Fate of chitin-glucan in the human gastrointestinal tract as studied in a dynamic gut simulator (SHIME®)

Extraction of chitin-glucan complex from shiitake (Lentinula edodes) fruiting bodies using natural deep eutectic solvents and its prebiotic potential

Chitin-glucan complex (CGC) is an emerging novel prebiotic with numerous physiological activities in amelioration of clinical manifestations. In the present work, natural deep eutectic solvent (NADES), ultrasonication, and submerged fermentation using probiotic microorganisms were deployed for the extraction of CGC from Shiitake fruiting bodies. CGC obtained through non-ultrasonication assisted fermentation employing Lactiplantibacillus plantarum exhibited maximum polysaccharide yield (27.86 ± 0.82 % w/w). However, based on antioxidant potential, NADES combination of urea: glycerol (1:1 M ratio) was selected for further characterization. The rheological behavior of CGC under optimized conditions showed shear thinning property in both 0.1 M NaCl and salt-free solution. FTIR, 1H-(1D), and 2D 1H1H Homonuclear NMR spectra displayed distinctive patterns associated with β-glycosidic linkage and β-d-glucopyranose sugar moiety. XRD profiles of CGC exhibited characteristic peaks at 2θ = 23°, 25°, and 28° with corresponding hkl values of (220), (101), and (130) lattice planes, respectively. Enhanced radical scavenging activities were noticed due to the triple helical structure and anionic nature of CGC. CGC exhibited potential prebiotic activity (prebiotic score 118-134 %) and short chain fatty acids liberation (maximum 9.99 ± 0.41 mM by Lactobacillus delbrueckii). Simulated static in-vitro digestion demonstrated that CGC withstands acidic environment of gastric phase, which indicated its suitability for use as a prebiotic in nutraceutical-enriched food products.

In vitro protein digestion and carbohydrate colon fermentation of microbial biomass samples from bacterial, filamentous fungus and yeast sources

This study evaluated the nutritional quality of different microbial biomass samples by assessing their protein digestibility and carbohydrate fermentability in the colon using in vitro methods. Four microbial samples were produced: one hydrogen-oxidizing bacterial strain (Nocardioides nitrophenolicus KGS-27), two strains of filamentous fungi (Rhizopus oligosporus and Paecilomyces variotii), and one yeast strain (Rhodotorula babjevae). The microorganisms were grown in bioreactors, harvested and dried before analysis. The commercial fungal product Quorn was used as a reference. The protein digestibility of the microbial samples was analysed using the INFOGEST in vitro model, followed by quantification of N-terminal amine groups. An in vitro faecal fermentation experiment was also performed to evaluate the degradation of carbohydrates in microbial biomass samples and formation of short-chain fatty acids (SCFA). The fungal biomass samples had higher protein hydrolysis (60-75 %) than the bacterial sample (12 %) and Quorn (45 %), while the yeast biomass had the highest protein digestibility (85 %). Heat-treatment of the biomass significantly reduced its protein digestibility. Total dietary fibre (DF) content of fungal biomass was 31 - 43 %(DW), mostly insoluble, whereas the bacterial biomass contained mainly soluble DF (total DF: 25.7 %, of which 23.5 % were soluble and 2.2 % insoluble). After 24 h of colonic in vitro fermentation, SCFA production from the biomass of Paecilomyces, Quorn and Rhodotorula was similar to that of wheat bran, while 17 % and 32 % less SCFA were produced from the biomass of Rhizopus and the bacterial strain, respectively. Further studies are needed to clarify the reasons for the observed differences in protein digestibility and DF fermentability, especially regarding the cell wall structures and role of post-processing.

