Deacetylated Konjac Glucomannan Research Articles

Use of ozone oxidation in combination with deacetylation for improving the structure and gelation properties of konjac glucomannan

In this study, oxidized deacetylated konjac glucomannans with different degrees of oxidation were prepared by a combination of deacetylation and ozone oxidation. Carboxyl groups were found to be introduced into the modified konjac glucomannan while acetyl groups were removed. The backbone, branched chains, and crystal structure of modified konjac glucomannan were not significantly affected. The whiteness was enhanced to 97–99 % and the thermal degradation temperature was up to 250 °C after modification. The solubility of the modified konjac glucomannan (oxidized for 60 min) was significantly increased to 84.56 % (p < 0.05), while its viscosity and swelling power were notably decreased owing to the changes in molecular weight (from 106 to 104) and functional groups. Rheological analysis showed that oxidized deacetylated konjac glucomannan has the ability to form soft-textured gels and the potential to develop dysphagia foods. Future studies should focus on the gelation mechanisms of oxidized deacetylated konjac glucomannan.

A comparative study of molecular structure, rheology, and thermal characteristics of deacetylated konjac glucomannan-treated gluten during frozen storage

Konjac glucomannan is extensively employed to enhance the quality of wheat-based products. Despite this, the utilization of natural KGM in the food industry is restricted due to its inadequate mechanical attributes, heightened susceptibility to humidity, and unappealing taste profile. In this study, the influence of deacetylated konjac glucomannan (DKGM) on the structure, rheology, and thermal characteristics of gluten during frozen storage was explored. Furthermore, the mechanism outlining the action between gluten and DKGM was analyzed. The secondary structure results showed that DKGM promoted the formation of α-helices and β-sheets in gluten. Scanning electron microscopy analysis confirmed that DKGM made the gluten network more stable. Moreover, DKGM provided a significant improvement in the rheological and thermal properties of frozen gluten. This is attributes to the fact that DKGM alters the hydrophobic residues in frozen gluten. Overall, this work indicates that the molecular structure and thermal properties of gluten are optimally substantial improvements at a substitution content of 1.5% D3 (deacetylation degree of 95%) in the dough. These findings provide a reference value for the application of DKGM in frozen wheat-based foods.

Effects of deacetylated konjac glucomannan on the quality characteristics, staling and digestion of Chinese steamed bread

This study aimed to explore the effect of deacetylated konjac glucomannan (DKGM) on the quality characteristics, staling, and digestive properties of Chinese steamed bread (CSB). The findings revealed that the addition of DKGM led to a larger specific volume, a lighter and more yellowish crumb color, and a softer texture of the CSB. Notably, 0.6% DKGM with a deacetylation degree (DD) of 50.26% integrated with the gluten network resulted in a more stable gluten structure in the dough and a 5.74% increase in the CSB specific volume, reaching 3.13 mL/g. Moreover, higher deacetylation of KGM (DD = 66.61%) significantly delayed CSB aging, as evidenced by factors such as freezable water content, staling rate, and starch crystallinity. High deacetylation of KGM exhibited the optimum digestive resistance of CSB. 1% KGM with high DD (DD = 66.61%) led to a 10.21% decrease in the rapidly digested starch content and a 3.98% decrease in the starch hydrolysis rate compared with the KGM, which might be attributed to highly deacetylated KGM may form stronger hydrogen bonds with starch. This study offered insights into the application of DKGM in advancing the industrialization of CSB.

Deacetylated Konjac Glucomannan with a Slower Hydration Rate Delays Rice Digestion and Weakens Appetite Response.

The physical characteristics of chyme during gastrointestinal digestion are considered to significantly affect nutrient digestion and absorption (such as glucose diffusion), which has an impact on postprandial satiety. The present study aims to analyze the hydration rate (HR) and rheological properties of deacetylated konjac glucomannan (DKGM) at different degrees and then explore their effects on rice texture, digestive properties, and the subjects' post-meal appetite. The present results show that, as the deacetylation degree (DD) of KGM increased, the intersection point of the viscoelastic modulus shifted to a high shear rate frequency, and as the swelling time of the DKGM was prolonged, its HR decreased significantly. The results of the in vitro gastrointestinal digestion tests show that the hardness and chewability of the rice in the fast-hydration group (MK1) were remarkably reduced. In contrast, the slow-hydration group (MK5) exhibited an outstanding ability to resist digestion. The kinetics of starch hydrolysis revealed that the HR of the rice in the fast-hydration group was 1.8 times faster than that of the slow-hydration group. Moreover, it was found that the subjects' appetite after the meal was highly related to the HR of the MK. Their hunger (p < 0.001), desire to eat (p < 0.001), and prospective food consumption (p < 0.001) were significantly inhibited in the slow-hydration group (MK5) compared to the control. This study explored the nutritional effects of the hydration properties derived from the DKGM, which may contribute to modifying the high glycemic index food and provide ideas for the fabrication of food with enhanced satiating capacity.

