Structural Characterization and In Vitro Fermentation Characteristics of Enzymatically Extracted Black Mulberry Polysaccharides

In vitro simulated digestion and fermentation characteristics of pectic polysaccharides from fresh passion fruit (Passiflora edulis f. flavicarpa L.) peel

In this study, two pectic polysaccharides (PFP-T and PFP-UM) were extracted from fresh passion fruit peels using three-phase partitioning (TPP) and sequential ultrasound-microwave-assisted TPP methods, respectively, and their effects on the in vitro gastrointestinal digestion and fecal fermentation characteristics were examined. The results indicate that gastrointestinal digestion has a minimal effect on the physicochemical and structural characteristics of PFP-T and PFP-UM. However, during in vitro fecal fermentation, both undigested PFP-T and PFP-UM are significantly degraded and utilized by intestinal microorganisms, showing increased the total relative abundance of Firmicutes and Bacteroidota in the intestinal flora. Notably, compared with PFP-UM, PFP-T better promoted the reproduction of beneficial bacteria such as Prevotella, Megasphaera and Dialister, while suppressed the growth of harmful genera including Escherichia-Shigella, producing higher content of short-chain fatty acids. Therefore, our findings suggest that PFP-T derived from passion fruit peel has potential as a dietary supplement for promoting intestinal health.

In vitro human gut microbiota fermentation of litchi pulp polysaccharides as affected by Lactobacillus pre-treatment

In this study, litchi polysaccharides were obtained from unfermented or fermented pulp by Lactobacillus fermentum (denoted as LP and LPF, respectively). The differences between LP and LPF in the colonic fermentation characteristics and modulatory of gut microbiota growth and metabolism were investigated with an in vitro fecal fermentation model. Results revealed that the strategies of gut bacteria metabolizing LP and LPF were different and LPF with lower molecular weight (Mw) was readily utilized by bacteria. The monosaccharide utilization sequence of each polysaccharide was Ara > Gla > GalA > GlcA ≈ Glu ≈ Man. Moreover, LPF promoted stronger proliferation of Bifidobacterium, Megamonas, Prevotella, and Bacteroides and higher SCFAs production (especially acetic and butyric acids) than LP. Correlation analysis further revealed that Mw could represent an essential structural feature of polysaccharides associated with its microbiota-regulating effect. Overall, Lactobacillus fermentation pre-treatment of litchi pulp promoted the fermentation characteristics and prebiotic activities of its polysaccharide.

Exploration of green preparation strategy for Lycium barbarum polysaccharide targeting Bacteroides proliferative and immune-enhancing activities and its potential use in geriatric foods

Lycium barbarum polysaccharide (LBP) is beneficial for elderly people, but its use is limited in geriatric foods due to the lack of comprehensive information on its preparation strategy and physical property. In this study, the low-ester rhamnogalacturonan-I (RG-I) type pectic polysaccharide-protein complexes with varying physicochemical properties, structural characteristics, proliferative activities on Bacteroides, and immune-enhancing activities on RAW 264.7 cells, were obtained by moderate-temperature acid extraction within adjustment of enzymatic and physical pretreatments. LBP prepared by moderate-temperature acid extraction, namely S1-A, showed the strongest immune-enhancing activity via increasing the phagocytosis capacity and NO release of RAW 264.7 cells by 23 % and 76 %, respectively. S1-A exhibited relatively high viscosity and calcium ion response characteristic with the application potential for thickened liquid foods for the elderly with dysphagia. LBP prepared by composite cellulase and pectinase pretreatment combined with moderate-temperature acid extraction, namely S1-M1, showed the strongest Bacteroides proliferative activity that was equivalent to 0.60-0.97 times of that of inulin. S1-M1 exhibited extremely low viscosity and strong tolerance to food nutrients with high processing applicability for fluid foods. This study provided crucial data for the preparation and application of LBP targeting gut microbiota disorders and immunosenescence for the development of geriatric foods.

