Global research trend and hotspot in the low FODMAP diet: a bibliometric analysis.

BACKGROUND: According to national guidelines, a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) is a second-line therapy option for irritable bowel syndrome (IBS) and improves functional intestinal symptoms. Numerous noteworthy results have been published in this field over the past fifteen years. This study aims to analyze the global research trend and hotspot of the low FODMAP diet research, and provide a comprehensive perspective and direction for researchers. METHODS: The Science Citation Index-Expanded of the Web of Science Core Collection (WoSCC) was used to identify low FODMAP diet-related articles and reviews. Three bibliometric programs (CiteSpace, VOSviewer, Scimago Graphic) were utilized to analyze and visualize the annual publications, authors, countries, institutions, journals, citations, and keywords. RESULTS: In total, 843 documents related to the low FODMAP diet research were published in 227 journals by 3,343 authors in 1,233 institutions from 59 countries. The United States, which was the most engaged nation in international collaboration, had the largest annual production and the fastest growth. The most productive organization was Monash University, and the most fruitful researcher was Gibson PR. Nutrients ranked first in terms of the number of published documents. The article "A diet low in FODMAPs reduces symptoms of irritable bowel syndrome" (Halmos EP, 2014) received the most co-citations. Keywords that appear frequently in the literature mainly involve two main aspects: the clinical efficacy evaluation and mechanism exploration of the low FODMAP diet. The term "gut microbiota" stands out as the most prominent keyword among the burst keywords that have remained prevalent till date. CONCLUSION: The restriction stage of the low FODMAP diet is superior to other dietary therapies for IBS in terms of symptom response, but it has a negative impact on the abundance of gut Bifidobacteria and diet quality. Identification of biomarkers to predict response to the low FODMAP diet is of great interest and has become the current research hotspot.

Sensitive, precise fingerprint profiling for monosaccharide analysis of Bacillus Calmette-Guérin polysaccharide and nucleic acid isolates.

A sensitive and precise HPLC-DAD method with pre-column PMP derivatization was established and validated, for analyzing the polysaccharides in Bacillus Calmette-Guérin polysaccharide and nucleic acid (BCG-PSN) isolates, after acid hydrolysis. And the HPLC fingerprint profiling was used to analyze its monosaccharide composition. The monosaccharide concentration-peak area calibration curve was of good linearity (R2 > 0.99), over the range of 0.016-0.08 mg/mL for mannose or 0.24-1.20 mg/mL for glucose, with high recovery of 93-105 % for quality control samples. The intra-day RSD values of mannose and glucose concentration were less than 2.5 % and 2.1 %, respectively, and their inter-day RSD values were less than 4.3 % and 2.2 %, respectively, and remained stable for up to 14 days. This method also remained durable against changes in chromatographic parameters, but it's susceptible to the flow rate of mobile phase. Additionally, the method was applied to analyze the content of mannose and glucose in 22 batches BCG-PSN powder and 17 batches BCG-PSN injection. The results showed that the HPLC-DAD fingerprint spectra of all the BCG-PSN powder and BCG-PSN injection samples had a high degree of similarity, with the similar indexes up to 0.999 and 0.998, respectively. The HPLC-DAD method with pre-column PMP derivatization is highly rapid, effective, visual, and accurate for determination of monosaccharide contents. The validated method was successfully applied to the analysis of polysaccharide in both BCG-PSN powder and injection.

A Rapid and Accurate UHPLC Method for Determination of Monosaccharides in Polysaccharides of Different Sources of Radix Astragali and Its Immune Activity Analysis.