Moisture, rheology and structure of deacetylated konjac glucomannan-treated dough and the performance of steamed bread under frozen storage

Deacetylated konjac glucomannan (Da) is utilized to enhance the quality of wheat products. This study investigated the impact of Da1, Da2 and Da3 (with deacetylation degrees of 23.62, 59.60 and 95.53%, respectively) as well as frozen storage times on the moisture, rheological and structural characteristics of dough, as well as the quality of the resulting steamed bread. The findings indicated that Da played a significant role in improving the freezable water content, moisture distribution and rheology of the dough. Especially, in the 1.5% Da2 group, the improvement effect on dough was most significant and the gluten network structure was the most compact. Moreover, Da exerted a positive influence on the quality of the steamed bread with 1.5% Da2 showing the most significant improvements. Correlation analysis revealed a negative relationship between the dough's freezable water content and its rheological properties, bound water content and disulfide bonds. These findings provide a theoretical foundation for the industrial application of Da in wheat-based products.

Development and evaluation of deacetylated konjac glucomannan based films incorporated with cellulose nanofibers and alumina nanoparticles

Development and evaluation of deacetylated konjac glucomannan based films incorporated with cellulose nanofibers and alumina nanoparticles

Effect of deacetylated konjac glucomannan on the 3D printing properties of minced pork.

The influences of deacetylated konjac glucomannan (DKGM) at different condition levels (0.0%, 0.5%, 1.0%, 1.5%, 2.0%) on the 3D printing feasibility, printing properties, and the final gel characteristics of minced pork were investigated. As the DKGM content increased, the printing accuracy and stability initially increased and then declined, and the printing stability and accuracy increased to their highest levels (98.16% and 98.85%) with a 1.5% addition of DKGM. Furthermore, the addition of DKGM significantly enhanced the texture of 3D-printed meat after heat treatments. When the DKGM content reached 1.5%, the hardness and springiness were 1.19 and 1.06 times higher than those of the control group. The results of low-field nuclear magnetic resonance and Raman spectra revealed that DKGM enhanced the amount of bound water in 3D-printed meat and encouraged changes in protein structure. After the addition of DKGM at 1.5%, the contents of bound water and β-sheets were 7.67% and 12.89% higher than those of the control group, respectively, facilitating the development of a better gel network of minced meat during heating. The results indicate that a concentration of 1.5% DKGM is the ideal setting for obtaining the desired rheological properties and textural characteristics (printability) of 3D-printed minced meat products compared to other samples. In addition, the results showed that the addition of DKGM at 1.5% promotes the transition from α-helix to β-folding of proteins during heating, which facilitates the formation of gels. The results of the study contribute to the application potential of minced meat in the field of 3D food printing. © 2024 Society of Chemical Industry.

Heat-induced gel formation by whey protein isolate-deacetylated konjac glucomannan at varying pH conditions

This study explored the formation of composite gels via pH-modulated whey protein isolate (WPI) and deacetylated konjac glucomannan (KGM) solutions. The physicochemical properties, gelation characteristics, and microstructure of WPI-KGM gels were evaluated at varied pH levels (2−10). Findings revealed that WPI and deacetylated KGM failed to generate a stable gel at pH extremes (2 or 10). However, under optimal pH conditions (4 or 8), the WPI-KGM system yielded gels exhibiting superior water-holding capacity and hardness after heat treatment, with the composite gel at pH 4 demonstrating enhanced whiteness compared to that at pH 8. Textural and rheological assessments suggested that moderate pH levels favor the formation of well-structured gels. Scanning electron microscopy showed denser structures at pH 4 and 8, contrasting with disordered, coarse gel networks at pH 2 and 6. At pH 4, the WPI-KGM gel structure was primarily maintained by electrostatic and hydrophobic interactions, whereas at pH 8, disulfide bonds became pivotal. Overall, our findings underlined the importance of appropriate pH conditions in facilitating composite gel formation, offering practical insights for heat-induced gel material development in the food industry.