Extraction, purification, structural modification, activities and application of polysaccharides from different parts of mulberry

The mulberry plant is a member of the Moraceae family and belongs to the Morus genus. Its entire body is a treasure, with mulberries, mulberry leaves, and mulberry branches all suitable for medicinal use. The main active ingredient in mulberries is mulberry polysaccharide. Studies have shown that polysaccharides from different parts of mulberry exhibit antioxidant, antidiabetic, antibacterial, anti-inflammatory, and blood pressure-lowering properties. There are more studies on the biological activities, extraction methods, and structural characterization of polysaccharides from different parts of mulberry. However, the structural characterization of mulberry polysaccharides is mostly confined to the types and proportions of monosaccharides and the molecular weights of polysaccharides, and there are fewer systematic studies on polysaccharides from different parts of mulberry. In order to better understand the bioactive structure of mulberry polysaccharides, this article discusses the recent research progress in the extraction, separation, purification, bioactivity, structural modification, and application of polysaccharides from different parts of mulberry (mulberry leaves, mulberry fruits, and mulberry branches). It also delves into the pharmacological mechanisms of action of mulberry polysaccharides to provide a theoretical basis for further research on mulberry polysaccharides with a view to their deeper application in the fields of feed and nutraceuticals.

Microencapsulation with fructooligosaccharides and whey protein enhances the antioxidant activity of anthocyanins and their ability to modulate gut microbiota in vitro

Anthocyanins are the primary functional pigments in the diet. However, anthocyanins exhibit instability during digestion, coupled with limited bioavailability. Microencapsulation offers anthocyanins a sheltered environment, enhancing their stability and bioactivity. Fructooligosaccharides (FOS) and whey protein (WP) commonly serve as wall materials in microencapsulation and represent a significant source of probiotic functionality. Our prior research successfully established a robust microencapsulation system for anthocyanins utilizing FOS and WP. This study investigates the antioxidative capacity, stability during in vitro digestion, modulation on gut microbiota, and short-chain fatty acids (SCFAs) production of black soybean skin anthocyanins microencapsulated with FOS and WP (anthocyanin-loaded microencapsule particles, ALM). The results demonstrate that ALM exhibits a superior antioxidant capacity compared to free anthocyanins (ANCs) and cyanidin-3-glucoside (C3G). During simulated digestion, ALM exhibits enhanced anthocyanin retention compared with ANC in both gastric and intestinal phases. In comparison with ANC and even non-loaded microcapsules (NLM), in vitro fermentation demonstrates that ALM exhibits the highest gas production and lowered pH, indicating excellent fermentation activity. Furthermore, in comparison with ANC or NLM, ALM exerts a positive influence on the diversity and composition of gut microbiota, with potentially beneficial genera such as Faecalibacterium and Akkermansia exhibiting higher relative abundance. Moreover, ALM stimulates the production of SCFAs, particularly acetic and propionic acids. In conclusion, microencapsulation of anthocyanins with FOS-WP enhances their antioxidative capacity and stability during in vitro digestion. Simultaneously, this microencapsulation illustrates a positive regulatory effect on the intestinal microbiota community and SCFA production, conferring potential health benefits.

The promising stability of carboxylpyranocyanidin-3-O-glucoside during food processing and simulated digestion and its bioavailability research

BACKGROUND

Pyranoanthocyanins are stable anthocyanin derivatives. Carboxylpyranoanthocyanin is one of the simplest pyranoanthocyanin, among which the production of carboxylpyranocyanidin-3-O-glucoside (crboxyl-pycy-3-gluc) is most feasible as a result of the abundance of its reactant, cyanidin-3-O-glucoside (Cy-3-gluc).