With the escalating demand for Astragalus polysaccharides products developed from Radix Astragali (RA), the necessity for quality control of polysaccharides in RA has become increasingly urgent. In this study, a specific method for the simultaneous determination of seven monosaccharides in polysaccharides extracted from Radix Astragali (RA) has been developed and validated using ultra-performance liquid chromatography equipped with an ultraviolet detector (UHPLC-UV) for the first time. The 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatizations were separated on a C18 column (Waters ACQUITYTM, Milfor, MA, USA, 1.8 µm, 2.1 × 100 mm) using gradient elution with a binary system of 5 mm ammonium formate (0.1% formic acid)-acetonitrile for 24 min. Additionally, seven monosaccharides showed good linear relationships (R2, 0.9971-0.9995), adequate precision (RSD < 4.21%), and high recoveries (RSD < 4.70%). The established method was used to analyze 109 batches of RA. Results showed that the Astragalus polysaccharides (APSs) mainly consist of mannose (Man), rhamnose (Rha), glucose (Glu), galactose (Gal), arabinose (Ara), xylose (Xyl); and fucose (Fuc); however, their composition was different among RA samples from different growth patterns, species, growth years, and origins, and the growth mode of RA and the age of wild-simulated RA can be accurately distinguished by principal component analysis (PCA). In addition, the immunological activity of APSs were also evaluated jointly by measurement of the NO release with RAW264.7, with the results showing that APSs have a promoting effect on the release of NO and exhibit a significant correlation with Man, Glu, Xyl, and Fuc contents. Accordingly, the new established monosaccharides analytical method and APS-immune activity determination in this study can provide a reference for quality evaluation and the establishment of quality standards for RA.

Relationship between dietary fiber content and prebiotic potential of polysaccharides from the seaweeds of the North west coast of India.

The macroalgae are a sustainable bioresource that can be harnessed for their functional food and nutraceutical applications. This study characterized the biochemical composition and bioactive potential of natural biological macromolecules, such as macroalgal polysaccharides extracted using a green, aqueous extraction process. The in-vitro antioxidant and antiglycemic activity of these polysaccharides were evaluated using model, free radical and antiglycemic compounds. The prebiotic potential of macroalgal polysaccharides were analysed based on their ability to promote the growth of two potential probiotic bacteria Lactobacillus acidophilus and L. bulgaricus and suppress the growth of enteric bacteria, Escherichia coli. Among the polysaccharides studied, the brown algal polysaccharide MPS8 MPS9 and MPS10 exhibited good antioxidant, antiglycemic and prebiotic activity. Based on infrared spectroscopy, the functional groups sulfation and carboxylation were identified in potential polysaccharides. The monosaccharide composition in the bioactive polysaccharides was determined using High Performance Anion Exchange Chromatography Pulse Amperometric detector (HPAEC-PAD). These bioactive polysaccharides were fractionated using ion exchange chromatography to purify it and further characterized using gel permeation chromatography and NMR spectroscopy. The results these polysaccharides are mainly composed of fucose and glucose which is due to the fucoidan and laminarin, respectively. Such macromolecules with high dietary fiber content and bioactivity are in global demand as functional food, nutraceutical and pharmaceutical formulations.

Selective impact of three homogenous polysaccharides with different structural characteristics from Grifola frondosa on human gut microbial composition and the structure-activity relationship.

Natural polysaccharides interact with gut microbes to enhance human well-being. Grifola frondosa is a polysaccharides-rich edible and medicinal mushroom. The prebiotic potential of G. frondosa polysaccharides has been explored in recent years, however, the relationship between their various structural features and prebiotic activities is poorly understood. In this study, three homogenous polysaccharides GFP10, GFP21 and GFP22 having different molecular weights (Mw), monosaccharide compositions and glycosidic linkages were purified from G. frondosa, and their effects on intestinal microbial composition were compared. GFP10 was a fucomannogalactan with an Mw of 23.0 kDa, and it selectively inhibited Enterobacter, while GFP21 was a fucomannogalactoglucan with an Mw of 18.6 kDa, and it stimulated Catenibacterium. GFP22 was a 4.9 kDa mannoglucan that selectively inhibited Klebsiella and boosted Bifidobacterium, Catenibacterium and Phascolarctobacterium, and prominently promoted the production of short-chain fatty acids (SCFAs). The selective modulation of gut microbiota by polysaccharides was structure-dependent. A relatively lower Mw and a high proportion of glycosidic linkages like T-Glcp, 1,3-Glcp, 1,3,6-Glcp and 1,4-Glcp might be more easily utilized to produce SCFAs and beneficial for the proliferation of Catenibacterium and Phascolarctobacterium. This research provided a valuable resource for further exploring the structure-activity relationship and prebiotic activity of G. frondosa polysaccharides.

