monomers; however, the dense three-dimensional network microstructure formed by intermolecular interaction changed to fragment microstructure after enzyme hydrolysis. These results revealed that the viscosity and rheological properties of KGM could be controlled and effectively changed using crude enzymes from abalone viscera. This work provides theoretical guidance for the promising application of DKGM in the food industry.

Konjac glucomannan-fibrin composite hydrogel as a model for ideal scaffolds for cell-culture meat

In this study, composite gel was prepared from konjac glucomannan (KGM) and fibrin (FN). Composite gels with different concentration ratios were compared in terms of their mechanical properties, rheological properties, water retention, degradation rate, microstructure and biocompatibility. The results showed that the composite gels had better gel strength and other properties than non-composite gels. In particular, composite hydrogels with low Young's modulus formed when the KGM concentration was 0.8% and the FN concentration was 1.2%. The two components were cross linked through hydrogen-bond interaction, which formed a more stable gel structure with excellent water retention and in-vitro degradation rates, which were conducive to myogenic differentiation of ectomesenchymal stem cells (EMSCs). KGM-FN composite gel was applied to the preparation of cell-culture meat, which had similar texture properties and main nutrients to animal meat as well as higher content of dry base protein and dry base carbohydrate.

Functional validation of AaCaM3 response to high temperature stress in Amorphophallus albus

Amorphophallus is a perennial monocotyledonous herbaceous plant native to the southwestern region of China, widely used in various fields such as food processing, biomedicine and chemical agriculture. However, Amorphophallus is a typical thermolabile plant, and the continuous high temperature in summer have seriously affected the growth, development and economic yield of Amorphophallus in recent years. Calmodulin (CaM), a Ca2+ sensor ubiquitous in eukaryotes, is the most important multifunctional receptor protein in plant cells, which affects plant stress resistance by participating in the activities of a variety of signaling molecules. In this study, the key gene AaCaM3 for the Ca2+-CaM regulatory pathway was obtained from A. albus, the sequence analysis confirmed that it is a typical calmodulin. The qRT-PCR results demonstrated that with the passage of heat treatment time, the expression of AaCaM3 was significantly upregulated in A. albus leaves. Subcellular localization analysis revealed that AaCaM3 localized on the cytoplasm and nucleus. Meanwhile, heterologous transformation experiments have shown that AaCaM3 can significantly improve the heat tolerance of Arabidopsis under heat stress. The promoter region of AaCaM3 was sequenced 1,338 bp by FPNI-PCR and GUS staining assay showed that the promoter of AaCaM3 was a high-temperature inducible promoter. Yeast one-hybrid analysis and Luciferase activity reporting system analysis showed that the AaCaM3 promoter may interact with AaHSFA1, AaHSFA2c, AaHSP70, AaDREB2a and AaDREB2b. In conclusion, this study provides new ideas for further improving the signal transduction network of high-temperature stress in Amorphophallus.

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.

Diversely regio-oxidative degradation of konjac glucomannan by lytic polysaccharide monooxygenase AA10 and generating antibacterial hydrolysate

Konjac glucomannan (KGM) hydrolysate exhibit various biological activities and health-promoting effects. Lytic polysaccharide monooxygenases (LPMOs) play an important role on enzymatic degradation of recalcitrant polysaccharides to obtain fermentable sugars. It is generally accepted that LPMOs exhibits high substrate specificity and oxidation regioselectivity. Here, a bacteria-derived SmAA10A, with chitin-active with strict C1 oxidation, was used to catalyse KGM degradation. Through ethanol precipitation, two hydrolysed KGM components (4 kDa (KGM-1) and 5 kDa (KGM-2)) were obtained that exhibited antibacterial activity against Staphylococcus aureus. In natural KGM, KGM-1, and KGM-2, the molar ratios of mannose to glucose were 1:2.19, 1:3.05, and 1:2.87, respectively, indicating that SmAA10A preferentially degrades mannose in KGM. Fourier-transform infrared spectroscopy and scanning electron microscopy imaging revealed the breakage of glycosylic bonds during enzymatic catalysis. The regioselectivity of SmAA10A for KGM degradation was determined based on the fragmentation behaviour of the KGM-1 and KGM-2 oligosaccharides and their NaBD4-reduced forms. SmAA10A exhibited diverse oxidation degradation of KGM and generated single C1-, single C4-, and C1/C4-double oxidised oligosaccharide forms. This study provides an alternative method for obtaining KGM degradation components with antibacterial functions and expands the substrate specificity and oxidation regioselectivity of bacterial LPMOs.