Colonic in vitro fermentation of mycoprotein promotes shifts in gut microbiota, with enrichment of Bacteroides species

Mycoprotein is a fungal-derived ingredient used for meat alternative products whose fungal cell walls are rich in dietary fibre (β-glucans and chitin) and defines its structure. Several health benefits have been reported after mycoprotein consumption, however, little is known about the impact of mycoprotein fermentation on the gut microbiota. This study aims to identify changes in microbiome composition and microbial metabolites during colonic fermentation of mycoprotein following simulated upper gastrointestinal digestion. Changes in microbial populations and metabolites produced by the fermentation of mycoprotein fibre were investigated and compared to a plant (oat bran) and an animal (chicken) comparator. In this model fermentation system, mycoprotein and oat showed different but marked changes in the microbial population compared to chicken, which showed minimal differentiation. In particular, Bacteroides species known for degrading β-glucans were found in abundance following fermentation of mycoprotein fibre. Mycoprotein fermentation resulted in short-chain fatty acid production comparable with oat and chicken at 72 h. Significantly higher branched-chain amino acids were observed following chicken fermentation. This study suggests that the colonic fermentation of mycoprotein can promote changes in the colonic microbial profile. These results highlight the impact that the unique structure of mycoprotein can have on digestive processes and the gut microbiota.

Bioactive compounds and biological activity in edible insects: A review

New strategies to combat hunger are a current and urgent demand. The increase in population has generated a high demand for products and services that affect food production, cultivation areas, and climate. Viable and sustainable alternative sources have been sought to meet food quality requirements. In this context, edible insects are a good source of macro-nutrients, and bioactive compounds confer biological properties that improve their nutritional aspects and benefit human health. This review aims to present the benefits and contributions of edible insects from the point of view of the biological contribution of macronutrients, and bioactive compounds, as well as consider some anti-nutritional aspects reported in edible insects. It was found that insects possess most of the macronutrients necessary for human life and are rich in bioactive compounds commonly found in plants. These bioactive compounds can vary significantly depending on the developmental stage, diet, and species of edible insects. However, they also contain phytochemicals in which anti-nutrients predominate, which can adversely affect humans with allergenic reactions or reduced nutrient viability when consumed in high amounts or for prolonged periods. Hydrocyanide, oxalates, soluble oxalate, and phytate are the most studied anti-nutrients. However, the doses at which they occur are far below the limits in foods. In addition, anti-nutrient levels decrease significantly in processing, such as oven-drying and defatting methods. However, there are few studies, so more trials are needed to avoid generalizing. Therefore, edible insects can be considered complete food.

Gut microbiota response to in vitro transit time variation is mediated by microbial growth rates, nutrient use efficiency and adaptation to in vivo transit time

BACKGROUND

Transit time is an important modulator of the human gut microbiome. The inability to modify transit time as the sole variable hampers mechanistic in vivo microbiome research. We singled out gut transit time in an unprecedented in vitro approach by subjecting faecal microbial communities from six individuals with either short, medium or long in vivo transit times, to three different colonic transit times of 21, 32 and 63 h in the validated human gut in vitro model, SHIME.

RESULTS

Transit time was identified as the single most important driver of microbial cell concentrations (52%), metabolic activity (45%) and quantitative (24%) and proportional (22%) community composition. Deceleration of transit was characterised by a significant decrease of specific Bifidobacterium and Veillonella spp. and increase of specific fibre degrading bacteria and nutrient specialists, such as Bacteroides, Prevotella, Ruminococcus, Bilophila and Akkermansia spp. These microbial communities reached a higher population density and net carbohydrate fermentation, leading to an increased SCFA production at longer transit times. In contrast, the carbohydrate-to-biomass production efficiency was increased at shorter transits, particularly in well-adapted faecal microbiomes from donors with short in vivo transit. Said adaptation was also reflected in the carbohydrate-to-SCFA conversion efficiency which varied with donor, but also colon region and SCFA chain length. A long transit time promoted propionate production, whereas butyrate production and butyrate producers were selectively enriched in the proximal colon at medium transit time.

CONCLUSION

Microbial growth rates and nutrient utilisation efficiency mediate the species-specific gut microbiota response to in vitro transit time variation, which is the main driver of in vitro microbial load, metabolism and community composition. Given the in vivo transit time variation within and between individuals, the personalisation of in vitro transit time based on in vivo data is required to accurately study intra- and inter-individual differences in gut microbiome structure, functionality and interactions with host and environmental modulators. Video Abstract.

