Konjac Oligo-glucomannan Research Articles

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

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. 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. 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.

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.

The Purification and Biochemical Characterization of a Weissella cibaria F1 Derived β-Mannanase for Its Use in the Preparation of Konjac Oligo-Glucomannan with Immunomodulatory Properties

Mannanase with a molecular weight of 33.1 kDa was purified from Weissella cibaria F1. The F1 mannanase contained 289 amino acid residues and shared 70.0% similarity with mannanase from Bacillus subtilis (P55278 (MANB_BACIU)). The optimum reaction conditions of F1 mannanase were 50 °C and pH 6.5. After incubation at pH 4.5–8.0 and 30–60 °C for 2 h, the enzyme activity remained above 60%. The effects of metal ions on mannanase enzyme activity were measured, and Mn2+, Mg2+, and Cu2+ increased enzyme activity. The Km (16.96 ± 0.01 μmol·mL−1) and Vmax (1119.05 ± 0.14 μmol·min−1) values showed that the enzyme exhibited high affinity for locust bean gum. Mannanase was used to hydrolyze konjac glucomannan to produce konjac oligo-glucomannan (KOGM). KOGM increased the proliferation and phagocytosis of RAW264.7 macrophages and enhanced nitric oxide, and cytokine production in macrophages, which showed potent immunostimulatory activity. In this study, the advantages of mannanase derived from lactic acid bacteria were utilized to expand the application of KOGM in the medical field, which is helpful to explore the broad prospects of KOGM in functional food or medicine.

Influence of Konjac oligo-glucomannan as cryoprotectant on physicochemical and structural properties of silver carp surimi during fluctuated frozen storage

The aim of this study was to analyze the effect of Kanjoc oligo-glucomannan (KOG) on functional and structural changes in silver carp surimi during fluctuated (FLUC) frozen storage. During this study, KOG was prepared and added 1 and 3% in surimi and myofibrillar protein (MP) and compared with a positive control (PC) of sucrose and sorbitol mixture added samples. The results showed that the water holding capacity (WHC), textural and structural properties decreased during FLUC-I and FLUC-II, indicating that it could be due to protein denaturation induced by the formation of irregular crystallizations and recrystallization. Moreover, it was noted that the addition of KOG (3%) enhanced the stability of α-helix content (58–47%) during FLUC-I and (60–50%) during FLUC-II by inhibiting the hydrophobic residue exposure and change in aromatic amino acids. Meanwhile, KOG (3%) enhanced the textural properties by inhibiting the freeze induced protein denaturation. During FLUC frozen storage, the KOG (3%) was found to be a more effective concentration than conventional cryoprotectant mixture (PC). At industrial level, KOG (3%) could be used as a potential alternative to conventional cryoprotectants to attain prolonged commercial and economic values of silver carp.

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.

Prebiotic effect of porang oligo-glucomannan using fecal batch culture fermentation

Porang glucomannan is a polysaccharide extracted from Amorphophallus oncophylus and its degradation product is porang oligo-glucomannan (POG). It contains glucomannan, which has been used as an emulsifier, thickener, or as a nutritional supplement to counter many diseases. While it is believed to have health benefits, there are only limited studies exploring this aspect of porang glucomannnan (PGM). It was hydrolyzed using β-mannanase to obtain POG under optimal conditions: reaction temperature of 37 °C, reaction time of 4 h, pH 5.5 and E/S of 1:1,000 (w/w). The study aimed to evaluate the fermented POG, which might also generate short-chain fatty acids (SCFA) and to estimate the prebiotic activity score of POG fermented in vitro. The results show that SCFA profiles of POG fermentation gave a high acetic acid concentration (32.64 mM) and butyric acid (6.68 mM) at 12 h, having butyrogenic effects after a rapid fermentation. Mostly the beneficial bacteria grew faster on POG and KOG (konjac oligo-glucomannan) than on PGM or control at the beginning of incubation. Among the substrates screened, POG showed a highly positive prebiotic index of 10.29, increasing bifidobacteria and lactobacilli but reducing bacteroides population. So, POG is a candidate prebiotic since it has bifidogenic, butyrogenicity, and fermentability.