Developing concentrated emulsion gel hybrids structured by natural food fibres

The integration of healthy unsaturated fat into plant-based meat alternatives is being advocated worldwide but remains technically challenging, due to limitations in the textural qualities and processability of edible oil. One way to improve the rheological behaviour of oil is via emulsion gel technology. However, adaptable solutions for real-life food processing are few and far between. On this basis, we formulated physically stable emulsion gel hybrid templates with 50–83% sunflower oil load, mostly oil-in-water microstructure, and structured solely by natural food fibres without using oleogelators. The fibres included citrus fibre and soy polysaccharides as emulsifying fibres, and curdlan and deacetylated konjac glucomannan as structuring fibres. Upon heating, they developed stiffness up to 10E4 Pa in storage modulus G′. Here, we present the first characterisation of such fibre-based emulsion gel hybrids through analysis by epifluorescence microscopy, oscillatory rheology, and diffusing wave spectroscopy, and report underlying composition-structure-rheology-thermal behaviour relations. The key findings are that strength in the emulsion gel hybrid could come from combinations of the following observed mechanisms: (i) tiny droplets of dispersed phase droplets with high curvature, (ii) emulsifying fibre of high molecular weight, (iii) controlled interference from emulsifying fibre on the viscoelastic network development of structuring fibre, and (iv) for additional shear stability, highly aggregated state of dispersed phase droplets without coalescence. Promising templates bearing close resemblance to animal fat references such as pork belly fat (in terms of G′), and shear stability with potential toward extrusion and food printing application have been identified.

Effects of Deacetylated Konjac Glucomannan on the pasting, rheological and retrogradation properties of wheat starch

The heat intolerance and retrogradation behavior of native wheat starch (WS) are undesirable for starch-based gel foods, therefore the combinations of WS and hydrocolloids have attracted extensive attentions. The objectives of this study were to investigate the effects of konjac glucomannan (KGM) with different degree of deacetylation (DD) on the pasting, rheological and retrogradation properties of WS. Results showed that deacetyl-konjac glucomannan (DKGM) increased the peak viscosity (PV), trough viscosity (TV) and final viscosity (FV), while decreased the breakdown (BD) values of WS, suggesting the enhancement of the viscosity and thermal stability of WS paste. The raised storage modulus (G′) of WS gels with DKGM1 (DD, 48.23%) demonstrated that the partial removal of acetyl groups from KGM chains effectively promoted the formation of gel network, accompanied by increased elasticity. After storing at 4 °C for 7 days, the hardness of gels increased up 369%, while supplement with DKGM significantly (p < 0.05) decreased the hardness. These data demonstrated that DKGM delayed the process of starch retrogradation, which was further verified by LF-NMR analysis. Besides, the addition of DKGM reduced the retrogradation rate, relative crystallinity and the orderliness of WS-DKGM gels with the prolonging of storage at 4 °C, all validating the hindrance of starch retrogradation by DKGM. Therefore, these data suggested that partial deacetylation of KGM could effectively improve the pasting, rheological characteristics and impede the retrogradation of WS.

Carbohydrate supplementation retains intestinal barrier and ameliorates bacterial translocation in an antibiotic-induced mouse model.

Bacterial translocation (BT), with antibiotic use as an inducer, is associated with increased risk of developing multiple inflammatory disorders, and is closely associated with intestinal barrier integrity. Deacetylated konjac glucomannan (DKGM) and konjac oligo-glucomannan (KOGM) are two of the most widely used derivatives in the food industry. They are structurally and physiologically distinct from konjac glucomannan (KGM), and previous studies have confirmed their prebiotic effects. But whether they play a role in antibiotic-induced BT is unknown. Here, we applied an antibiotic cocktail (Abx) to a mouse model and investigated whether and how KGM and its derivatives function in BT and inflammation response amelioration during and after antibiotics, and which intervention plan is more effective. The results showed that KGM and its derivatives all inhibited BT. The colon tissue lesions caused by BT were largely alleviated, and short-chain fatty acid (SCFA) production was highly improved with the supplementation of carbohydrates. The prolonged intervention plan using KGM and its derivatives was more efficient than intervention only during the Abx administration period. Among the three dietary fibers, KGM behaved best, while DKGM and KOGM behaved equivalently. Additionally, KGM and its derivatives all reduced the inflammatory response accompanying BT, but DKGM may have a direct inhibitory efficacy in inflammation other than that through IL-10, unlike KGM or KOGM.

