Effect of gamma irradiation on structure, physicochemical and functional properties of bitter vetch (Vicia ervilia) seeds polysaccharides

Gamma rays irradiated polysaccharides: A review of the structure, physicochemical properties, biological activities alteration, and future food applications

Recently, there has been a growing interest in using radiation to change various properties of polysaccharides. This review gives a more detailed examination of the effects of gamma radiation on polysaccharides and its association with their techno-functional and biological properties following irradiation. Gamma irradiation is a potent tool for modifying the structure and properties of polysaccharides, enhancing their functionality in food applications. This review explores the effects of gamma irradiation on polysaccharides, focusing on changes in their molecular structure, physicochemical properties, and biological activities. Gamma irradiation induces chain scission and cross-linking in polysaccharides, leading to alterations in molecular weight, solubility, and viscosity. These structural modifications often enhance antioxidants, antimicrobial, and anti-inflammatory activities, expanding their potential use in food products. Gamma-irradiated polysaccharides exhibit improved gelation, emulsification, and film-forming abilities, making them suitable for various food applications such as thickeners, stabilizers, and edible coatings. The review also discusses the safety and regulatory aspects of using gamma-irradiated polysaccharides in food products. Future research directions are proposed to optimize irradiation conditions and further explore the multifunctional benefits of these modified polysaccharides, ultimately contributing to the development of innovative, functional food products.

Digestive characteristics of Tibetan tea polyphenols and polysaccharides in vitro and their effects on gut microbiota

Tibetan tea contains highly valuable bioactive components like polyphenols and polysaccharides, which can regulate gut microbiota and promote bodily health. This study systematically investigated the gastrointestinal digestion and colonic fermentation behavior of Tibetan tea polyphenols (TPP), polysaccharides (TPS), and their polyphenol-polysaccharide complex (TC). TPP, TPS, and TC demonstrated minimal changes in physicochemical and structural characteristics after gastrointestinal digestion. Following 24 h of fecal fermentation, all components significantly degraded and altered microbial composition (pH decreased to 6.44, 5.76, and 6.14, respectively), promoting dominant flora such as Phascolarctobacterium and Lachnoclostridium. Differentially, TPS and TC demonstrated stronger promotion of dominant Bifidobacterium, Faecalibacterium, and Collinsella, whereas TPP preferentially enriched Megasphaera and Butyricicoccus. Additionally, fermentation markedly increased the concentration of short-chain fatty acids (SCFAs), with TPS yielding the highest total SCFAs (17.29 ± 0.50 mM), particularly acetic and propionic acids. Overall, Tibetan tea polyphenols and polysaccharides may serve as potential prebiotics to improve intestinal health.

Extraction optimization, purification, characterization, and hypolipidemic activities of polysaccharide from pumpkin

Polysaccharides derived from pumpkin have garnered increasing interest due to their diverse biological activities. In this study, pumpkin polysaccharides were extracted using an ultrasound-assisted extraction method, optimized via response surface methodology. The optimal extraction conditions were identified as follows: a solid-liquid ratio of 1:60 (g/mL), an extraction time of 1.9 h, an extraction temperature of 62 °C, and an ultrasonic power of 286 W. Under these conditions, the total carbohydrate content in pumpkin polysaccharides reached 71.14 ± 1.53 %, closely aligning with the predicted value. Post extraction, the polysaccharides were purified using DEAE Sepharose Fast Flow and Sephadex G-100 columns, resulting in a pure fraction termed PPS3. Structural analysis revealed that PPS3, with a molecular mass of 5.96 × 104 Da, consisted of mannose, glucosamine hydrochloride, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, and arabinose in a molar ratio of 0.005:0.004:0.041:0.013:0.545:0.004:0.241:0.147, respectively. The backbone primarily contained →4)-α-D-GalpA-6-OMe-(1→ residue with several branched chains. Functionally, PPS3 demonstrated potent in vitro hypolipidemic activities. These findings elucidated the structural characteristics of pumpkin polysaccharides and suggested their potential as natural hypolipidemic agents.