RESULTS

In the present study, carboxyl-pycy-3-gluc was synthesized and its stability during processing and after ingestion as well as its bioavailability in vivo were comprehensively evaluated. Our results indicated that the color of carboxyl-pycy-3-gluc remained more stable compared to Cy-3-gluc when facing the large-span pH variation. The high retention of anthocyanin symbolized the superb stability under thermal processing, sulfur dioxide bleaching and ultrasonic treatment of carboxyl-pycy-3-gluc. Because of the stability under the alkaline condition, carboxyl-pycy-3-gluc is more stable after oral-gastrointestinal digestion. After in vitro gut microbiota fermentation, the retention of carboxyl-pycy-3-gluc was significantly higher than that of Cy-3-gluc. The larger molecular size made absorption of carboxyl-pycy-3-gluc into blood more difficult than its precursor.

CONCLUSION

The present study demonstrated the promising stability of carboxyl-pycy-3-gluc during food processing and after digestion, confirming the potential of carboxyl-pycy-3-gluc as a colorant. © 2023 Society of Chemical Industry.

Modulation of gut microbiota by crude mulberry polysaccharide attenuates knee osteoarthritis progression in rats

Mulberry (Morus alba L.), a kind of common fruits widely cultivated worldwide, has been proven various biological activities. However, its potential role in the progression of knee osteoarthritis (KOA) remains unclear. This study aims to investigate the potential protective effects of crude polysaccharide extracted from mulberry fruit, referred to as a complex blend of polysaccharides and other unidentified extracted impurities, on KOA progression. The KOA rats were established by injection of 1 mg sodium monoiodoacetate into knee, and administrated with crude mulberry polysaccharide (Mup) by gastric gavage for 4 weeks. Furthermore, intestinal bacteria clearance assay (IBCA) and fecal microbiota transplantation were conducted for the evaluation of the effect of gut microbiota (GM) on KOA. Our findings demonstrated that Mup, particularly at a dosage of 200 mg/kg, effectively improved abnormal gait patterns, reduced the level of inflammation, mitigated subchondral bone loss, restored compromised joint surfaces, alleviated cartilage destruction, and positively modulated the dysregulated profile of GM in KOA rats. Moreover, IBCA compromised the protective effects of Mup, while transplantation of fecal bacteria from Mup-treated rats facilitated KOA recovery. Collectively, our study suggested that Mup had the potential to ameliorate the progression of KOA, potentially through its modulation of GM profile.

Ripening induced degradation of pectin and cellulose affects the medium-and short-wave infrared drying characteristics of mulberry

Mulberries were categorized into five stages of ripening (D1-D5, 0.905-1.055 g/cm3) based on their density, and their physicochemical properties, tissue structure, cell wall polysaccharide properties, and drying characteristics were investigated. As mulberry ripening progressed, the TSS and water-soluble pectin content rapidly increased, while the contents of TA, hardness, chelate-, sodium carbonate-soluble pectin, hemicellulose, and cellulose decreased gradually. Pectin nanostructure and monosaccharide composition indicated that both the main and side chains of pectin undergo depolymerization. Medium- and short-wave infrared drying time initially decreased and then increased during mulberry ripening, with D4 fruits exhibiting the shortest drying time. Compared with D4 fruits, the collapse of cell structure in D5 fruits prolongs their drying time. The results demonstrate that ripeness significantly affects mulberry drying characteristics, which is related to changes in cell structure and pectin properties. Utilizing mulberry density to determine ripeness and grading is an effective approach to achieving optimal drying.

Characterization of Various Noncovalent Polyphenol-Starch Complexes and Their Prebiotic Activities during In Vitro Digestion and Fermentation