Maternal supplementation with konjac glucomannan improves maternal microbiota for healthier offspring during lactation

BACKGROUND

The maternal diet during gestation and lactation affects the health of the offspring. Konjac glucomannan (KGM) is a significantly functional polysaccharide in food research, possessing both antioxidant and prebiotic properties. However, the mechanisms of how KGM regulates maternal nutrition remain insufficient and limited. This study aimed to investigate maternal supplementation with KGM during late gestation and lactation to benefit both maternal and offspring generations.

RESULTS

Our findings indicate that KGM improves serum low density lipoprotein cholesterol (LDL-C) and antioxidant capacity. Furthermore, the KGM group displayed a significant increase in the feed intake-related hormones neuropeptide tyrosine (NPY), Ghrelin, and adenosine monophosphate-activated kinase (AMPK) levels. KGM modified the relative abundance of Clostridium, Candidatus Saccharimonas, unclassified Firmicutes, and unclassified Christensenellaceae in sow feces. Acetate, valerate, and isobutyrate were also improved in the feces of sows in the KGM group. These are potential target bacterial genera that may modulate the host's health. Furthermore, Spearman's correlation analysis unveiled significant correlations between the altered bacteria genus and feed intake-related hormones. More importantly, KGM reduced interleukin-6 (IL-6) levels in milk, further improved IL-10 levels, and reduced zonulin levels in the serum of offspring.

CONCLUSION

In conclusion, maternal dietary supplementation with KGM during late gestation and lactation improves maternal nutritional status by modifying maternal microbial and increasing lactation feed intake, which benefits the anti-inflammatory capacity of the offspring serum. © 2024 Society of Chemical Industry.

Natural self-healing injectable hydrogels loaded with exosomes and berberine for infected wound healing

Complete and rapid healing of infected skin wounds remains a challenge in current clinical treatment. In this study, we prepared a self-healing injectable CK hydrogel by crosslinking two natural polysaccharides, carboxymethyl chitosan and oxidized konjac glucomannan, based on the Schiff base bond. To enhance the biological function of the hydrogel, we multi-functionalized hydrogen by loading it with berberine (BBR) and stem cell-derived exosomes (Exo), forming a composite hydrogel, CK@BBR&Exo, which could be injected directly into the wound through a needle and adhered to the wound. Furthermore, the self-healing properties of CK@BBR&Exo increased its usefulness and service life. Additionally, the drug-loaded CK@BBR&Exo hydrogel was versatile, inhibiting bacterial growth, regulating the inflammatory response, and promoting neovascularization in infected skin wounds, thus achieving the rapid healing of infected skin wounds. These results suggest that the CK@BBR&Exo-injectable self-healing hydrogel is an ideal dressing for treating infected skin wounds.

Improvement of kefir fermentation on rheological and microstructural properties of soy protein isolate gels