Preparation of konjac oligoglucomannans with different molecular weights and their in vitro and in vivo antioxidant activities.

In this paper, konjac oligoglucomannan (KOGM) was obtained with a hydrolysis rate of 56.24% by controlling the hydrolysis conditions. KOGM was passed through a 0.2 kDa dialysis bag, a 3 kDa ultrafiltration tube, and a 5 kDa ultrafiltration tube, creating samples with molecular weights of 0.2–3 kDa (IV), 3–5 kDa (III), and >5 kDa (II), respectively. The in vitro antioxidant activities of the KOGM samples were tested by measuring their removal effects on ˙OH, n {text{O}}_{2}^{-}n , and DPPH˙. The in vivo antioxidant activities of the samples were analyzed by measuring their impacts on the malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and glutathione peroxidase (GSH-PX) activity in mice. The results show that the KOGM samples in groups III and IV could effectively remove ˙OH, n {text{O}}_{2}^{-}n , and DPPH˙; the KOGM samples in all three groups could enhance the SOD and GSH-PX activities and reduce the MDA content in the liver tissues of mice; finally, the antioxidant activity of KOGM is negatively correlated with the molecular weight.

Amelioration of gut dysbiosis and gastrointestinal motility by konjac oligo-glucomannan on loperamide-induced constipation in mice

Konjac oligo-glucomannan (KOG) is a non-digestible dietary fiber that is resistant to digestion and absorption in gastrointestinal (GI) tract. Thus, it might be used as an alternative management for constipation. The aim of this study was to evaluate the effects of KOG on gut motility and microbiota to relieve constipation in mice. Mice received Bifidobacterium animalis, lactulose, konjac glucomannan (KGM), or KOG for 14 d. Constipation was induced by 5 mg/kg loperamide days 12 through 14 in all groups except the control. Defecation frequency, small intestinal transit, and total gut transit time were indicated by counting the number of feces, and using charcoal meal and Evans blue as markers, respectively. Smooth muscle (SM) contraction and gut motility were evaluated by organ bath and GI motility monitor system. Gut microbiota were measured by fluorescence in situ hybridization technique. KOG significantly (P < 0.01) increased defecation frequency and small intestinal transit but decreased total gut transit time when compared with the constipation-without-treatment group. These results were similar to the effects of Bifidobacterium animalis, lactulose, and KGM. KOG ameliorated the effect of loperamide on contraction frequency of distal colonic circular SM. The motility patterns were changed in the KOG group from non-propagation to propagation contraction. KOG significantly inhibited the effects of loperamide on gut microbiota by increasing the numbers of Bifidobacterium spp. and decreasing the numbers of Clostridium spp. and Bacteroides spp. These results suggest that KOG acts as a prebiotic and stimulant laxative for relief and prevention of constipation.

Physico-chemical and functional properties of silver carp myosin glycated with konjac oligo-glucomannan: Effects of deacetylation

The glycation of silver carp myosin (Ms) with konjac oligo-glucomannan (KOG) of different degrees of deacetylation (DD) was investigated. As DD increased, the physico-chemical and functional properties of glycoconjugates changed. The available lysine content decreased, while grafting degree and total sulfhydryl group increased, andmeanwhile, the isoelectric point (pI) reduced. SDS-PAGE analysis indicated that glycation can be promoted as the increase of DD. The solubility increased significantly both in 0.1 M and 0.5 M NaCl solution, and the thermal stability increased when heated for 60 min at 80 °C. The emulsifying activity index (EAI) and emulsifying stability index (ESI) increased as well. These results showed that the highly deacetylated KOG (DKOG) was easier to glycate with myosin, leading to a great improvement in functional properties of myosin. It can be suggested that the reduction in steric hindrance of DKOG as a result of removal of acetyl groups facilitated the glycation.