This study explores the structural characterization of six noncovalent polyphenol-starch complexes and their prebiotic activities during in vitro digestion and fermentation. Ferulic acid, caffeic acid, gallic acid, isoquercetin, astragalin, and hyperin were complexed with sweet potato starch (SPS). The polyphenols exhibited high binding capacity (>70%) with SPS. A partial release of flavonoids from the complexes was observed via in vitro digestion, while the phenolic acids remained tightly bound. Molecular dynamics (MD) simulation revealed that polyphenols altered the spatial configuration of polysaccharides and intramolecular hydrogen bonds formed. Additionally, polyphenol-SPS complexes exerted inhibitory effects on starch digestion compared to gelatinized SPS, owing to the increase in resistant starch fraction. It revealed that the different complexes stimulated the growth of Lactobacillus rhamnosus and Bifidobacterium bifidum, while inhibiting the growth of Escherichia coli. Moreover, in vitro fermentation experiments revealed that complexes were utilized by the gut microbiota, resulting in the production of short-chain fatty acids and a decrease in pH. In addition, the polyphenol-SPS complexes altered the composition of gut microbiota by promoting the growth of beneficial bacteria and decreasing pathogenic bacteria. Polyphenol-SPS complexes exhibit great potential for use as a prebiotic and exert dual beneficial effects on gut microbiota.

Effects of in vitro fecal fermentation on the metabolism and antioxidant properties of cyanidin-3-O-glucoside

Anthocyanins' potential health benefits have garnered significant interest. However, due to low bioavailability, the gut microbiota-associated metabolites are suspected to mediate their bioactivity. In this study, cyanidin-3-glucoside (C3G) was fermented with fecal inoculum to simulate colonic microbiota interaction in vitro. The metabolites and antioxidant properties of pre- (P-C3G) and post-fermentation (F-C3G) were determined. Fermentation significantly increased contents of five metabolites (cyanidin, protocatechuic acid, phloroglucinaldehyde, 4-hydroxybenzoic acid and 4-hydroxyphenylacetic acid). Additionally, F-C3G demonstrated superior radicals scavenging than P-C3G, as well as to alleviate H2O2-induced damage in HepG2 cell via increasing superoxide dismutase by 43.26% and catalase by 39.83%, reducing malonaldehyde by 16.40% and cellular ROS production, and activating Nrf2 pathway. Moreover, F-C3G significantly extended the survival rate by 20.67% of Caenorhabditis elegans under heat stress by antioxidation in vivo. This study suggested that anthocyanins metabolism by gut microbiota produce specific metabolites, which potentially exerts protection.

Fecal fermentation behavior and immunomodulatory activity of arabinoxylan from wheat bran

Arabinoxylan (AX) is the predominant non-starch polysaccharide in wheat bran, known for its significant immunomodulatory activity. However, existing literature lacks comprehensive studies on AX fermentation by gut microbiota and its subsequent immunomodulatory mechanisms. In the present study, we aimed to investigate the effects of AX on the composition of gut microbiota and the characteristics of its immunomodulatory activity. For this purpose, an in vitro fermentation system and a cyclophosphamide-induced immunosuppressed mouse model were established to explore both the in vitro and in vivo effects of AX on gut microbiota and immune modulation. The results demonstrated that AX was metabolized by gut microbes and in turn to promoting the production of short-chain fatty acids (SCFAs), which concurrently led to a significant decrease in pH. Furthermore, AX treatment significantly changed the microbial composition, elevated the relative abundance of Actinobacteria while reducing that of Bacteroidetes. In the immunosuppressed mice, AX administration improved the thymus and spleen indices, mitigated spleen injury, and bolstered overall immunity. Moreover, AX altered the gut microbiota structure, increasing the abundance of Bacteroidetes and decreasing that of Firmicutes. These findings suggest that wheat bran-derived AX can modulate intestinal microbial composition, improve gut microecology, and enhance host immunity by targeting gut microbiota.

The Prebiotic Activity of a Novel Polysaccharide Extracted from Huangshui by Fecal Fermentation In Vitro