Functional properties, structural characteristics, and anti-complementary activities of two degraded polysaccharides from strawberry fruits.

Two low-molecular-weight polysaccharides (DPSP50 and DPSP70) were obtained using hydrogen peroxide-vitamin C (H2O2-Vc) treatment at 50 °C and 70 °C, respectively. Both DPSP50 and DPSP70 comprised the same six monosaccharides in different ratios, and their molecular weights (Mws) were 640 kDa and 346 kDa, respectively. Functional properties analyses demonstrated that DPSP50 and DPSP70 each had an excellent water holding capacity, oil absorption capacity, and emulsion properties, as well as shear-thinning characteristics and viscoelastic properties. Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopic assays confirmed the existence of α-, ß-pyranose rings and the same six sugar residues in DPSP50 and DPSP70. The results of Congo red test, scanning electron microscopy (SEM), and X-ray diffraction (XRD) demonstrated that DPSP50 and DPSP70 did not contain triple-helix conformations, but were amorphous aggregates with flake-like shape and rough surface. Additionally, both DPSP50 and DPSP70 showed strong anti-complementary activities through the classical pathway and the alternative pathway. The results support the potential utility of these degraded polysaccharides from strawberry fruits in functional foods and medicines.

Homochiral light-sensitive metal-organic framework photoelectrochemical gated transistor for enantioselective discrimination of monosaccharides.

As pure antipodes may differ in biological interactions, pharmacology, and toxicity, discrimination of enantiomers is important in the pharmaceutical and agrochemical industries. Two major challenges in enantiomer determination are transducing and amplifying the distinct chiral-recognition signals. In this study, a light-sensitive organic photoelectrochemical transistor (OPECT) with homochiral character is developed for enantiomer discrimination. Demonstrated with the discrimination of glucose enantiomers, the photoelectrochemically active gate electrode is prepared by integrating Au nanoparticles (AuNPs) and a chiral Cu(II)-metal-organic framework (c-CuMOF) onto TiO2 nanotube arrays (TNT). The captured glucose enantiomers are oxidized to hydrogen peroxide (H2O2) by the oxidase-mimicking AuNPs-loaded c-CuMOF. Based on the confinement effect of the mesopocket structure of the c-CuMOF and the remarkable charge transfer ability of the 1D nanotubular architecture, variations in H2O2 yield are translated into significant changes in OPECT drain currents (ID) by inducing a catalytic precipitation reaction. Variations in ID confer a sensitive discrimination of glucose enantiomers with a limit of detection (LOD) of 0.07 µM for L-Glu and 0.05 µM for D-Glu. This enantiomer-driven gate electrode response strategy not only provides a new route for enantiomer identification, but also helps to understand the origin of the high stereoselectivity in living systems.

Physicochemical Characterization, Antioxidant and Anticancer Activity Evaluation of an Acidic Polysaccharide from Alpinia officinarum Hance.