Optimization on production of konjac oligo-glucomannan and their effect on the gut microbiota.

Konjac glucomannan (KGM) is a polysaccharide extracted from Amorphophallus konjac, and its degradation product is konjac oligo‐glucomannan (KOG). The aim of this study was to produce KOG from KGM and to evaluate its effect on the gut microbiota in fecal batch culture. KOG was produced by enzymatic hydrolysis using β‐mannanase. The optimum conditions were as follows: reaction temperature of 48°C, reaction time of 4 hr, pH of 5.5 and E/S of 0.05% followed by purification step using 3,000 NMWC ultrafiltration (UF) membrane pore size. The effect of KOG on changes in human fecal bacterial populations and short‐chain fatty acids (SCFAs) production was evaluated. The results showed that low‐molecular weight KOG (LKOG) from purification step with concentration of 9.54 mg/ml, and a prebiotic index (PI) of 0.76 was successfully produced. LKOG can enhance the production of butyric acid in the colon with the highest concentration (8.24 mM) found at 72 hr fermentation.

Structural changes of silver carp myosin glycated with Konjac oligo-glucomannan: Effects of deacetylation

The glycation of silver carp (Hypophthalmichthys molitrix) myosin (Ms) with konjac oligo-glucomannan (KOG) of different deacetylation degrees (DDs) was investigated, in an attempt to detect the structural changes of myosin. As DD increased in KOG, glycation changed the composition of amino acids in myosin, and the surface hydrophobicity (H0) of glycoconjugates decreased. Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectroscopy exhibited the significant changes of the primary and secondary structure. The increase of denaturation temperature from DSC spectra and the changes of intrinsic fluorescence emission spectra revealed that the changes in the folded state of myosin occurred, indicating that the thermal stability or the tertiary/quaternary structural stability of myosin can be improved by the glycation with KOG of different DDs. The results from scanning electron microscope (SEM) and atomic force microscope (AFM) demonstrated that when deacetylated KOGs (DKOGs) were used as sugar donor, the glycoconjugates were larger and the surface structure is more dispersed than myosin alone. It can be suggested that myosin holds a more flexible conformation after glycation with DKOGs, which is more suitable for its various excellent functional properties.

Effects of konjac oligo-glucomannan on the physicochemical properties of frozen surimi from red gurnard (Aspitrigla cuculus)

In this study, the effects of konjac oligo-glucomannan (KOG) on the physicochemical properties of frozen surimi from red gurnard (Aspitrigla cuculus) during frozen storage at −18 °C for 50 days were investigated. An aliquot of 0.5% (w/w) of KOG was added into the surimi and subjected to frozen storage (KOG group), and 8% of a conventional cryoprotectant (4% sorbitol and 4% sucrose, w/w) was used as a positive control (S group). The salt soluble protein content, the Ca2+-ATPase activity, total sulfhydryl (SH) content, gel strength, thiobarbituric acid (TBA) value, and whiteness of frozen surimi were determined. After storage for 50 days at −18 °C, the contents of salt soluble protein of KOG group and S group were 14.81% and 21.27% higher than the control, respectively, and the total SH contents of KOG group and S group were 6.90% and 8.46% higher than the control, respectively, and the gel strengths of KOG group and S group were 10.85% and 11.89% higher than the control, respectively. Although the activities of Ca2+-ATPase of KOG group and S group reached to 0.10 ± 0.02 μmol Pi/mg•min−1 and 0.11 ± 0.01 μmol Pi/mg•min−1 after 50 days, respectively, they are significantly different from the control (0.04 ± 0.02) μmol Pi/mg•min−1, which indicated a strong cryoprotective effect of KOG. KOG exhibited more powerful antioxidant activity with lower TBA values than S group. It can be concluded that the addition of conventional cryoprotectant and KOG can inhibit protein denaturation and reduce the decrease of gel strength, but KOG displayed a stronger antioxidant activity with a small addition amount of only 0.5%, despite having no effect to improve the whiteness. These make KOG a promising cryoprotectant candidate using in frozen surimi industry.