Thermo-irreversible emulsion gels based on deacetylated konjac glucomannan and methylcellulose as animal fat analogs

As animal-fat analogs, polysaccharide-emulsion gels with different ratio of methylcellulose (MC) to deacetylated konjac glucomannan (DKG) ratios (DKG:MC = 2:8–8:2) were prepared using two different oils (canola (Ca) and coconut oil (Co)). The emulsion gels (Ca-EG and Co-EG) were thermo-irreversible and thermo-stable at 80 °C, irrespective of the DKG:MC ratio, owing to the dominant thermo-gelling properties of MC. At 20 °C, the texture profiles and viscoelasticity were dependent on the DKG:MC ratio, which impact the molecular interactions (hydrogen bonds). The components of the emulsion gels exhibited a synergistic effect on gelation over a wide temperature range. The Co-EG exhibited enhanced gel strength and stability. The emulsion gels provided lower energy than pork back fat (p < 0.05) and higher stability against oxidation during refrigerated storage at 4 °C for 28 d. As a new fat analog system, this thermo-irreversible emulsion gel has potential utility in the plant-based food industry.

Preparation and characterization of deacetylated konjac glucomannan / pectin composite films crosslinked with calcium hydroxide

Preparation and characterization of deacetylated konjac glucomannan / pectin composite films crosslinked with calcium hydroxide

Structural complexity of Konjac glucomannan and its derivatives governs the diversity and outputs of gut microbiota

Deacetylated Konjac Glucomannan (DKGM) and Konjac Oligo-glucomannan (KOGM) as two most widely used derivatives in food industry are structurally and physiologically distinct from Konjac glucomannan (KGM). However, the roles of their distinct structures and physicochemical properties in directing microbiota community and the following outcomes are not fully understood. This paper aims to build links between structural complexity of KGM and its derivatives and microbial metabolism. Results showed that structural alterations changed molecular chain aggregation and water binding ability, thus affected the susceptibility to enzymatic degradation, leading to the distinct microbial composition and outcomes profile. Explicitly, KOGM was distinctive in higher abundances of Catenibacterium and Megasphaera, and lacking Prevotella, which was additionally enriched by KGM and DKGM. KOGM, owned the same butyrate-dominant profile with KGM, was utilized fast. However, KGM possessed the highest fermentability. Severe deacetylation reduced fermentability and led DKGM to a propionate-dominant pattern.

Gut microbiota plays a predominant role in affecting hypolipidemic effect of Deacetylated Konjac Glucomannan (Da-KGM)

The mechanism of Da-KGM showed poorer hypolipidemic effect, has not elucidated in previous study. Here, we performed hyperlipidemic hamsters administrated with 6% KGM (Konjac Glucomannan) and Da-KGM respectively to evaluate different underlying mechanisms. Poorer lipid-lowering effect was shown with Da-KGM treatment, and marked changes in relative abundance of Aldercreutzia and Parasutterella were not detected as KGM. Meanwhile, significant alteration of Ileibacterium was observed between KGM and Da-KGM group. Moreover, pathway of primary bile acids synthesis was enriched in cecal metabolites. KGM, not Da-KGM, remarkably increased concentration of Glycocholic acid (GCA) and Ursodeoxycholic acid (UDCA), which were negatively corrected with Ileibacterium. Marked increases in ileal Farnesoid X receptor (FXR) and hepatic Cholesterol 7α-hydroxylase (CYP7A1) were observed in KGM group, along with strong reduction of ileal Multi-drug resistance-associated protein2 (MRP2/ABCC2) and hepatic FXR expression, but not in Da-KGM group. There were no obvious changes in serum lipid level and bile acids, as well as gene expression after antibiotic treatment. Our results revealed that different hypolipidemic effects of KGM and Da-KGM might be associated with gut microbiota and bile acids metabolism.

Preparation and characterization of konjac glucomannan (KGM) and deacetylated KGM (Da-KGM) obtained by sonication.