Soy protein isolate (SPI) has become a promising plant-based material as an animal protein products alternative. However, its application was limited due to the weak gelling properties. To investigate the effect of kefir fermentation on SPI gels properties, SPI-polysaccharide gels was produced by unfermented and kefir-fermented SPI using different concentration of KGM, chitosan, and calcium chloride in this study. Characterization of fermented SPI gels showed that fermentation by kefir grains can be applied to improve the textural strength, mechanical structure, and thermal characteristics of SPI gels. Compared to unfermented SPI gels, the water-holding capacity was remarkably enhanced to 63.11% and 65.71% in fermented SPI-chitosan gels. Moreover, the hardness of fermented SPI-KGM gels were significantly increased to 13.43 g and 27.11 g. And the cohesiveness and resilience of fermented-KGM gels were also improved than unfermented samples. Results of rheological characterization and thermogravimetric analysis revealed the strengthened mechanical features and higher thermal stability of fermented SPI gels. Additionally, the main role of hydrophobic interactions and secondary structure variations of SPI gels were demonstrated by intermolecular force measurements, Fourier-transform infrared spectroscopy, and X-ray diffraction. Moreover, the network structure was observed more compact and homogeneous performed by microstructural images in fermented SPI gels. Therefore, this research provided a novel approach combining multi-species fermentation with protein gelation to prepare SPI gel materials with improved nutrition and structural properties.

Konjac glucomannan promoted fabrication of diacylglycerol oil-based oleogels through emulsion-templated approach: Comparison with triacylglycerol oleogels

Konjac glucomannan (KGM) combined with hydroxypropyl methyl cellulose was used to fabricate diacylglycerol oleogels (DGOs) through the emulsion-templated method, and compared with triacylglycerol oleogels (TGOs). The appearance and microstructure results showed that stable emulsions and oleogels could be formed in the presence of 0.2-0.6 wt% KGM. Higher KGM concentrations resulted in a stronger gel structure in oleogels, whose thixotropic recovery percentages were 50.45-75.20 %. From LF-NMR determination, the higher concentration of KGM presented earlier transverse relaxation (T2) time, and the T2 parameters of DGOs were higher than that of TGOs. Texture and oil loss analysis indicated that the mechanical strength and oil holding ability of DGOs were slightly lower than those of TGOs. This study demonstrated the advantages of biopolymers as thickening agents for obtaining stable emulsion and oleogels. The specific characteristics of DGOs distinguished from TGOs should be attributed to their different properties (unsaturation, viscosity, polarity, etc.) between the liquid oils.

Influence of konjac glucomannan and its derivatives on the oral pharmacokinetics of antimicrobial agent in antibiotics cocktails: Keep vigilant on dietary fiber supplement

In this study, konjac glucomannan (KGM) and its derivatives were gavaged as dietary fiber supplements, followed by a single dose of antibiotic cocktail (Abx) containing amoxicillin, neomycin, metronidazole and vancomycin in mice. The effects of dietary fiber on the pharmacokinetics and tissue distribution of each antibiotic were investigated. The results showed that the specific effects of KGM and its derivatives on the absorption, distribution, and elimination of certain antibiotics varied and depended on the nature of the fibers and the characteristics of the antibiotics. Explicitly, the ingestion of KGM and its derivatives enhanced the absorption of metronidazole by 1.7 times and hindered that of amoxicillin by nearly 36 % without affecting the absorption of neomycin sulfate and vancomycin. KGM and its derivatives had no effect on the distribution of amoxicillin and metronidazole, but DKGM and KGM hindered the distributions of neomycin sulfate (from 1.25 h to 1.62 h) and vancomycin (from 0.95 h to 1.14 h), respectively. KGM and its derivatives promoted the elimination of amoxicillin by nearly 38 % while prolonging that of metronidazole by >50 %. KOGM boosted the elimination of neomycin sulfate and vancomycin, but KGM differed from DKGM in acting on the elimination of both.

Identification and Characterization of a Novel Mannanase from Klebsiella grimontii

Konjac glucomannan (KGM) is a natural polysaccharide derived from konjac, which has been widely used in various fields due to its numerous beneficial properties. However, the high viscosity and water absorption of KGM limit its application. Compared with KGM, Konjac glucomannan oligosaccharides (KGMOS) have higher water solubility and stronger application value. In this paper, a novel mannanase KgManA was cloned from Klebsiella grimontii to develop a new KGMOS-producing enzyme. Bioinformatic analysis shows that the structural similarity between KgManA and other enzymes was less than 18.33%. Phylogenetic analysis shows that KgManA shares different branches with the traditional mannanases containing the CMB35 domain, indicating that it is a novel mannanase. Then, the enzymatic properties were determined and substrate specificity was characterized. Surprisingly, KgManA is stable in a very wide pH range of 3.0 to 10.0; it has a special substrate specificity and seems to be active only for mannans without galactose in the side chain. Additionally, the three-dimensional structure of the enzyme was simulated and molecular docking of the mannotetraose substrate was performed. As far as we know, this is the first report to characterize the enzymatic properties and to simulate the structure of mannanase from K. grimontii. This work will contribute to the development and characterization of novel K. grimontii-derived mannanases. The above results indicate that KgManA is a promising tool for the production of KGMOS.