Preparation and cellular protection against oxidation of Konjac oligosaccharides obtained by combination of γ-irradiation and enzymatic hydrolysis

Konjac glucomannan (KGM) is an important source for preparation of Konjac oligo-glucomannan (KOG), but high molecular weight and viscosity in KGM inhibited its full degradation into KOG. In this study, KOG with a degree of polymerization between 2 and 9 was obtained by combining γ-irradiation and enzymatic hydrolysis in high yield. We investigated the protective effect of KOG against H2O2 - induced oxidative damage in vitro, using human hepatic cell line (LO2) as a cell model. Our results demonstrated that pretreating LO2 with KOG significantly increases cellular survival and antioxidant activities of GSH-Px and CAT enzymes, and reduces levels of LDH, MDA, intracellular accumulation of ROS and Ca2+ concentration within the cell. Marked protective effect against oxidative damage, in addition to obtained high yield of KOG, supports its potential use as an abundant source of antioxidant. To conclude, our study provided a theoretical perspective for future uses of KGM.

Physicochemical, conformational and functional properties of silver carp myosin glycated with konjac oligo-glucomannan: Implications for structure-function relationships

Silver carp myosin (Ms) was glycated with konjac oligo-glucomannan (KOG) under dry reaction conditions. The physicochemical properties (amino acid composition, total sulfhydryl groups, hydrophobicity, viscosity and microstructure), conformational properties (heat changes, secondary and tertiary conformations) and functional properties (emulsifying properties) were investigated. The amino acid composition (especially relative acidic/basic charged amino acid ratio) was an intrinsic physicochemical parameter that largely determined other physicochemical and conformational properties. Formation of Ms-KOG conjugates reduced the total sulfhydryl groups content and hydrophobicity. Glycation for 12 h increased the viscosity of Ms by 35-fold. Nanoscale structure and secondary conformation, as determined by atomic force microscopy and far-UV circular dichroism spectroscopy, remarkably changed. Combined analysis of differential scanning calorimetry and intrinsic emission fluorescence indicated that Ms may undergo a tertiary conformation unfolding and subsequent rearrangement process. More importantly, we have interestingly found that KOG improved the flexibility in conformation and enhanced the steric hindrance of Ms. This specific structure of Ms-KOG eventually improved the emulsifying properties.

Physicochemical and functional properties of silver carp (Hypophthalmichthys molitrix) myofibrillar protein glycated with konjac oligo-glucomannan

Konjac oligo-glucomannan (KOG) is a new-type polysaccharide with abundant hydroxyl groups and a small quantity of branches. Myofibrillar protein (Mf) from silver carp (Hypophthalmichthys molitrix) was incubated with KOG for 0–96 h at 50 °C and 75% relative humidity to obtain glycoconjugates in different periods of Maillard reaction. Physicochemical properties, including SDS-PAGE, sugars bound to Mf, available amino acids and FT-IR property all indicated that glycation occurred successfully. In addition, activity of Ca2+-ATPase decreased markedly due to thermal denaturation and glycation of Mf. Functional properties of Maillard reaction productions (MRPs), such as solubility, heat stability and emulsion properties were all superior to Mf. Solubility and emulsion properties reached the highest value at 8–12 h of the reaction, and then decreased severely. However, heat stability decreased at 2–5 h of glycation, and then increased significantly. In conclusion, KOG is an excellent sugar donator to improve functional properties of Mf by glycation.