Konjac glucomannan (KGM) has been widely applied in the food industry as a thickening and gelation agent because of its unique colloidal properties of viscosity enhancement and gelling ability. The current study aimed to prepare and characterize KGM and deacetylated KGM (Da-KGM) samples obtained by sonication in neutral and alkali ethanol-water solutions. The results showed that the deacetylation degree (DD) of Da-KGM increased exponentially with alkali concentration. Fourier transform infrared spectrometry further confirmed the deacetylation reaction through the dramatic decrease in the acetyl group band at 1740 cm-1 . Besides, the high similarity among the tested groups in terms of X-ray diffraction (XRD) spectra implied a similar crystalline structure, while differential scanning calorimetry (DSC) curves revealed that the water binding capacity and decomposition temperature of KGM changed slightly with alkali and sonication treatment. The rheological profiles indicated that apparent viscosity (η0 ) of sonicated KGM samples was unchanged except for the T60 group (60 min sonication treatment). Particularly, ultrasonic treatment under high alkaline conditions (0.10mol L-1 NaOH) was noted to promote the deacetylation reaction, and the obtained samples showed decreased apparent viscosity and weakened the gelation process in aqueous solution. Partial correction analysis indicated that alkali rather than ultrasonic treatment resulted in the change of DD and η0 in Da-KGM. Moreover, sonication contributed to off-white color by reducing the browning caused by alkali in Da-KGM products. Ultrasound-mediated heterogeneous deacetylation reaction is a feasible way to prepare Da-KGM samples with lightened browning and controllable DD. © 2022 Society of Chemical Industry.

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

Konjac flour, mainly obtained and purified from the tubers ofAmorphophallus konjac C. Koch, yields a high molecular weight (Mw) and viscous hydrocolloidal polysaccharide: konjac glucomannan (KGM). KGM has been widely applied in the food industry as a thickening and gelation agent as a result of its unique colloidal properties of effective viscosity enhancement and thermal-irreversible gelling. This review first narrates the typical commercial KGM source species, the industrial production, and the purification process of KGM flour. The structural information on native KGM, gelation mechanisms of alkali-induced deacetylated KGM (Da-KGM) hydrogel, progress on degraded KGM derivatives, cryoprotection effect, and colloidal nutrition are highlighted. Finally, the regulatory requirements of konjac flour and KGM among different countries are briefly introduced. The fine structure and physicochemical properties of KGM can be regulated in a great range via the deacetylation or degradation reaction. Here, the relationship between the physicochemical properties, such as viscosity, solubility, gelation, and nutritional effects, of native KGM, Da-KGM, and degraded KGM derivatives was preliminary established, which would provide theoretical guidance for designing KGM-based products with certain nutritional needs.

Influence of konjac glucomannan on the emulsion-filled/non-filled chicken gel: Study on intermolecular forces, microstructure and gelling properties

The aim of this study was to determine the influence of non-/deacetylated konjac glucomannan (KG/DKG) on the intermolecular forces, microstructure and gelling properties of chicken gels filled with/without high internal phase emulsion (HIPE). Results showed that a synergistic effect of HIPE and DKG addition was found with improvements on the gel hardness (5636 g) and cooking loss (0.21%). However, the co-addition of KG (2%) and HIPE could hinder hydrophobic interactions of proteins, leading to the poor gel strength of the chicken gel due to the formation of phase separation. HIPE increased the immobilized water, G′ values and gelation rates, and promoted the transformation of α-helices to β-sheets. The addition of DKG could further increase the hydrophobic interaction, hydrogen bonds and disulfide bonds, and improved the stability of HIPE droplets, leading to the formation of a compact gel network structure. The KG (≤1%) improved gelling properties of chicken gels filled with HIPE through moisture stability.

Effect of deacetylated konjac glucomannan on heat-induced structural changes and flavor binding ability of fish myosin

This work investigated the effects of deacetylated konjac glucomannan (DKGM) on heat-induced structural changes and flavor binding in bighead carp myosin. DKGM could cross-link with fish myosin to form a thermostable complex and improve the gel strength of myosin. The incorporation of DKGM increased the surface hydrophobicity and total sulfhydryl content of heat-induced myosin. Increasing DKGM concentrations resulted in a decrease in the absolute zeta potential and a continuous increase in particle size. DKGM addition significantly reduced the α-helical content of myosin with a concomitant increase in β-sheet, β-turn, and random coil content. The binding abilities of myosin to flavors were significantly enhanced by increasing amounts of DKGM, attributing to the accelerative unfolding of myosin secondary structures and the exposure of additional hydrophobic and thiol binding sites. Increased numbers of available hydroxyl groups after DKGM treatment could also cause an increase of flavor adsorption by hydrogen bonding.

表面脱乙酰魔芋及壳聚糖包埋魔芋吸附性能比较

表面脱乙酰魔芋及壳聚糖包埋魔芋吸附性能比较