AHP-3a, a triple-helix acidic polysaccharide isolated from Alpinia officinarum Hance, was evaluated for its anticancer and antioxidant activities. The physicochemical properties and structure of AHP-3a were investigated through gel permeation chromatography, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The weight-average molecular weight of AHP-3a was 484 kDa, with the molar percentages of GalA, Gal, Ara, Xyl, Rha, Glc, GlcA, and Fuc being 35.4%, 21.4%, 16.9%, 11.8%, 8.9%, 3.1%, 2.0%, and 0.5%, respectively. Based on the results of the monosaccharide composition analysis, methylation analysis, and NMR spectroscopy, the main chain of AHP-3a was presumed to consist of (1→4)-α-D-GalpA and (1→2)-α-L-Rhap residues, which is a pectic polysaccharide with homogalacturonan (HG) and rhamnogalacturonan-I (RG-I) structural domains containing side chains. In addition, the results of the antioxidant activity assay revealed that the ability of AHP-3a to scavenge DPPH, ABTS, and OH free radicals increased with an increase in its concentration. Moreover, according to the results from the EdU, wound healing, and Transwell assays, AHP-3a can control the proliferation, migration, and invasion of HepG2 and Huh7 hepatocellular carcinoma cells without causing any damage to healthy cells. Thus, AHP-3a may be a natural antioxidant and anticancer component.

Monosaccharide Analysis After One-Pot Derivatization Followed by Reverse-Phase Liquid Chromatography Separation and UV/Vis Detection.

Derivatization of monosaccharides with 1-phenyl-3-methyl-5-pyrazolone (PMP) introduces two chromophores per sugar molecule. Their separation on a superficially porous C18 reverse-phase column, using common liquid chromatography equipment, results in short analysis times (under 20 min) and high sensitivity (limit of quantitation 1 nmol). This method allows for complex monosaccharide mixtures to be separated and quantified using a reasonably simple and safe derivatization procedure.

Structure characterization and protective effect against UVB irradiation of polysaccharides isolated from the plateau plant Gentiana dahurica Fisch.

Gentiana dahurica Fisch. (G. dahurica) is one of the legitimate sources of Qinjiao in Traditional Chinese Medicine (TCM) and grows on high-altitude plateaus. Plants develop unique biochemical accumulations to resist plateau conditions, especially the strong UV irradiation. Thus, this study aimed to investigate the polysaccharide of G. dahurica (GDP), its structure and its activity against UVB irradiation. Four GDPs were isolated and two of them were subjected to structural elucidation. The results suggested that GDP-1 has 53.5 % Ara and 30.8 % GalA as its main monosaccharides, with a molecular weight (Mw) of 23 kDa; the GDP-2 has 33.9 % Ara and 48.5 % GalA, with a Mw of 82 kDa. Methylation and NMR spectroscopy analysis revealed that GDP-1 contains →5)-α-Araf-(1 â†’ 5)-α-Araf-(1 â†’ 3,5)-α-Araf-(1 â†’ 3,4)-α-GalpA-(6-OMe)-(1→ as the main chain, the branches of GalA (with esterification), and the terminal Ara; the GDP-2 contains →4)-α-GalpA-(1 â†’ 4)-α-GalpA-(6-OMe)-(1 â†’ 5)-α-Araf-(1 â†’ 3,5)-α-Araf-(1→ as the main chain, the branches of →5)-α-Araf-(1-5)-α-Araf, and the terminal GalA. Both GDP-1 and GDP-2 exhibited concentration-dependent antioxidant activity against DPPH, ABTS and hydroxyl radicals. Moreover, GDPs significantly attenuated the decreases in viability and proliferation of HaCaT cells after UVB irradiation. They can scavenge reactive oxygen species (ROS) and improve the activities of endogenous antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH). The potential mechanism explored by flow cytometry assays of cell apoptosis and cell cycle distribution suggested that GDPs exert protective effects against UVB irradiation by reducing ROS and attenuating S phase cell arrest. In brief, the GDP-1 and GDP-2 are α-1,3- and α-1,4- arabinogalacturonan, respectively. The high content of Ara could be attributed to biochemical accumulation in resisting to the plateau environment and to prevent UVB irradiation-related damage in cells. These findings provide insight into authentic medicinal herbs and the development of GDPs in the modern pharmaceutical and cosmetics industry.