Characterization of silver carp (Hypophthalmichthys molitrix) myosin protein glycated with konjac oligo-glucomannan

Silver carp (Hypophthalmichthys molitrix) myosin protein (Ms) was glycated with konjac oligo-glucomannan (KOG) by using the controlled Maillard reaction (MR). Colorimeter measurements and SDS-PAGE analysis indicated the occurrence of the MR and glycoconjugates formation, respectively. Thinner sheet and non-homogeneous Ms-KOG conjugates were observed by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FT-IR) indicated that the amide I, II and III bands of Ms were changed by the glycation. Glycation lowered the isoelectric point from 5.3 to 3.8 when incubated for 96 h. Ms became highly soluble in 0.1 M NaCl with the decrease of 23.6% of the total lysine residues at the reaction time of 12 h. The thermal stability of Ms glycated with KOG for 24 h was effectively improved from 61.4% to 95.8% when heated at 80 °C for 60 min. These results suggested that MR with KOG can be a promising way to improve functional properties of Ms.

Characterization of Sulfate Groups and Assessment of Anti-Coagulant Activity of Glucomannan Sulfate Prepared from Konjac Glucomannan

Purpose: To determine the structure of Konjac glucomannan sulfate (KOGMS) including homogeneity, sulfate group composition as well as its anti-coagulant activity in vitro.Methods: KOGMS was prepared using chlorosulfonic acid and N, N-dicyclohexyl carbodiimide (DCC) from konjac oligo-glucomannan (KOGM). Homogeneity analysis was confirmed by cellulose acetate membrane electrophoresis. Fourier transform infrared FT-IR spectra, Laser Raman spectra and 13C Nuclear Magnetic Resonance NMR spectra were obtained and used to analyze the sulfate groups. The anti-coagulant activity of KOGM and KOGMS was evaluated in vitro using activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) as indicators.Results: KOGMS was shown to be a homogenous carbohydrate with a relative molecular mass ranging from 5.8 × 103 to 6.2 × 103 Da and various degrees of substitution (DS) ranging from 1.28 to 1.81. The sulfate groups were inserted at C-2, C-6 and C-3 positions of KOGM. The APTT of human platelet-poor plasma containing KOGMS was 47.2 s which was close to that of heparin at a concentration of 0.5mg/mL. Furthermore, the APTT of human platelet-poor plasma containing KOGM was only 15.6 s whichis close to that of the negative control group. For KOGMS, the values obtained in all three tests were significantly higher than those of KOGM and the negative control group (p &lt; 0.05).Conclusion: Hydroxyl groups can be substituted efficiently by sulfated groups at C-2, C-6 and C-3 positions of KOGM with little degree of degradation. In vitro anti-coagulant activity data indicates that KOGMS has a significantly stronger anti-coagulant activity than KOGM due probably to the sulfated groups in the main chain of its molecule.Keywords: Konjac, Oligo-glucomannan Sulfate, Laser Raman Spectra, Anticoagulant Activity

Preparation, composition analysis and antioxidant activities of konjac oligo-glucomannan

Konjac oligo-glucomannan (KOG) was prepared by degradation of konjac glucomannan (KG) using β-mannanase. The hydrolysis process was monitored by the viscosity of the enzymatic hydrolysates. Factors affecting the enzymatic hydrolysis of KG were investigated, and the optimum hydrolysis conditions were as follows: time 2h; temperature 50°C; pH 6.0; and enzymatic concentration 150U/g. Under these optimized conditions, minimum viscosity (31.9mPa·s) of the hydrolasate was obtained. The average degree of polymerization (DP) of the resulting KOG was approximately equal to 5.2. The results of Fourier transform infrared (FTIR) spectra of KG and KOG indicated that KG was successfully degraded. In addition, their antioxidant activities were evaluated by determination of hydroxyl radical (•OH) and 1,1-diphenyl-2-picrylhrazyl radical (•DPPH) scavenging activity, and determination of reducing power. The results showed that KOG exhibited significant antioxidant activities. Taken together, this study suggested that KOG could potentially be used as a natural antioxidant.