Food biopolymer behaviors in the digestive tract: implications for nutrient delivery

Biopolymers are prevalent in both natural and processed foods, serving as thickeners, emulsifiers, and stabilizers. Although specific biopolymers are known to affect digestion, the mechanisms behind their influence on the nutrient absorption and bioavailability in processed foods are not yet fully understood. The aim of this review is to elucidate the complex interplay between biopolymers and their behavior in vivo, and to provide insights into the possible physiological consequences of their consumption. The colloidization process of biopolymer in various phases of digestion was analyzed and its impact on nutrition absorption and gastrointestinal tract was summarized. Furthermore, the review discusses the methodologies used to assess colloidization and emphasizes the need for more realistic models to overcome challenges in practical applications. By controlling macronutrient bioavailability using biopolymers, it is possible to enhance health benefits, such as improving gut health, aiding in weight management, and regulating blood sugar levels. The physiological effect of extracted biopolymers utilized in modern food structuring technology cannot be predicted solely based on their inherent functionality. It is essential to account for factors such as their initial consuming state and interactions with other food components to better understand the potential health benefits of biopolymers.

Interaction between β-glucans and gut microbiota: a comprehensive review

Gut microbiota (GMB) in humans plays a crucial role in health and diseases. Diet can regulate the composition and function of GMB which are associated with different human diseases. Dietary fibers can induce different health benefits through stimulation of beneficial GMB. β-glucans (BGs) as dietary fibers have gained much interest due to their various functional properties. They can have therapeutic roles on gut health based on modulation of GMB, intestinal fermentation, production of different metabolites, and so on. There is an increasing interest in food industries in commercial application of BG as a bioactive substance into food formulations. The aim of this review is considering the metabolizing of BGs by GMB, effects of BGs on the variation of GMB population, influence of BGs on the gut infections, prebiotic effects of BGs in the gut, in vivo and in vitro fermentation of BGs and effects of processing on BG fermentability.

Chitosan and Chitooligosaccharide: The Promising Non-Plant-Derived Prebiotics with Multiple Biological Activities

Biodegradable chitin is the second-most abundant natural polysaccharide, widely existing in the exoskeletons of crabs, shrimps, insects, and the cell walls of fungi. Chitosan and chitooligosaccharide (COS, also named chitosan oligosaccharide) are the two most important deacetylated derivatives of chitin. Compared with chitin, chitosan and COS not only have more satisfactory physicochemical properties but also exhibit additional biological activities, which cause them to be widely applied in the fields of food, medicine, and agriculture. Additionally, due to their significant ability to improve gut microbiota, chitosan and COS are deemed prospective prebiotics. Here, we introduced the production, physicochemical properties, applications, and pharmacokinetic characteristics of chitosan and COS. Furthermore, we summarized the latest research on their antioxidant, anti-inflammatory, and antimicrobial activities. Research progress on the prebiotic functions of chitosan and COS is particularly reviewed. We creatively analyzed and discussed the mechanisms and correlations underlying these activities of chitosan and COS and their physicochemical properties. Our work enriched people's understanding of these non-plant-derived prebiotics. Based on this review, the future directions of research on chitosan and COS are explored. Collectively, optimizing the production technology of chitin derivatives and enriching understanding of their biological functions will shed more light on their capability to improve human health.

Chitin-glucan supplementation improved postprandial metabolism and altered gut microbiota in subjects at cardiometabolic risk in a randomized trial

Chitin-glucan (CG), an insoluble dietary fiber, has been shown to improve cardiometabolic disorders associated with obesity in mice. Its effects in healthy subjects has recently been studied, revealing its interaction with the gut microbiota. In this double-blind, randomized, cross-over, twice 3-week exploratory study, we investigated the impacts of CG on the cardiometabolic profile and gut microbiota composition and functions in 15 subjects at cardiometabolic risk. They consumed as a supplement 4.5 g of CG daily or maltodextrin as control. Before and after interventions, fasting and postprandial metabolic parameters and exhaled gases (hydrogen [H2] and methane [CH4]) were evaluated. Gut microbiota composition (16S rRNA gene sequencing analysis), fecal concentrations of bile acids, long- and short-chain fatty acids (LCFA, SCFA), zonulin, calprotectin and lipopolysaccharide binding protein (LBP) were analyzed. Compared to control, CG supplementation increased exhaled H2 following an enriched-fiber breakfast ingestion and decreased postprandial glycemia and triglyceridemia response to a standardized test meal challenge served at lunch. Of note, the decrease in postprandial glycemia was only observed in subjects with higher exhaled H2, assessed upon lactulose breath test performed at inclusion. CG decreased a family belonging to Actinobacteria phylum and increased 3 bacterial taxa: Erysipelotrichaceae UCG.003, Ruminococcaceae UCG.005 and Eubacterium ventriosum group. Fecal metabolites, inflammatory and intestinal permeability markers did not differ between groups. In conclusion, we showed that CG supplementation modified the gut microbiota composition and improved postprandial glycemic response, an early determinant of cardiometabolic risk. Our results also suggest breath H2 production as a non-invasive parameter of interest for predicting the effectiveness of dietary fiber intervention.

