Highly Biocompatible Antibacterial Hydrogel for Wearable Sensing of Macro and Microscale Human Body Motions.

Flexible electronics, like electronic skin (e-skin), rely on stretchable conductive materials that integrate diverse components to enhance mechanical, electrical, and interfacial properties. However, poor biocompatibility, bacterial infections, and limited compatibility of functional additives within polymer matrices hinder healthcare sensors' performance. This study addresses these challenges by developing an antibacterial hydrogel using polyvinyl alcohol (PVA), konjac glucomannan (KGM), borax (B), and flower-shaped silver nanoparticles (F-AgNPs), referred as PKB/F-AgNPs hydrogel. The developed hydrogel forms a hierarchical network structure, with a tensile strength of 96 kPa, 83% self-healing efficiency within 60 minutes, and 128% cell viability in Cell Counting Kit-8 (CCK-8) assays, indicating excellent biocompatibility. It also shows strong antibacterial efficacy against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Blue light irradiation enhances its antibacterial activity by 1.3-fold for E. coli and 2.2-fold for S. aureus. The hydrogel's antibacterial effectiveness is assessed by monitoring changes in electrical conductivity, providing a cost-effective alternative to traditional microbial culture assays. The PKB/F-AgNPs hydrogel's flexibility and electrical conductivity enable it to function as strain sensors for detecting body movements and facial expressions. This antibacterial hydrogel underscores its potential for future human-machine interfaces and wearable electronics.

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.

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.

Konjac glucomannan attenuate high-fat diet-fed obesity through enhancing ß-adrenergic-mediated thermogenesis in inguinal white adipose tissue in mice.

Konjac glucomannan (KGM) has been reported to prevent high-fat diet-induced obesity, and we study investigated whether dietary supplementation with KGM can prevent obesity by increasing energy expenditure in inguinal white adipose tissue (iWAT) of high-fat diet (HF) -fed mice. Weaned mice fed the control diet (Con), HF, or HF plus KGM (8%, w/w, HFK) were divided into three groups. The results showed that 10-week supplementation with KGM significantly reduced partial adipose tissue weight and body weight, and improved glucose tolerance. Compared to the HF group, plasma lipid concentrations in the HFK group were greatly decreased to the control level. Moreover, transcriptomic research has shown that genes that are mainly associated with energy and lipid metabolism are significantly altered in iWAT. Mechanistically, KGM stimulated thermogenesis by promoting the expression of uncoupling protein-1 (UCP1) and the ß3-adrenergic receptor (ADR3ß). Taken together, our results suggest that dietary supplementation with konjac glucomannan can effectively alleviate obesity induced by a high-fat diet by activating ADR3ß-mediated iWAT thermogenesis. Dietary supplementation with KGM can effectively alleviate high fat diet- induced obesity mice by via activating ADR3ß-mediated thermogenesis of iWAT.

Study on the Influence of the Preparation Method of Konjac Glucomannan-Silica Aerogels on the Microstructure, Thermal Insulation, and Flame-Retardant Properties.

Natural polysaccharides with high viscosity, good thermal stability, and biocompatibility can improve the mechanical properties of inorganic silica aerogels and enhance their application safety. However, the effects of the preparation methods of polysaccharide-silica aerogels on their microstructure and application properties have not been systematically studied. To better investigate the effect of the microstructure on the properties of aerogel materials, two aerogels with different structures were prepared using Konjac glucomannan (KGM) and tetraethoxysilane (TEOS) via physical blending (KTB) and co-precursor methods (KTC), respectively. The structural differences between the KTB and KTC aerogels were characterized, and the thermal insulation and fire-retardant properties were further investigated. The compressive strength of the KTC aerogels with a cross-linked interpenetrating network (IPN) structure was three times higher than that of the KTB aerogels, while their thermal conductivity was 1/3 of that of the KTB aerogels. The maximum limiting oxygen index (LOI) of the KTC aerogels was 1.4 times, the low peak heat release rate (PHRR) was reduced by 61.45%, and the lowest total heat release (THR) was reduced by 41.35% compared with the KTB aerogels. The results showed that the KTC aerogels with the IPN have better mechanical properties, thermal insulation, and fire-retardant properties than the simple physically blending KTB aerogels. This may be due to the stronger hydrogen-bonding interactions between KGM and silica molecules in the KTC aerogels under the unique forcing effect of the IPN, thus enhancing their structural stability and achieving complementary properties. This work will provide new ideas for the microstructure design of aerogels and the research of new thermal insulation and fire-retardant aerogels.