Antioxidant and anti-aging activities of Longan crude and purified polysaccharide (LP-A) in nematode Caenorhabditis elegans.

Oxidative damage is an important cause of aging. The antioxidant and anti-aging activities of Longan polysaccharides, especially purified Longan polysaccharides, have not been thoroughly investigated. Therefore, this study aimed to investigate the antioxidant and anti-aging activities and mechanisms of crude polysaccharides and purified polysaccharides from Longan. A purified acidic Longan polysaccharide LP-A was separated from Longan crude polysaccharide LP. Subsequently, its structural characterization, anti-aging activity and mechanism were studied. The results showed that LP-A was an acidic heteropolysaccharide with an average molecular weight (Mw) of 4.606 × 104 Da which was composed of nine monosaccharides. The scavenging rate of ABTS free radical in vitro reached 99 %. In the nematode life experiment, 0.3 mg/mL LP group and LP-A group could prolong the average lifespan of nematodes by 9.31 % and 25.80 %, respectively. Under oxidative stress stimulation, LP-A group could prolong the survival time of nematodes by 69.57 %. In terms of mechanism, Longan polysaccharide can regulate insulin / insulin-like growth factor (IIS) signaling pathway, increase the activity of antioxidant enzymes, reduce lipid peroxidation, enhance the body's resistance to stress damage, and effectively prolong the lifespan of nematodes. In conclusion, LP-A has better anti-aging activity than crude polysaccharide LP, which has great potential for developing as an anti-aging drug.

Two novel polysaccharides from Huangshui: Purification, structure, and bioactivities.

In this study, the novel polysaccharides named HSP-0 M and HSP-0.1 M were successfully purified from Huangshui (HS), and their structural properties and bioactivities were investigated. Structural analysis revealed that HSP-0 M had a molecular weight of 493.87 kDa and was composed of arabinose, galactose, glucose, xylose, and mannose in a molar ratio of 1.48:1.09:26.52:1.33:1.00. On the other hand, HSP-0.1 M was made up of fructose, arabinose, galactose, glucose, xylose, mannose, ribose, galacturonic acid and glucuronic acid in a ratio of 2.67:26.00:29.10:36.83:16.22:30.53:1.00:1.43:3.64 with a molecular weight of 157.6 kDa. Methylated and 2D NMR analyses indicated that T-Glcp-(1 â†’ 4)-Glcp-(1 â†’ 2)-Glcp-(1 â†’ 3)-Glcp was the primary chain of HSP-0 M, and the backbone of HSP-0.1 M was made up of →3)-Galp-(1 â†’ 6)-Manp-(1 â†’ 3)-Glcp-(1 â†’ 6)-Glcp-(1 â†’ 2)-Manp-(1 â†’ 6)-Glcp-(1 â†’ 3)-Galp. Morphological research showed that both polysaccharides were homogeneous as well as exhibit a web-like structure and an irregular lamellar structure. Furthermore, HSP-0 M demonstrated the capacity to safeguard Lactococcus lactis from damage caused by low temperatures and freeze-drying, while HSP-0.1 M exhibited noteworthy antioxidant activity. These results established a theoretical foundation for the applications of HSPs in food products, cosmetics, and medicines.

Elucidation of antioxidant activities of intracellular and extracellular polysaccharides from Cordyceps militaris in vitro and their protective effects on ulcerative colitis in vivo.