Physicochemical characterization, adsorption function and prebiotic effect of chitin-glucan complex from mushroom Coprinus comatus

Chitin-glucan complex (CGC) is a novel insoluble dietary fiber with multiple physiological activities. In this work, CGC was extracted from the fruiting body of Coprinus comatus and its physicochemical properties and prebiotic effects were investigated. The results indicated that CGC consisted of glucosamine and glucose in a molar ratio of 67: 33 with degree of acetylation of 61.91% and crystallinity index of 25.40%. The maximum degradation temperature was determined to be 307.52 °C, and a woven fibrous structure was observed by scanning electron microscopy. CGC exhibited higher oil-holding capacity, water-holding capacity and nitrite ion adsorption capacity than commercial chitin, and showed potential prebiotic effects. Compared with control and commercial chitin, CGC significantly (P < 0.05) increased the concentration of propionic and butyric acids. These results suggested that CGC from C. comatus was promising to be an alternative source of CGC products and used as a bioactive ingredient in functional foods.

Chitin-Glucan Complex Hydrogels: Optimization of Gel Formation and Demonstration of Drug Loading and Release Ability

Chitin-glucan complex (CGC) hydrogels were fabricated through a freeze-thaw procedure for biopolymer dissolution in NaOH 5 mol/L, followed by a dialysis step to promote gelation. Compared to a previously reported methodology that included four freeze-thaw cycles, reducing the number of cycles to one had no significant impact on the hydrogels' formation, as well as reducing the total freezing time from 48 to 18 h. The optimized CGC hydrogels exhibited a high and nearly spontaneous swelling ratio (2528 ± 68%) and a water retention capacity of 55 ± 3%, after 2 h incubation in water, at 37 °C. Upon loading with caffeine as a model drug, an enhancement of the mechanical and rheological properties of the hydrogels was achieved. In particular, the compressive modulus was improved from 23.0 ± 0.89 to 120.0 ± 61.64 kPa and the storage modulus increased from 149.9 ± 9.8 to 315.0 ± 76.7 kPa. Although the release profile of caffeine was similar in PBS and NaCl 0.9% solutions, the release rate was influenced by the solutions' pH and ionic strength, being faster in the NaCl solution. These results highlight the potential of CGC based hydrogels as promising structures to be used as drug delivery devices in biomedical applications.

In Vitro Study of Cricket Chitosan's Potential as a Prebiotic and a Promoter of Probiotic Microorganisms to Control Pathogenic Bacteria in the Human Gut

In this study, cricket chitosan was used as a prebiotic. Lactobacillus fermentum, Lactobacillus acidophilus, and Bifidobacterium adolescentis were identified as probiotic bacteria. Cricket chitin was deacetylated to chitosan and added to either De Man Rogosa and Sharpe or Salmonella/Shigella bacterial growth media at the rates of 1%, 5%, 10%, or 20% to obtain chitosan-supplemented media. The growth of the probiotic bacteria was monitored on chitosan-supplemented media after 6, 12, 24, and 48 h upon incubation at 37 °C. Growth of Salmonella typhi in the presence of probiotic bacteria in chitosan-supplemented media was evaluated under similar conditions to those of the growth of probiotic bacteria by measuring growth inhibition zones (in mm) around the bacterial colonies. All chitosan concentrations significantly increased the populations of probiotic bacteria and decreased the populations of pathogenic bacteria. During growth, there was a significant pH change in the media with all probiotic bacteria. Inhibition zones from probiotic bacteria growth supernatant against Salmonella typhi were most apparent at 16 mm and statistically significant in connection with a 10% chitosan concentration. This study suggests cricket-derived chitosan can function as a prebiotic, with an ability to eliminate pathogenic bacteria in the presence of probiotic bacteria.