One-Step Fabrication of Recyclable Konjac Glucomannan-Based Magnetic Nanoparticles for Highly Efficient Cr(VI) Adsorption.

Recently, the natural polymer polysaccharide konjac glucomannan (KGM) has received attention as a promising adsorbent in water treatment due to its low toxicity, cost-effectiveness and biocompatibility. However, the high-level water absorbency of KGM makes it difficult to recover in water treatment. In this study, by combining KGM with magnetic nanoparticles, KGM-based magnetic nanoparticles (KGM-Fe3O4 NPs) with excellent adsorption properties and recyclability for heavy metals were prepared using an one-step precipitation method. The as-prepared KGM-Fe3O4 NPs have a spherical morphology of superparamagnetism with a small particle size (ca. 7.0 nm) and a large specific surface area (160.1 m2·g-1). Taking Cr(VI) as the target heavy metal ion, the above nanoparticles have a high adsorption capacity and fast adsorption rate for Cr(VI). The pseudo-second order kinetic model is more suitable to describe the adsorption process of Cr(VI) by KGM-Fe3O4 NPs, and the maximum adsorption capacity of Cr(VI) onto KGM-Fe3O4 NPs was calculated to be 41.67 mg·g-1 using the Langmuir isotherm model. In addition, KGM-Fe3O4 NPs with adsorbed heavy metal ions can be quickly recovered from a solution, regenerated, and reused in the next cycle. KGM-based Fe3O4 nanoparticles are promising adsorbents that show significant reusability for the removal of metal ions in water and wastewater treatment.

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.

Preparation and Performance of Thickened Liquids for Patients with Konjac Glucomannan-Mediated Dysphagia.

The present study sought to characterize the rheological and thickening properties of Konjac glucomannan (KGM) and prepare thickening components for special medical purposes using KGM and maltodextrin as the primary raw materials and guar gum (GG), xanthan gum (XG), locust bean gum (LBG), and carrageenan (KC) as the supplemented materials. The formulation and preparation processes were optimized through single factor experiments taking sensory evaluation as an indicator. The results confirm that KGM had excellent thickening performance, reaching about 90 times its own mass. The optimal formulation process of the thickening components based on KGM was as follows: the mass concentration of the compound thickener (KGM/GG/XG/LBG/KC = 13:2:2:2:1) was 5.0-7.0 mg/mL; the maltodextrin concentration was 10.0 mg/mL; the brewing temperature of the thickening component was 60 °C with no restriction on consumption time. The rheology test results revealed that the thickening components had shear thinning characteristics, which could provide three different thickening effects of nectar-thick level (350 mPa·s), honey-thick level (1250 mPa·s), and pudding-thick level (1810 mPa·s) suitable for people with different degrees of chewing disorders. Overall, this study provides a theoretical basis and technical reference for KGM as a dietary nutrition support for patients with dysphagia.

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

BACKGROUND: 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. RESULTS: 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 (0.10 mol 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. CONCLUSION: 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.

The impact of konjac glucomannan on the physical and chemical stability of walnut oil-in-water emulsions coated by whey proteins.

BACKGROUND: Walnut oil, which is rich in polyunsaturated fatty acids (PUFAs), can be incorporated into food emulsions to increase their nutritional value. However, these emulsions are highly susceptible to deterioration during storage due to lipid oxidation. Konjac glucomannan (KGM) is a neutral plant polysaccharide used as a stabilizer, thickener or gelling agent in foods. The goal of this study was to incorporate KGM into oil-in-water emulsions containing walnut oil droplets coated by whey protein isolate (WPI) and then determine its effects on their physical and oxidative stability. RESULTS: At pH 3, inclusion of KGM (0.1-1 g kg-1 ) reduced the positive surface potential on the droplets in the emulsions and modified the secondary structure of the adsorbed whey proteins, suggesting an interaction between KGM and WPI at the droplet surfaces. The physical stability of the emulsions was enhanced when 0.1-0.6 g kg-1 KGM was added but reduced at higher levels. Lipid oxidation was inhibited in the emulsions in a dose-dependent manner when 0.2-0.6 g kg-1 KGM was added but protein oxidation was promoted at higher KGM levels. The steric hindrance provided by the thick WPI-KGM interfaces, as well as the ability of the polysaccharides to modify the antioxidant properties of the adsorbed proteins, may account for these effects. CONCLUSION: These results suggest that KGM can be used to inhibit lipid oxidation in emulsified foods containing protein-coated oil droplets. However, its level must be optimized because higher doses can result in droplet aggregation and protein oxidation. © 2022 Society of Chemical Industry.