Konjac glucomannan-assisted curcumin alleviated dextran sulfate sodium-induced mice colitis via regulating immune response and maintaining intestinal barrier integrity

Curcumin has been proven to be an effective strategy for reducing inflammatory responses. However, low bioavailability and instability at the physiological pH have limited its anti-inflammatory activity in ulcerative colitis patients. In the present study, a complex of curcumin and konjac glucomannan (KGM) effectively inhibited intestinal inflammation and this effect was associated with KGM degradation degrees. Results demonstrated that treatment with the complex markedly mitigated colitis symptoms and decreased inflammatory cytokines levels, especially in the complex treatment groups with K110 (KGM treated in 110 °C) and konjac oligosaccharides (KOSs). Furthermore, increasing the KOS content in KOC (the complex of curcumin and KOS) promoted the gene expressions of the intestinal barrier and inhibited the gene expressions of inflammatory cytokines, as well as improved gut microbiota dysregulation. Overall, our studies suggest that the complex of curcumin and KGM exerts effective anti-inflammatory effects by regulating the intestinal immune response and modulating microbiota diversity and composition.

Synergistic effects of oxidized konjac glucomannan on rheological, thermal and structural properties of gluten protein

Oxidation is an effective way to prepare depolymerized konjac glucomannan (KGM). The oxidized KGM (OKGM) differed from native KGM in physicochemical properties due to different molecular structure. In this study, the effects of OKGM on the properties of gluten protein were investigated and compared with native KGM (NKGM) and enzymatic hydrolysis KGM (EKGM). Results showed that the OKGM with a low molecular weight and viscosity could improve rheological properties and enhance thermal stability. Compared to native gluten protein (NGP), OKGM stabilized the protein secondary structure by increasing the contents of β-sheet and α-helix, and improved the tertiary structure through increasing the disulfide bonds. The compact holes with shrunk pore size confirmed a stronger interaction between OKGM and gluten protein through scanning electron microscopy, forming a highly networked gluten structure. Furthermore, OKGM depolymerized by the moderate ozone-microwave treatment of 40 min had a higher effect on gluten proteins than that by the 100 min treatment, demonstrating that the excessive degradation of KGM weakened the interaction between the gluten protein and OKGM. These findings demonstrated that incorporating moderately oxidized KGM into gluten protein was an effective strategy to improve the properties of gluten protein.

Tailoring Food Biopolymers into Biogels for Regenerative Wound Healing and Versatile Skin Bioelectronics

An increasing utilization of wound-related therapeutic materials and skin bioelectronics urges the development of multifunctional biogels for personal therapy and health management. Nevertheless, conventional dressings and skin bioelectronics with single function, mechanical mismatches, and impracticality severely limit their widespread applications in clinical. Herein, we explore a gelling mechanism, fabrication method, and functionalization for broadly applicable food biopolymers-based biogels that unite the challenging needs of elastic yet injectable wound dressing and skin bioelectronics in a single system. We combine our biogels with functional nanomaterials, such as cuttlefish ink nanoparticles and silver nanowires, to endow the biogels with reactive oxygen species scavenging capacity and electrical conductivity, and finally realized the improvement in diabetic wound microenvironment and the monitoring of electrophysiological signals on skin. This line of research work sheds light on preparing food biopolymers-based biogels with multifunctional integration of wound treatment and smart medical treatment.