A Novel Polysaccharide From Tremella fuciformis Alleviated High-Fat Diet-Induced Obesity by Promoting AMPK/PINK1/PRKN-Mediated Mitophagy in Mice

SCOPE

Polysaccharides from Tremella fuciformis have gained significant interest due to their diverse biological activities. This study focuses on characterizing a purified polysaccharide, TPSP2, extracted from T. fuciformis and evaluating its antiobesity effect and underlying mechanisms in vivo.

METHODS AND RESULTS

Structural analysis revealed that TPSP2, with a molecular weight of 1.51 × 103 kDa, is composed of mannose, rhamnose, glucuronic acid, galactose, xylose, arabinose, and fucose in specific molar ratios. The primary linkages identified include t-Fuc(p), 1,2-Xyl(p), t-GlcA(p), 1,3-Man(p), and 1,2,3-Man(p), with their corresponding ratios being 12.987%, 11.404%, 16.050%, 16.527%, and 26.624%, respectively. In vivo experiments demonstrated that TPSP2 significantly alleviated high-fat diet-induced weight gain, hyperlipidemia, hepatic steatosis, hyperglycemia, and insulin resistance in mice. Mechanistically, TPSP2 was found to enhance AMPK/PINK1-PRKN-dependent mitophagy by upregulating the p-AMPK/AMPK ratio, LC3-II/I ratio, and expression of PINK1, PRKN, prohibitin 2 (PHB2), and LAMP2, while downregulating p62 and TOM20 expression.

CONCLUSION

This study suggested that TPSP2 could be a promising candidate for addressing obesity-related metabolic disorders by targeting mitochondrial quality control mechanisms.

Effects of electron beam irradiation on microbial load, physicochemical properties, sensory quality, stability of active components, and antioxidant activity of Platycodon grandiflorum (Jacq.) A. DC

Platycodon grandiflorum (Jacq.) A. DC. (PG) is an edible and medicinal plant. This study aimed to investigate the potential of electron beam (EB) irradiation for preserving PG. EB irradiation at doses of 2-8 kGy were applied to PG, and the effects on microbial content, sensory qualities, chemical qualities, and EB penetration were examined. Results showed that irradiation with 6 kGy effectively maintained the microbiological quality of PG when packing thickness was ≤6.3 cm during a 360-day storage period. The physicochemical properties, color, active ingredient contents, and antioxidant capacities of PG remained unaffected. However, total flavonoid and platycodin D (PD) content exhibited a non-dose-dependent alteration. The use of electronic nose analysis successfully differentiated the odor of EB irradiated PG samples from non-irradiated ones. Fingerprint analysis also indicated no significant impact of EB irradiation on PG quality. These findings suggest that EB treatment could be a valuable approach for extending the shelf life of PG.

Effect of γ-irradiation combined with enzymatic modification on the physicochemical properties of defatted rice bran dietary fiber

This study comprehensively examines how combining γ-irradiation and enzymatic modification influences the microstructure and physicochemical properties of dietary fiber (DF) obtained from defatted rice bran. The resulting yields of soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were measured at 13.38 ± 0.40 g/100 g and 52.19 ± 0.97 g/100 g, respectively. The modifications led to a diminish in particle size, an increase in specific surface area, and an improvement in water-holding capacity, oil-holding capacity, swelling capacity, glucose adsorption capacity, and cholesterol adsorption capacity. Furthermore, the modified DF exhibited enhanced anti-digestive properties and probiotic activity. Cluster and principal component analysis results revealed that the modified SDF exhibited superior functional properties. Correlation analysis indicated a noticeable relationship between the monosaccharide composition of DF and its functional characteristics. These findings suggest that γ-irradiation combined with enzymatic modification represents a viable approach for enhancing the quality of rice bran DF.