Effects of konjac glucomannan on the long-term retrogradation and shelf life of boiled wheat noodles.

BACKGROUND: Starch retrogradation and moisture migration of boiled wheat noodles (BWNs) result in quality deterioration and short shelf life. The objective of this research was to investigate whether konjac glucomannan (KGM) could improve the quality of BWNs and further establish the shelf-life prediction model. RESULTS: The moisture distribution, recrystallization, and thermal properties of BWNs during refrigerated or ambient temperature storage were determined. Low-field nuclear magnetic resonance data showed that KGM addition induced left-shifts of T21 and T22 values, indicating that KGM limited the mobility of bound and immobile water among noodle matrices. X-ray diffraction spectra revealed that KGM did not change the crystal patterns of BWNs but could inhibit the starch recrystallization after refrigerated storage. The Tp and ΔH values of retrograded samples notably (P < 0.05) decreased with the increase of KGM addition, suggesting the hinderance of starch retrogradation behavior by KGM. The shelf life of BWNs was predicted by accelerated storage test combined with the Arrhenius equation. The present data displayed that the predicted shelf life of vacuum-packed and sterilized BWNs with 10 g kg-1 KGM at 25 °C was 733 days, 2.4-fold that of the control group. CONCLUSION: BWNs with KGM addition could inhibit starch retrogradation and improve the storage stability, consequently promoting noodle quality. © 2021 Society of Chemical Industry.

Structural characterization and antibacterial properties of konjac glucomannan/soluble green tea powder blend films for food packaging.

Antimicrobial activity is a promising property for food packaging which could prolong the shelf life of food products. In this paper, the physicochemical and antimicrobial properties of konjac glucomannan (KGM)/soluble green tea powder (SGTP) edible films were firstly prepared and analyzed through light barrier properties, Fourier transform infrared spectroscopy (FT-IR), tensile strength (TS), X-ray diffraction (XRD), thermogravimetric analysis and scanning electron microscope (SEM). The results showed that appropriate addition of SGTP could improve the TS of composite films. With the increase of SGTP content, the transmittance of the films in the ultraviolet region decreased obviously, and the thermal stability was improved in a SGTP dependent manner. KGM/SGTP films present a fairly smooth and flat surface without any fracture when 0.5% SGTP was provided. The bacteriostatic test showed that the bacteriostatic performance of the composite films against Staphylococcus aureus and Escherichia coli was also significantly enhanced. When 1% SGTP was provided, the zones of inhibition for Escherichia coli and Staphyloccocus aureus reached to 13.45 ± 0.94 mm and 13.76 ± 0.92 mm, respectively. Overall, the KGM/SGTP films showed great potential as bioactive packaging materials to extend food shelf life.

Effects of konjac glucomannan/pomegranate peel extract composite coating on the quality and nutritional properties of fresh-cut kiwifruit and green bell pepper.

The effects of an edible coating, based on konjac glucomannan (KG) incorporated with pomegranate peel extracts (PE), on the physicochemical and nutritional properties of fresh-cut kiwifruit and green bell pepper during storage were investigated. The optimal extract time (40.6 min), temperature (54.5 °C), and ultrasound power (255.5 W) with response surface method, provided a high total antioxidant activity (TAA) of (92.31 ± 1.43)%. Fresh-cut kiwifruit and green bell pepper were coated by dipping using five treatments (distilled water, ascorbic acid, KG, PE, KG + PE), packed into polymeric film and stored for 8 days at 10 °C. Distilled water treatment was used as control. KG + PE treatment resulted in the highest total soluble solid and titratable acidity in fresh-cut kiwifruit, while the maximum firmness in fresh-cut green bell pepper. The weight loss was both effectively decreased in samples treated with KG or KG + PE. All samples treated with KG + PE had significantly higher contents of chlorophyll, ascorbic acid, total phenolic and TAA than others. Moreover, the KG + PE group had the lowest counts of microorganisms in all samples. KG coating incorporated with PE was proved to be efficient in maintaining the physico-chemical and nutritional properties of fresh-cut kiwifruit and green bell pepper during low temperature storage compared with control. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05006-7.