Review of Konjac Glucomannan Structure, Properties, Gelation Mechanism, and Application in Medical Biology

Konjac glucomannan (KGM) is a naturally occurring macromolecular polysaccharide that exhibits remarkable film-forming and gel-forming properties, and a high degree of biocompatibility and biodegradability. The helical structure of KGM is maintained by the acetyl group, which plays a crucial role in preserving its structural integrity. Various degradation methods, including the topological structure, can enhance the stability of KGM and improve its biological activity. Recent research has focused on modifying KGM to enhance its properties, utilizing multi-scale simulation, mechanical experiments, and biosensor research. This review presents a comprehensive overview of the structure and properties of KGM, recent advancements in non-alkali thermally irreversible gel research, and its applications in biomedical materials and related areas of research. Additionally, this review outlines prospects for future KGM research, providing valuable research ideas for follow-up experiments.

Effect of konjac oligo-glucomannan on emulsifying properties of myofibrillar protein

BACKGROUND

The high viscosity of konjac glumannan (KGM) limits its application in meat processing. In this work, the effects of konjac oligo-glucomannan (KOG), as a derivative of KGM, on the emulsifying properties of myofibrillar protein (MP) and the related mechanism were investigated.

RESULTS

It was found that the addition of KOG had no significant effect on the secondary structure of MP, but altered the tertiary conformation of MP, resulting in exposure of tyrosine residues to polar microenvironments and decreased intrinsic fluorescence intensity. In addition, the addition of KOG increased the emulsifying activity of MP, resulting in decreased particle size and improved physical stability of the emulsion. The emulsifying activity of MP reached the maximum value when 1.0 wt% KOG was added. Moreover, the interfacial tension and interfacially adsorbed protein content of MP/KOG emulsions decreased with the increase in KOG concentration.

CONCLUSION

These findings demonstrated that KOG mainly interacted with MP and changed the amphipathy of the KOG-MP at the oil-water interface, forming a stable interface film to improve the emulsifying properties of MP. © 2023 Society of Chemical Industry.

Effects of Physical Properties of Konjac Glucomannan on Appetite Response of Rats

Dietary fiber has been widely used in designing foods with a high satiating capacity, as the use of satiety-enhancing food is considered to be a promising strategy for combating obesity and the overweight condition. In the present study, partially degraded konjac glucomannan (DKGM) diets with different water-holding capacities, swelling capacities, and viscosities were used to feed rats to investigate the effects of the fiber's physical properties in regulating the appetite response of the animals. The results showed that the mass and water content of the gastrointestinal chyme increased as the diet's physical properties were enhanced by the DKGM, which increased the stomach distention of the rats and promoted satiation. Besides, the hydrated DKGM elevated the chyme's viscosity, and the retention time of the digesta in the small intestine was prolonged significantly, which resulted in an increased concentration of cholecystokinin-8, glucagon-like peptide 1, and peptide tyrosine-tyrosine in the plasma, thus helping to maintain the satiety of rats. Furthermore, the results of the behavioral satiety sequence and meal pattern analysis showed that DKGM in the diets is more likely to reduce the food intake of rats by enhancing satiety rather than satiation, and will finally inhibit excessive weight gain. In conclusion, the physical properties of dietary fiber are highly related to the appetite response, which is a powerful tool in designing food with a high satiating capacity.

Effects of Combining High Pressure Processing Treatments and Konjac Glucomannan and Sodium Caseinate on Gel Properties of Myosin Protein

Effects of two high pressure processing treatments and various levels of konjac glucomannan (KGM) and sodium caseinate (SC) on texture properties, water-holding capacity, and ultra-structure of gels of rabbit myosin protein were investigated. The two high pressure processing treatments were as follows: (1) mean pressure (200 MPa), low temperature (37 °C), and holding for a short time (5 min) followed heating (80 °C for 40 min) (gel LP + H), and (2) high pressure (500 MPa), high temperature (60 °C), and holding for a long time (30 min) (gel HP). Gel LP + H have better gel properties (increased hardness, springiness, gumminess, adhesiveness, cohesiveness, and water binding capacity) than gels HP. Above all, gels myosin + SC:KGM (2:1) have best gel properties. KGM and SC both significantly improved the gel texture properties and water binding capacity.