Chitin Glucan Shifts Luminal and Mucosal Microbial Communities, Improve Epithelial Barrier and Modulates Cytokine Production In Vitro

The human gut microbiota has been linked to the health status of the host. Modulation of human gut microbiota through pro- and prebiotic interventions has yielded promising results; however, the effect of novel prebiotics, such as chitin-glucan, on gut microbiota-host interplay is still not fully characterized. We assessed the effect of chitin-glucan (CG) and chitin-glucan plus Bifidobacterium breve (CGB) on human gut microbiota from the luminal and mucosal environments in vitro. Further, we tested the effect of filter-sterilized fecal supernatants from CG and CGB fermentation for protective effects on inflammation-induced barrier disruption and cytokine production using a co-culture of enterocytes and macrophage-like cells. Overall, CG and CGB promote health-beneficial short-chain fatty acid production and shift human gut microbiota composition, with a consistent effect increasing Roseburia spp. and butyrate producing-bacteria. In two of three donors, CG and CGB also stimulated Faecalibacterium prausniitzi. Specific colonization of B. breve was observed in the lumen and mucosal compartment; however, no synergy was detected for different endpoints when comparing CGB and CG. Both treatments included a significant improvement of inflammation-disrupted epithelial barrier and shifts on cytokine production, especially by consistent increase in the immunomodulatory cytokines IL10 and IL6.

In vitro gastrointestinal digestion and fermentation models and their applications in food carbohydrates

Food nutrients plays a crucial role in human health, especially in gastrointestinal (GI) health. The effect of food nutrients on human health mainly depends on the digestion and fermentation process in the GI tract. In vitro GI digestion and fermentation models had the advantages of reproducibility, simplicity, universality, and could integrally simulate the in vivo conditions to mimic oral, gastric, small intestinal and large intestinal digestive processes. They could not only predict the relationship among material composition, structure and digestive characteristics, but also evaluate the bioavailability of material components and the impact of digestive metabolites on GI health. This review systematicly summarized the current state of the in vitro simulation models, and made detailed descriptions for their applications, advantages and disadvantages, and specially their applications in food carbohydrates. In addition, it also provided the suggestions for the improvement of in vitro models and firstly proposed to establish a set of standardized methods of in vitro dynamic digestion and fermentation conditions for food carbohydrates, which were in order to further evaluate more effects of the nutrients on human health in future.

Noninvasive monitoring of fibre fermentation in healthy volunteers by analyzing breath volatile metabolites: lessons from the FiberTAG intervention study

The fermentation of dietary fibre (DF) leads to the production of bioactive metabolites, the most volatile ones being excreted in the breath. The aim of this study was to analyze the profile of exhaled breath volatile metabolites (BVM) and gastrointestinal symptoms in healthy volunteers after a single ingestion of maltodextrin (placebo) versus chitin-glucan (CG), an insoluble DF previously shown to be fermented into short-chain fatty acids (SCFA) by the human microbiota in vitro. Maltodextrin (4.5 g at day 0) or CG (4.5 g at day 2) were added to a standardized breakfast in fasting healthy volunteers (n = 15). BVM were measured using selected ion flow tube mass spectrometry (SIFT-MS) throughout the day. A single ingestion of 4.5 g CG did not induce significant gastrointestinal discomfort. Untargeted metabolomics analysis of breath highlighted that 13 MS-fragments (among 408 obtained from ionizations of breath) discriminated CG versus maltodextrin acute intake in the posprandial state. The targeted analysis revealed that CG increased exhaled butyrate and 5 other BVM - including the microbial metabolites 2,3-butanedione and 3-hydroxybutanone - with a peak observed 6 h after CG intake. Correlation analyses with fecal microbiota (Illumina 16S rRNA sequencing) spotlighted Mitsuokella as a potential genus responsible for the presence of butyric acid, triethylamine and 3-hydroxybutanone in the breath. In conclusion, measuring BMV in the breath reveals the microbial signature of the fermentation of DF after a single ingestion. This protocol allows to analyze the time-course of released bioactive metabolites that could be proposed as new biomarkers of DF fermentation, potentially linked to their biological properties. Trial registration: Clinical Trials NCT03494491. Registered 11 April 2018 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03494491.