Rheological and microstructural characterization of wheat dough formulated with konjac glucomannan.

BACKGROUND: This work aimed to investigate the effects of different levels of konjac glucomannan (KGM) on the thermomechanical and pasting properties, water distribution, gelatinization, texture, and microstructural characteristics of wheat flour and dough. RESULTS: The thermomechanical properties assessed with a Mixolab showed that KGM could increase the water absorption and degree of softening and decrease the stability time of wheat dough. In addition, wheat flour starch with KGM underwent significant (P < 0.05) gelatinization changes according to the rapid viscosity analyzer and differential scanning calorimetry results. These results demonstrated that KGM enhanced the thermal stability and anti-aging capacity of wheat flour. All doughs with KGM exhibited viscoelastic behavior but lower hardness and gumminess. Low-field nuclear magnetic resonance showed that water, with a tight binding force, migrated to the weaker binding forces in the dough. A noticeable disruption of the gluten network was observed at the highest level of KGM. However, an intermediate level of KGM addition (10 or 15 g kg-1 flour) still rendered dough with satisfactory properties. CONCLUSION: A certain amount of KGM could enhance the thermal stability and anti-aging ability of wheat flour, improve the viscoelastic behavior, and decrease the hardness and gumminess of dough. In general, the mixing of flour and dough with KGM addition of 10 or 15 g kg-1 flour was of good quality. © 2021 Society of Chemical Industry.

An innovative konjac glucomannan/κ-carrageenan mixed tensile gel.

BACKGROUND: Konjac glucomannan (KGM) showed a synergistic interaction with κ-carrageenan (CAR), which led to the formation of a promising compound hydrocolloid gel in the food field (such as jelly). Nevertheless, the mixed gels formed by adding KGM to CAR still displayed defects in gel strength and syneresis, and would hardly meet the quality requirements of some gel foods. However, deacetylated KGM and maltodextrin (MD) have always been used in gel foods and affect their viscosity and rheological properties. RESULTS: In our paper, different amounts of MD were first used to alter the textural properties, and the results showed that both tensile strength and elongation exhibited first an increasing and then a decreasing trend with the increasing MD proportion and achieved a maximum at a final maltodextrin proportion of 4 g kg-1 in the KGM/CAR/MD system. Based on the above results, we further explored the effects of deacetylation degree of KGM on the gel properties of mixed gel system. The results revealed that, compared to the native KGM, the partial deacetylated KGM was capable of significantly improving the tensile strength and elongation of KGM/CAR mixed gel. CONCLUSION: Our study found that the appropriate addition of MD (0.4%) and DKGM were able to alter the tensile properties of KGM/CAR mixed gel, with potential to meet the needs of consumers and further design innovative tensile gel products in the soft gel industry. © 2021 Society of Chemical Industry.

Konjac glucomannan polysaccharide and inulin oligosaccharide enhance the colonic mucosal barrier function and modulate gut-associated lymphoid tissue immunity in C57BL/6J mice.

Both konjac glucomannan (KGM) and inulin oligosaccharide have been shown to improve bowel function, but their effects on the mucosal barrier function and immunity are not fully understood. The aim of the present study was to determine the effects of a low-level supplementation of dietary fibres on the colonic mucosal barrier function, antioxidant enzyme defence and immunity. C57BL/6J mice (6 weeks of age, eight per group) were randomly assigned to consume one of the following diets: control or control diet supplemented with 2 % (w/w) of KGM, inulin oligosaccharide (degree polymerisation = 8) or KGM+inulin (1 %, w/w each (K+I)). Fresh faeces were collected on days 19-21. Mice were killed on day 22 after fasting. Segments of colon tissues were processed for histological procedure and stained for acidic mucins and tight junction protein marker zona occludin-1 (ZO-1). The remaining tissues were processed to determine the gene expression of mucin 2, tight junction proteins, antioxidant enzymes and cytokines. The plasma cytokines were measured. Results indicated that KGM, inulin and K+I significantly increased the mucosal layer thickness, mucin density (granule number/crypt) and gene expression of Muc2 as compared with the control. All fibre treatments increased the gene expressions of ZO-1, occludin, glutathione peroxidase, glutathione S-transferase π, catalase and IL-10. In addition, all fibre treatments increased faecal butyrate and probiotics, and plasma IL-10 concentrations. In conclusion, supplementation of low-level, 2 % (w/w), of K+I was sufficient to enhance the mucosal barrier function and anti-inflammatory status.