Effects of ultrasonic degradation on physicochemical and antioxidant properties of Gleditsia sinensis seed polysaccharides

In this study, two degraded polysaccharides from Gleditsia sinensis seed were obtained under ultrasonic power treatments of 300 and 450 W. The physicochemical properties, structural characteristics, and antioxidant activities of the degraded and undegraded polysaccharides were studied and compared. Ion exchange chromatography and methylation analysis showed that the polysaccharides had similar basic structural features and were composed of the same monosaccharide units before and after degradation, but the ultrasonic treatment increased the total monosaccharide content and changed the Mannose/Galactose value. Furthermore, with the increase in the ultrasonic power, the molecular weight and intrinsic viscosity of polysaccharides decreased, and the micromorphology became looser. The scavenging capacities for 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radicals and the reducing ability were significantly increased by the ultrasonic treatment. In conclusion, ultrasonic treatment may be an effective way to improve the antioxidant activities of polysaccharides from G. sinensis seed, and further studies on its antioxidant mechanism are still needed.

In vitro simulated digestion and fermentation behaviors of polysaccharides from Pleurotus cornucopiae and their impact on the gut microbiota

This study investigated the physicochemical characteristics and fermentative behavior between original polysaccharides (PCPs) and polysaccharides extracted after microwave cooking (MPCPs) from Pleurotus cornucopiae during simulated digestion and fecal fermentation. The results revealed notable physicochemical differences between of PCPs and MPCPs. MPCPs exhibited a higher total carbohydrate content, with an increased proportion of glucose. Additionally, MPCPs showed a lower molecular weight (MW) and, a blue shift in Fourier transform infrared spectroscopy (FT-IR). Digestion has a minimal effect on the physicochemical and structural characteristics of PCPs and MPCPs. Within the first 6 h of fermentation, the gut microbiota showed significantly higher utilization of MPCPs. However, PCPs were consumed faster and surpassed MPCPs later. After 24 h, both PCPs and MPCPs were degraded and utilized by the gut microbiota, showing an increased abundance of Firmicutes and Bacteroidota. PCPs excelled in promoting beneficial gut microbiota, such as Phascolarctobacterium, Megamonas, and Bacteroides. Conversely, MPCPs demonstrated a stronger ability to inhibit the growth of harmful opportunistic pathogenic gut microbiota, such as Fusobacterium and Parasutterella. In addition, the content of acetic, propionic, and butyric acids increased significantly in both PCPs and MPCPs. These findings highlight the potential of Pleurotus cornucopiae polysaccharides as prebiotics for intestinal homeostasis.

Structural characterization of a novel polysaccharide from Tremella fuciformis and its interaction with gut microbiota

BACKGROUND

Because of their diverse biological activities, polysaccharides derived from Tremella fuciformis have received growing attention. This study aimed to investigate the structural characterization of a purified polysaccharide (designated as PTP-3a) derived from T. fuciformis and explore its interaction with gut microbiota in vitro.

RESULTS

The findings revealed that PTP-3a had a molecular weight of 1.22 × 103 kDa and consisted of fucose, glucose, xylose, mannose and glucuronic acid in a molar ratio of 0.271:0.016:0.275:0.400:0.038. The primary linkage types identified in PTP-3a were 1,3-linked-manp, 1,4-linked-xylp and 1,2,3-linked-fucp, with corresponding ratios of 0.215:0.161:0.15. In addition, PTP-3a demonstrated notable thermal stability and exhibited a triple-helical structure. Moreover, following in vitro fermentation for 48 h, PTP-3a was efficiently utilized, resulting in a reduction in carbohydrate levels, the production of short-chain fatty acids (SCFAs) and pH adjustment. Furthermore, during in vitro fecal microbial fermentation, PTP-3a decreased the relative abundance of Firmicutes while increasing the proportions of Bacteroidetes and Proteobacteria, resulting in a significantly reduced Firmicutes/Bacteroidetes ratio. Additionally, PTP-3a stimulated the growth of beneficial bacteria such as Parabacteroides merdae, Gordonibacter pamelaeae, Bifidobacterium pseudolongum and Parabacteroides distasonis. Importantly, a strong correlation was observed between the production of SCFAs and specific microorganisms.