In Vitro Studies Toward the Use of Chitin as Nutraceutical: Impact on the Intestinal Epithelium, Macrophages, and Microbiota

SCOPE

Chitin, the most abundant polysaccharide found in nature after cellulose, is known for its ability to support wound healing and to lower plasma-oxidized low-density lipoprotein (LDL) levels. Studies have also revealed immunomodulatory potential but contradicting results are often impossible to coalesce through usage of chitin of different or unknown physicochemical consistency. In addition, only a limited set of cellular models have been used to test the bioactivity of chitin.

METHODS AND RESULTS

Chitin is investigated with well-defined physicochemical consistency for its immunomodulatory potency using THP-1 macrophages, impact on intestinal epithelial barrier using Caco-2 cells, and fermentation by fecal-derived microbiota. Results show that chitin with a degree of acetylation (DA) of ≈83%, regardless of size, does not affect the intestinal epithelial barrier integrity. Large-sized chitin significantly increases acetic acid production by gut microbiota without altering the composition. Exposure of small-sized chitin to THP-1 macrophages lead to significantly increased secretion of IL-1β, IL-8, IL-10, and CXCL10 in a multi-receptor and clathrin-mediated endocytosis dependent manner.

CONCLUSIONS

These findings indicate that small-sized chitin does not harm the intestinal barrier nor affects SCFA secretion and microbiota composition, but does impact immune activity which could be beneficial to subjects in need of immune support or activation.

Metabolite profiling reveals the interaction of chitin-glucan with the gut microbiota

Dietary fibers are considered beneficial nutrients for health. Current data suggest that their interaction with the gut microbiota largely contributes to their physiological effects. In this context, chitin-glucan (CG) improves metabolic disorders associated with obesity in mice, but its effect on gut microbiota has never been evaluated in humans. This study explores the effect of a 3-week intervention with CG supplementation in healthy individuals on gut microbiota composition and bacterial metabolites. CG was given to healthy volunteers (n = 15) for three weeks as a supplement (4.5 g/day). Food diary, visual analog and Bristol stool form scales and a "quality of life" survey were analyzed. Among gut microbiota-derived metabolites, bile acids (BA), long- and short-chain fatty acids (LCFA, SCFA) profiling were assessed in stool samples. The gut microbiota (primary outcome) was analyzed by Illumina sequencing. A 3-week supplementation with CG is well tolerated in healthy humans. CG induces specific changes in the gut microbiota composition, with Eubacterium, Dorea and Roseburia genera showing the strongest regulation. In addition, CG increased bacterial metabolites in feces including butyric, iso-valeric, caproic and vaccenic acids. No major changes were observed for the fecal BA profile following CG intervention. In summary, our work reveals new potential bacterial genera and gut microbiota-derived metabolites characterizing the interaction between an insoluble dietary fiber -CG- and the gut microbiota.

Breast-milk derived potential probiotics as strategy for the management of childhood obesity

Obesity and overweight, and their concomitant metabolic diseases, emerge as one of the most severe health problems in the world. Prevention and management of obesity are proposed to begin early in childhood, when probiotics may have a role. The Simulator of the Human Intestinal Microbial Ecosystem (SHIME®), in a dynamic validated in vitro system able to simulate the different parts of the gastrointestinal tract, has proven to be useful in analyzing the human intestinal microbial community. L. plantarum 73a and B. animalis subsp. lactis INL1, two strains isolated from breast milk, were assayed in the SHIME® using the fecal microbiota of an obese child. L. plantarum 73a alone or in combination with B. animalis subsp. lactis INL1 demonstrated survival capacity in the SHIME® system. The administration of both strains increased the alpha diversity of the microbiota and reduced the levels of the phylum Proteobacteria. In particular, the genera Escherichia, Shigella, and Clostridium_sensu_stricto_1 were significantly reduced when both strains were administered. The increase of Proteobacteria phylum is generally associated with the microbiota of obese people. Escherichia and Shigellacan be involved in inflammation-dependent adiposity and insulin resistance. L. plantarum73a supplementation reduced ammonia production. L. plantarum 73a alone or in combination with B. animalis subsp. lactis INL1 are potential probiotic candidates for the management of infant obesity.