Konjac Glucomannan: An Emerging Specialty Medical Food to Aid in the Treatment of Type 2 Diabetes Mellitus

There are many factors causing T2DM; thus, it is difficult to prevent and cure it with conventional treatment. In order to realize the continuous intervention of T2DM, the treatment strategy of combining diet therapy and traditional medication came into being. As a natural product with the concept of being healthy, konjac flour and its derivatives are popular with the public. Its main component, Konjac glucomannan (KGM), can not only be applied as a food additive, which greatly improves the taste and flavor of food and extends the shelf life of food but also occupies an important role in T2DM. KGM can extend gastric emptying time, increase satiety, and promote liver glycogen synthesis, and also has the potential to improve intestinal flora and the metabolic system through a variety of molecular pathways in order to positively regulate oxidative stress and immune inflammation, and protect the liver and kidneys. In order to establish the theoretical justification for the adjunctive treatment of T2DM, we have outlined the physicochemical features of KGM in this article, emphasizing the advantages of KGM as a meal for special medical purposes of T2DM.

Thermal and Rheological Performances Evaluation of a Modified Biopolymer for Fracturing Fluid System

Developing an efficient fracturing fluid system is an enduring hot topic in the petrochemical industries, especially regarding the exploitation of limited oil. Biopolymers, especially polysaccharides (e.g., konjac gum, guar gum), are widely applied as fracturing fluids in fracturing as a result of their advantages. Herein, we propose an easy method of modifying konjac gum (KGM) using isopropanol, sodium hydroxide, and chloroacetic acid to obtain modified konjac glum (MKGM). The MKGM and KGM gels were also obtained by using the self-prepared organic titanium high-temperature stabilizer and organic borate cross-linker. The prepared MKGM was characterized by multiscale techniques, including attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and rheology properties. The ATR-FTIR results showed that the etherification modification reaction occurred as designed. The XRD results showed that the regularity of KGM was destroyed after modification. The TGA and DSC results showed that the thermal stability improved. Rheology measurements illustrated that the temperature and shear resistance of MKGM were better than those of KGM. The MKGM gel could be applied in fracturing fluid systems at a lower frequency through viscoelastic measurements.

Gelation of konjac glucomannan by acetylmannan esterases from Aspergillus oryzae

Konjac glucomannan (KGM) is a principal component of the gelatinous food Konjac. Konjac production through alkali treatment releases an undesirable amine-odor. Two acetylesterases (AME1 and AME2) active against konjac glucomannan (polymer or oligomer) were purified from the supernatant of Aspergillus oryzae RIB40 culture. We cloned the genes encoding AME1 and AME2 based on the genomic information of A. oryzae, constructed their expression systems in A. oryzae, and obtained the recombinant enzymes (rAME1 and rAME2). rAME1 did not act on the KGM polymer but only on the KGM oligomer, releasing approximately 60% of the acetic acid in the substrate. However, rAME2 was active against both KGM substrates, releasing approximately 80% and 100% of acetic acid from the polymer and oligomer, respectively. Both enzymes were active against xylan and exhibited a trace activity on ethyl ferulate. The acetyl group position specificities of both enzymes were analyzed via heteronuclear single quantum correlation NMR using oligosaccharides of glucomannan prepared from Aloe vera (AGM), which has a higher acetyl group content than KGM. rAME1 acted specifically on single-substituted acetyl groups and not on double-substituted ones. In contrast, rAME2 appeared to act on all the acetyl groups in AGM. Treatment of 3% KGM with rAME2 followed by heating to 90 °C resulted in gel formation under weakly acidic conditions. This is the first study to induce gelation of KGM under these conditions. A comparison of the breaking and brittleness properties of gels formed by alkaline and enzymatic treatments revealed similar texture of the two gels. Furthermore, scanning electron microscopy of the surface structure of both gels revealed that both formed a fine mesh structure. Our findings on enzymatic gelation of KGM should lead to the development of new applications in food manufacturing industry.