In this study, we extracted the polysaccharides from C. militaris fruiting bodies (CFIPs), mycelial intracellular polysaccharides (CMIPs), and fermentation broth extracellular polysaccharides (CFEPs) to investigate their physicochemical properties, antioxidant capacities, and effects on oxazolone-induced zebrafish ulcerative colitis (UC). Our results revealed differences in monosaccharide composition and surface structure among CFIPs, CMIPs, and CFEPs. The molar ratios of glucose to mannose in CFIPs, glucose to xylose in CMIPs, and xylose to glucose in CFEPs were 7.57: 1.6, 7.26: 1.81, and 5.44: 2.98 respectively. Moreover, CFEPs exhibited significantly (p < 0.05) higher chemical antioxidant capacity compared to CMIPs and CFIPs. Surprisingly, CFEP treatment didn't show a significant effect in protecting against H2O2-induced oxidative damage in RAW 264.7 cells. After 3 d of treatment, the levels of ROS, MDA, and MPO in the CFIPs group exhibited a significant (p < 0.05) reduction by 37.82 %, 68.15 %, and 22.77 % respectively. Additionally, the ACP and AKP increased by 60.33 % and 96.99 %. Additionally, C. militaris polysaccharides (CMPs) were found to effectively improve UC by activating the MyD88/NF-κB signaling pathway in vivo. These findings confirm the distinct physicochemical properties of these three types of CMP and their potential for development into antioxidant-rich anti-inflammatory health foods.

Unlocking the potential of Opuntia species mucilage in chemistry.

Herein, we describe a detailed protocol to extract the mucilage from different species of the genus Opuntia spp. (i.e., Opuntia Ficus (OFi), Opuntia Dillenii (ODi) and Opuntia Robusta (ORo)). The extracted mucilage was characterized by NMR, FTIR-ATR, HPLC, and TGA. OFi was found to have the highest phenolic content, 7.84 ± 1.93 mg catechol/g mucilage. The mucilage from the three species were characterized by having a high content of monosaccharides, being mannose and glucose the most abundant components (ca. 48-73 % and 23-35 %, respectively). In the context of biomass revalorization, the mucilage was proven to serve as a reducing and stabilizing agent in the synthesis of gold nanoparticles (AuNP/mucilage). The synthesis was optimized with a mucilage concentration of 2 mg/mL using 12.5 µL of KAuCl4 and was carried out at 80 °C for 90 min. This protocol afforded spherical nanoparticles with an average size of 9.7 ± 4.0 nm that were stable for at least 14 days, as demonstrated by TEM. Synthesized AuNP/mucilage was evaluated as a plasmonic catalyst for the reduction of 4-nitrophenol as model reaction, showing a considerable enhancement in its kapp of 97 % under white light and a decrease of 24.8 % in its activation energy.

Structural Characterization and Immunoenhancing Properties of Polysaccharide CPTM-P1 from Taxus media.

Polysaccharides extracted from Taxus media hrough an aqueous method were further refined by removing proteins via the Sevag technique and purified by dialysis. The separation of these polysaccharides was accomplished using a DEAE-cellulose chromatog-raphy column, yielding two distinct fractions, named CPTM-P1 and CPTM-P2. Notably, CPTM-P1 emerged as the primary polysaccharide component within Taxus media. Consequently, a comprehensive analysis focusing exclusively on CPTM-P1 was undertaken. The molecular weight of CPTM-P1 was established through gel permeation chromatography (GPC), and its monosaccharide composition was deciphered using HPLC-MS. The structure was further elucidated through nuclear magnetic resonance (NMR) spectroscopy. The molecular weight of CPTM-P1 was determined to be 968.7 kDa. The monosaccharide composition consisted of galactose (Gal), arabinose (Ara), galacturonic acid (Gal-UA), glucose (Glc), rhamnose (Rha), xylose (Xyl), mannose (Man), fucose (Fuc), glucuronic acid (Glc-UA), and ribose (Rib). The proportional distribution of these components was 30.53%, 22.00%, 5.63%, 11.67%, 11.93%, 1.69%, 8.50%, 1.23%, 5.63%, and 1.17%, respectively. This confirmed CPTM-P1 as an acidic heteropolysaccharide with a glycuronic acid backbone. Moreover, CPTM-P1 showed immunoenhancing properties, effectively augmenting the secretion of nitric oxide and cytokines (TNF-α, IL-1ß, and IL-6). Additionally, it significantly enhances the phagocytic capacity of RAW264.7 cells. These findings underscore the potential application of these polysaccharides in functional foods and pharmaceuticals, providing a solid scientific basis for further exploration and utilization of Taxus media polysaccharides.