CONCLUSION

These findings suggested that PTP-3a has potential as a prebiotic for modulating the gut microbiota. © 2024 Society of Chemical Industry.

Structural characterization and hypoglycemic effect of polysaccharides of Polygonatum sibiricum

Polygonatum sibiricum polysaccharide (PSP) was extracted and purified from raw material obtained from P. sibiricum. The structural features of PSP were investigated by Congo red, circular dichroism spectrum, high-performance gel permeation chromatography, scanning electron microscope, atomic force microscope, ultraviolet spectroscopy, and Fourier transform infrared spectroscopy analysis. In vitro simulations were conducted to investigate the kinetics of PSP enzyme inhibition. Moreover, a type II diabetes mouse model (T2DM) with streptozotocin-induced insulin resistance was established, and the indexes of lipid quadruple, insulin resistance index, oral glucose tolerance (OGTT), organ index, and pancreatic morphology of model mice were measured. The results showed that PSP mainly consists of monosaccharides, such as mannose, glucose, galactose, xylose, and arabinose. It also has a β-glycosidic bond of a pyranose ring and an irregular reticulated aggregated structure with a triple helix. In vitro enzyme inhibition assays revealed that PSP acts as a reversible competitive inhibitor of α-glucosidase and α-amylase. Furthermore, PSP was found to reduce insulin resistance index, increase OGTT and serum insulin levels, decrease free fatty acid content to improve lipid metabolism, and lower glycated serum protein content to enhance glucose metabolism in T2DM mice, thereby leading to a reduction in blood glucose concentration. Additionally, PSP exhibited reparative effects on the damaged liver tissue cells and pancreatic tissue in T2DM mice. The experiment results provide a preliminary basis for the therapeutic mechanism of PSP about type II diabetes and a theoretical reference for application in food and pharmaceutical development.

Study on the physicochemical properties and antioxidant activities of Flammulina velutipes polysaccharide under controllable ultrasonic degradation based on artificial neural network

The polysaccharide fraction (FVP2) with molecular weight of 1525.09 kDa and intrinsic viscosity of 3.43 dL/g was isolated and purified from Flammulina velutipes (F. velutipes), and the ultrasonic degradation model of FVP2 was established to predict the molecular weight and intrinsic viscosity at the same time based on artificial neural network. FVP2U1 (1149.11 kDa, 1.78 dL/g), FVP2U2 (618.91 kDa, 1.19 dL/g) and FVP2U3 (597.35 kDa, 0.48 dL/g) with different molecular weights or viscosity were produced by this model to explore the effect of ultrasound on the physicochemical properties and antioxidant activity of FVP2. The results showed that ultrasonic treatment did not change the types of characteristic functional groups, monosaccharide composition and glycosidic bond of FVP2, but changed the chemical composition ratio and the degree of polymerization. Under ultrasonic treatment, the intrinsic viscosity of FVP2 still decreased significantly when the molecular weight did not decrease. Compared to other components subjected to ultrasonic degradation, FVP2U1 demonstrated higher molecular weight and viscoelasticity, while exhibiting lower antioxidant activity. In the case of no significant difference in molecular weight and monosaccharide composition, FVP2U3 with lower intrinsic viscosity has stronger hydration ability, higher crystallization index, lower viscoelasticity and stronger antioxidant capacity than FVP2U2.