Synbiotic edible film from konjac glucomannan composed of Lactobacillus casei-01® and Orafti®GR, and its application as coating on bread buns.

BACKGROUND: Konjac glucomannan-based edible films formulated with Lactobacillus casei-01® and chicory-derived inulin Orafti®GR were studied for their properties, stability, and application as coatings on bread buns. RESULTS: Thickness and transparency were variable and dependent on the formulations. Alterations in color properties of all supplemented films were unnoticeable by unaided human eyes, with ΔE less than 3. Lactobacillus casei-01® and Orafti®GR were associated with higher water solubility of the films. Lactobacillus casei-01® decreased the water vapor permeability of the films while Orafti®GR promoted it. The mechanical properties in all combinations remained unchanged, although those with Orafti®GR showed profoundly reduced tensile strength. Scanning electron micrographs and Fourier transform infrared spectra of the films confirmed good homogeneity and intermolecular attraction between the prebiotic and konjac glucomannan. Cell viability in the films stored at room temperature decreased sharply, becoming less than the minimum recommended level after day 4, while viable L. casei-01® in coatings on bread buns gradually decreased, with a reduction of ca. 2 log colony-forming units (CFU) portion-1 over the 7 day storage period at room temperature. CONCLUSION: The synbiotic film and coating developed in this study are a relatively simple strategy for incorporating L. casei-01® and Orafti®GR into bread buns, which are short shelf-life foods. Bread buns with synbiotic coating could diversify functional food choices. Pretreatment, together with other technologies, is required to maintain a desirable number of active probiotic cells for longer. © 2020 Society of Chemical Industry.

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

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

[Research progress on functional soft candy of traditional Chinese medicine].

Functional soft candy of traditional Chinese medicine( TCM) can be used to supplement vitamins,enhance immunity,assist in lowering blood sugar,assist in lowering blood lipid,assist in lowering blood pressure,relax the bowel,reduce weight and fight againstoxidation.It has attracted much attention due to its effective improvement in the bad taste and incompatibility of traditional medicines.TCM functional soft candy and health food made by gel,sweetener and Chinese herbal medicines( which can be used both as food and medicine) approved by the State Food and Drug Administration were selected as the research objects in this paper.We combed and analyzed the research situation of health food dosage forms and effects,the functional factors of TCM functional soft candy,gelatin,sweetener,production process,and quality evaluation,etc.,and then,we discussed their existing problems and development prospects.After reviewing the relevant literature on TCM functional soft candy and health food researches published in recent years,we analyzed and summarized their dosage forms,health effects,gels,sweeteners,production process,quality evaluation and safety.The following problems in the research of TCM functional soft candy were pointed out: for examples,differences in the sensory evaluation of soft candy;whether the combination of several similar gels and sweeteners had an effect on human health; the lack of laws and regulations in health foods and the lack of uniform standards for quality evaluation.In summary,TCM functional soft candy is a new type of health food,which changes the dosage form of health food based on capsules and tablets.This move conforms to the physiological and psychological needs of consumers.Therefore,it is in line with the requirement of " Health China 2030" Planning Outline.

Konjac glucomannan-based composite films fabricated in the presence of carnauba wax emulsion: hydrophobicity, mechanical and microstructural properties evaluation.

Despite the excellent characteristics of carnauba wax (CW), hydrophobicity in particular, its complementary effect on the enhancement of konjac glucomannan (KGM) films remains poorly documented. KGM is a promising food bio-packaging material with excellent film-forming abilities, which could be improved further through modification of its hydrophilic nature using CW. In this study, emulsified composite films (KW) of KGM incorporated with varied CW concentration levels (0%, 4%, 8%, 12%, 16% and 20% w/w) were successfully prepared by solvent casting method. Increasing CW in KW films significantly improved the hydrophobicity, barrier and mechanical properties. The recorded improvements in functional properties relative to KGM films include fivefold solubility reduction, twofold contact angle and strength increment, as well as significant increase in stretch (61%) and decrease in water vapour transmission rate (48%). Microstructure analyses using scanning electron microscopy demonstrated remarkable improvements in cohesiveness, smoothness and homogeneity in KW aggregates with higher CW concentrations. Generally, our findings reveal the potential use of KW films as food packaging material which could reduce the availability of unsafe and environmentally unfriendly food packages in the market.