Efficient degradation and enhanced α-glucosidase inhibitory activity of apricot polysaccharides through non-thermal plasma assisted non-metallic Fenton reaction.

Dielectric barrier discharge (DBD) was a commonly used non-thermal plasma (CP) technology. This paper aimed to enhance the biological activity of apricot polysaccharides (AP) by using dielectric barrier discharge (DBD-CP) assisted H2O2-VC Fenton reaction for degradation. The degradation conditions were optimized through response surface methodology. The molecular weight (Mw) of degraded apricot polysaccharides (DAP) was 19.71 kDa, which was 7.25 % of AP. The inhibition rate of DAP (2 mg/mL) was 82.8 ± 3.27 %, which was 106.87 % higher than that of AP. DBD-CP/H2O2-VC degradation changed the monosaccharide composition of AP and improved the linearity of polysaccharide chains. In addition, a novel apricot polysaccharide DAP-2 with a Mw of only 6.60 kDa was isolated from DAP. The repeating units of the main chain of DAP-2 were →4)-α-D-GalpA-(1 →, the branch chain was mainly composed of α-D-GalpA-(1 â†’ 2)-α-L-Rhap-(1→ connected to O-3 position →3,4)-α-D-GalpA-(1→. The complex structure formed by the combination of DAP-2 and α-glucosidase was stable. DAP-2 had a higher α-glucosidase binding ability than the acarbose. These results suggested that DAP-2 had the potential to be developed as a potential hypoglycemic functional food and drug.

Chemical characterization of polysaccharides from Gracilaria gracilis from Bizerte (Tunisia).

Polysaccharides were extracted from Gracilaria gracilis collected from Manzel Jemil Lake in Bizerte Tunisia, with two different solvents (water and NaOH 0.3 M). Different assays were performed on samples (total sugars, neutral sugars, uronic acids, anhydrogalactose, proteins, sulphates, pyruvates), followed by high performance anion-exchange chromatography (HPAEC) to observe the monosaccharide composition, high pressure size exclusion chromatography with multi-angle laser light scattering (HPSEC-MALS) to obtain the molecular mass, Fourier transform infrared spectroscopy (FTIR), and 1D and 2D nuclear magnetic resonance (NMR) to access to structural data. Results have shown that the polysaccharide extracted from Gracilaria gracilis collected from Manzel Jemil Lake in Bizerte Tunisia, is of agar type but with high molecular mass and some original structural features. Hence, the sample was found to contain 9 % of pyruvate groups and is partly sulphated at the C4 of ß-d-galactose and methylated on C2 of anhydro-α-l-galactose. The polymer from G. gracilis from Bizerte thus presents a never described structure that could be interesting for further rheological or biological activities applications.

Inorganic arsenic in seaweed: a fast HPLC-ICP-MS method without coelution of arsenosugars.

Seaweed is becoming increasingly popular in the Western diet as consumers opt for more sustainable food sources. However, seaweed is known to accumulate high levels of arsenic-which may be in the form of carcinogenic inorganic arsenic (iAs). Here we propose a fast method for the routine measurement of iAs in seaweed using HPLC-ICP-MS without coelution of arsenosugars that may complicate quantification. The developed method was optimised using design of experiments (DOE) and tested on a range of reference materials including TORT-3 (0.36 ± 0.03 mg kg-1), DORM-5 (0.02 ± 0.003 mg kg-1), and DOLT-5 (0.07 ± 0.007 mg kg-1). The use of nitric acid in the extraction solution allowed for the successful removal of interferences from arsenosugars by causing degradation to an unretained arsenosugar species, and a recovery of 99 ± 9% was obtained for iAs in Hijiki 7405-b when compared with the certified value. The method was found to be suitable for high-throughput analysis of iAs in a range of food and feed matrices including Asparagopsis taxiformis seaweed, grass silage, and insect proteins, and offers a cost-effective, fast, and robust option for routine analysis that requires minimal sample preparation. The method may be limited with regards to the quantification of dimethylarsenate (DMA) in seaweed, as the acidic extraction may lead to overestimation of this analyte by causing degradation of lipid species that are typically more abundant in seaweed than other marine matrices (i.e. arsenophospholipids). However, the concentrations of DMA quantified using this method may provide a better estimation with regard to exposure after ingestion and subsequent digestion of seaweed.