Preparation of low molecular weight polysaccharides from Tremella fuciformis by ultrasonic-assisted H2O2-Vc method: Structural characteristics, in vivo antioxidant activity and stress resistance

Different methods were used to degrade Tremella fuciformis polysaccharides (TFP) and prepare low molecular weight polysaccharides of Tremella fuciformis (TFLP) to improve their bioavailability. It was found that the TFLP prepared by ultrasonic-assisted H2O2-Vc method showed the highest level of antioxidant activity and stress resistance in C. elegans. The structural characteristics, in vivo antioxidant and stress resistance of TFLP-1 were evaluated after isolation and purification of TFLP, it was found that TFLP-1 was an acid polysaccharide with a molecular weight of 75770 Da, which mainly composed of mannose. Meanwhile, it could regulate the antioxidant activity and stress resistance in C. elegans by upregulating the transcription of fat-5, fat-7, acs-2, glp-1, hsf-1, hsp-1, mtl-1, nhr-49, skn-1 and sod-3 mRNA. The improvement effects were closely related to the significant regulation of galactose metabolism, alpha linolenic acid metabolism, and pantothenate and CoA biosynthesis metabolic pathways. These results provided insights into the high value application of Tremella fuciformis in the food industry and the development of antioxidant related functional foods.

Effect of in vitro simulated digestion and fecal fermentation on Boletus auripes polysaccharide characteristics and intestinal flora

Boletus auripes is edible and medicinal boletus mushrooms rich in diverse nutrients and bioactive compounds, of which indigestible dietary polysaccharides are the most abundant compounds involved the regulation of gut microbes. However, the physicochemical, digestive, and fermentation characteristics of Boletus auripes polysaccharide (BAP) are not well studied. This study aimed to investigate the influence of different digestive stages on BAP's physicochemical characteristics and biological activities, and its effect on intestinal flora. We found that mannose (0.23 %), glucose (0.31 %), galactose (0.17 %), and fucose (0.19 %) were the main monosaccharides of BAP, with a high-molecular-weight (Mw) and a low-Mw fraction of 2084.83 and 62.93 kDa, respectively. During the course of digestion, there were slight alterations in the chemical composition, monosaccharide composition, and Mw of BAP. Despite these changes, the fundamental structural features of BAP remained largely unaffected. Moreover, the antioxidant and hypoglycemic activities of BAP were weakened under simulated saliva-gastrointestinal digestion. However, gut microbiota decomposed and utilized BAP to generate various short-chain fatty acids during fermentation, which decreased the pH of fecal cultures. Meanwhile, BAP modulated the gut microbiota composition and increased the relative abundance of Bacteroidetes. These findings suggest that BAP have potential for maintaining intestinal health and protecting against interrelated diseases.

Stabilization Activity of Kelp Extract in Ethylene-Propylene Rubber as Safe Packaging Material

This paper presents the stabilization effects of the solid extract of kelp (Ascophyllum nodosum) on an engineering elastomer, ethylene-propylene copolymer (EPR), which may be used as packaging material. Progressive increase in additive loadings (0.5, 1, and 2 phr) increases the oxidation induction time for thermally aged rubber at 190 °C from 10 min to 30 min for pristine material and modified polymer by adding 2 phr protection powder. When the studied polymer is γ-irradiated at 50 and 100 kGy, the onset oxidation temperatures increase as a result of blocking the oxidation reactivity of free radicals. The stabilization effect occurs through the activity of alginic acid, which is one of the main active components associated with alginates. The accelerated degradation caused by γ-exposure advances more slowly when the kelp extract is present. The OOT value for the oxidation of EPR samples increases from 130 °C to 165 °C after the γ-irradiation of pristine and modified (2 phr of kelp powder) EPR, respectively. The altered oxidation state of EPR samples by the action of γ-rays in saline serum is faster in neat polymer than in stabilized material. When the probes are placed in physiological serum and irradiated at 25 kGy, the OOT value for neat EPR (145 °C) is much lower than the homologous value for the polymer samples protected by kelp extract (153 °C for the concentration of 0.5 phr, 166 °C for the concentration of 1 phr, and 185 °C for the concentration of 2 phr).