Green synthesis, characterization and biological evaluation of chitin glucan based zinc oxide nanoparticles and its curcumin conjugation

A well-organized, simplistic, and green route of chitin-glucan based zinc oxide nanoparticles (ChGC@ZnONPs) was synthesized using reducing and capping agent both in one as chitin-glucan complex (ChGC). Herein we report the bio-synthesis of Cur-ChGC@ZnONPs by the conjugation of curcumin (Cur) with ChGC@ZnONPs for the improvement of antioxidant and antibacterial activity. The synthesized nanoparticles were characterized by the UV-Visible (UV-Vis), particle size analyser, scanning electron microscope (SEM) with Energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscope (TEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). Structure analysis, shape and crystalline size of nanomaterials were confirmed by scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM). The particle size analyser showed the particle size of nanomaterials and stability. Crystalline nature of both ChGC@ZnONPs and Cur-ChGC@ZnONPs were confirmed by the XRD spectra and FT-IR spectrum was used to examine the functional groups of nanomaterials. The antioxidant potential of conjugated nanomaterials were estimated using a DPPH free radical scavenging assay and ABTS^+⁎ assay. This analysis showed that after loading of Cur, antioxidant activity increases. The antibacterial assessment of conjugated nanomaterials were tested by different microorganisms and showed excellent antibacterial activity.

The FiberTAG project: Tagging dietary fibre intake by measuring biomarkers related to the gut microbiota and their interest for health

The scientific rationale for dietary fibre intake recommendations comes from the recognition of their benefits for health based on studies first published many years ago. It remains unclear which are the key physiological effects generated by dietary fibre in view of the diversity of the food components considered as dietary fibre, of the relevance of their classification (soluble and insoluble) and from the recent discoveries putting forward their interactions with the gut microbiota. The project FiberTAG (Joint Programming Initiative 'A Healthy Diet for a Healthy Life' 2017-2020 https://www.fibertag.eu/) aims to establish a set of biomarkers (markers of gut barrier function and bacterial co-metabolites including volatile compounds and lipid derivatives), measured in different biological compartments (faeces, blood or breath) linking dietary fibre intake and gut microbiota-related health effects. The FiberTAG consortium brings together academic and industrial partners from Belgium, France, Germany and Canada to share data and samples obtained from existing as well as new intervention studies in order to evaluate the relevance of such biomarkers. The FiberTAG consortium is currently working on five existing cohorts (prospective observational or nutritional interventions in healthy or obese patients), and a number of new intervention studies to analyse the effect of insoluble dietary fibre (wheat bran and chitin-glucan, provided by the industrial partners) in healthy individuals or in obese patients at high cardiometabolic risk.

Chitin-glucan and pomegranate polyphenols improve endothelial dysfunction

The vascular dysfunction is the primary event in the occurrence of cardio-vascular risk, and no treatment exists until now. We tested for the first time the hypothesis that chitin-glucan (CG) - an insoluble fibre with prebiotic properties- and polyphenol-rich pomegranate peel extract (PPE) can improve endothelial and inflammatory disorders in a mouse model of cardiovascular disease (CVD), namely by modulating the gut microbiota. Male Apolipoprotein E knock-out (ApoE-/-) mice fed a high fat (HF) diet developed a significant endothelial dysfunction attested by atherosclerotic plaques and increasing abundance of caveolin-1 in aorta. The supplementation with CG + PPE in the HF diet reduced inflammatory markers both in the liver and in the visceral adipose tissue together with a reduction of hepatic triglycerides. In addition, it increased the activating form of endothelial NO-synthase in mesenteric arteries and the heme-nitrosylated haemoglobin (Hb-NO) blood levels as compared with HF fed ApoE-/- mice, suggesting a higher capacity of mesenteric arteries to produce nitric oxide (NO). This study allows to pinpoint gut bacteria, namely Lactobacillus and Alistipes, that could be implicated in the management of endothelial and inflammatory dysfunctions associated with CVD, and to unravel the role of nutrition in the modulation of those bacteria.