Effect of extraction method on the structure and bioactivity of polysaccharides from activated sludge.

Resource recovery is a pivotal facet of waste activated sludge treatment, particularly within the framework of carbon neutrality and the circular economy. Polysaccharides are emerging as a valuable resource from waste activated sludge, and the choice of extraction method affects the properties of the polysaccharides, which is of utmost importance for subsequent application. This investigation examined the effects of six extraction methods (i.e., acidic, alkaline, ultrasonication, hot-water, microwave, and electric treatments) on the yield, chemical composition, structural characteristics, and bioactivities of polysaccharides extracted from sludge. For each extraction method, two operational parameters, namely the treatment time and strength (e.g., the acid and alkali concentration), were initially optimized in terms of the polysaccharide yield. The polysaccharide yield varied from 1.03 ± 0.12 % to 5.34 ± 0.10 % adopting the extraction methods under optimized conditions, and the alkaline extraction method had the highest yield of polysaccharides with a treatment time of 120 min and NaOH concentration of 1 %. At least one polysaccharide fraction was successfully purified from the crude polysaccharide of each extraction method. The compositions and structures of these fractions, including carbohydrate, protein, sulfate, uronic acid contents, and monosaccharide compositions, were determined. Carbohydrate was the dominant component, with the hot-water-2 fraction having the highest carbohydrate content (77.90 % ± 2.02 %). Monosaccharides in the polysaccharides were measured, with mannose, rhamnose, glucose, and xylose being found in all fractions, whereas ribose was exclusively found in the acid-1 fraction. The molecular weights of these fractions ranged between 1.60 × 104 Da and 7.11 × 106 Da. Furthermore, the bioactivities of the polysaccharides, encompassing five anti-oxidant and three anti-coagulant properties, were assessed, with the ultrasonication-1 fraction having superior performance in seven of the assays. Finally, the association among the fractions in terms of composition and bioactivity was assessed adopting cluster analysis and regression methods. The findings underscore the effect of the extraction method on the properties of polysaccharides extracted from sludge, thereby providing valuable insights for the prospective applications of polysaccharides.

Effects of different extraction methods on the structural and biological properties of Hericium coralloides polysaccharides.

In current study, polysaccharides from Hericium coralloides were extracted by heat reflux, acid-assisted, alkali-assisted, enzyme-assisted, ultrasonic-assisted, cold water, pressurized hot water, hydrogen peroxide/ascorbic acid system and acid-chlorite delignification methods, which were named as HRE-P, ACE-P, AAE-P, EAE-P, UAE-P, CWE-P, PHE-P, HAE-P, and ACD-P, respectively. Their physicochemical properties, structural characteristics, and antioxidant activities were investigated and compared. Experimental outcomes indicated notable variations in the extraction yields, chemical compositions, monosaccharide constituents and molecular weights of the obtained nine polysaccharides. HRE-P demonstrated the highest activity against ABTS and OH radicals, CWE-P against ABTS, DPPH, and superoxide radicals, and UAE-P against DPPH radicals. In addition, UAE-P, CWE-P, and HAE-P exhibited better protective effects on L929 cells, when compared to the other obtained polysaccharides. Additionally, correlation analysis indicated that monosaccharide composition and total polyphenol content were two prominent variables influencing the bioactivity of H. coralloides polysaccharides.