A novel polysaccharide, HSP80-2, with an average molecular weight of 13.8 kDa, was successfully isolated by the gradient ethanol precipitation (GEP) method from Huangshui (HS), the by-product of Chinese Baijiu. It was mainly composed of arabinose, xylose, and glucose with a molar ratio of 4.0:3.1:2.4, which was completely different from the previous reported HS polysaccharides (HSPs). Morphological observations indicated that HSP80-2 exhibited a smooth but uneven fragmented structure. Moreover, HSP80-2 exerted prebiotic activity evaluated by in vitro fermentation. Specifically, HSP80-2 was utilized by gut microbiota, and significantly regulated the composition and abundance of beneficial microbiota such as Phascolarctobacterium, Parabacteroides, and Bacteroides. Notably, KEGG pathway enrichment analysis illustrated that HSP80-2 enriched the pathways of amino sugar and nucleotide sugar metabolism (Ko00520), galactose metabolism (ko00052), and the citrate cycle (TCA cycle) (ko00020). Meanwhile, the contents of short-chain fatty acids (SCFAs) mainly including acetic acid, propionic acid, and butyric acid in the HSP80-2 group were remarkably increased, which was closely associated with the growth of Lachnoclostridium and Parabacteroides. These results showed that HSP80-2 might be used as a potential functional factor to promote human gut health, which further extended the high value utilization of HS.

Effects of ultrasonic-enzymatic-assisted ethanol precipitation method on the physicochemical characteristics, antioxidant and hypoglycemic activities of Tremella fuciformis polysaccharides

This investigation involved the extraction of a novel polysaccharide from the spore fermentation broth of Tremella fuciformis using a method that combined ultrasonic and enzymatic assistance with ethanol precipitation. It was then compared with enzymatic and ultrasonic extraction methods. The objective of this research is to offer a reference point for expanding the application of ultrasonic-assisted enzymatic extraction technology in T. fuciformis polysaccharides (TFPs). Based on single-factor experiments, Box-Behnken was used to optimize the extraction conditions of TFPs by ultrasonic-enzymatic-assisted ethanol precipitation extraction. The results revealed an optimal combination of enzymes, with a cellulase-to-papain ratio of 2:1, an enzyme addition of 4000U/100 mL, an enzymolysis temperature of 49 °C, ultrasonicpower at 3 W/mL and an ultrasonictime of 20 min. The extraction rate of TFPs and α- amylase inhibition rates were 23.94 % and 61.44 %, respectively. Comparing the physicochemical properties, structural characterization and in vitro activity of TFPs extracted through different methods, the results showed that ultrasonic treatment significantly influences the apparent morphology of polysaccharide and could enhance its in vitro biological activity. However, different extraction techniques exhibit insubstantial impact on the chemical composition, glycosidic bonds or glycosidic ring configurations within the polysaccharides. Among them, ultrasonic-enzymatic-assisted ethanol precipitation extraction of polysaccharide has the highest extraction rate and the lowest viscosity. It has significant effects on ABTS+ scavenging activity, α- amylase inhibition rate and glucose dialysis retardation index, polysaccharide treated with ultrasonic-enzymatic showed the best performance. These findings suggest that ultrasonic-enzymatic-assisted ethanol precipitation extraction can enhance the activities of TFPs, thereby providing a valuable insight for their future development and application.

Fermentation patterns of prebiotics fructooligosaccharides-SCFA esters inoculated with fecal microbiota from ulcerative colitis patients

Ulcerative colitis (UC) is believed to arise from an imbalance between the intestinal microbiota and mucosal immunity, leading to excessive intestinal inflammation. Modulating the gut microbial community through dietary components presents a valuable strategy in aiding the treatment of UC. In this study, esters formed by binding of well-known prebiotics, fructooligosaccharides (FOS), with short chain fatty acids (SCFAs) via both enzymatic and chemical methods were evaluated for their impact on the gut microbiota of UC patients. An in vitro human colonic fermentation model was employed to monitor changes in total carbohydrates and SCFAs production during the fermentation of these esters by microbiota from patients with active and remission UC. The results showed that pronounced abundance of [Ruminococcus]_gnavus_group, Escherichia_Shigella, Lachnoclostridium, Klebsiella and other potential pathogens were detected in the fecal samples from UC patients, with a milder condition observed during the remission phase. Significant higher levels of corresponding SCFA were observed in the groups with addition of FOS-SCFAs esters during fermentation. Butyrylated fructooligosaccharides (B-FOS) and propionylated fructooligosaccharides (P-FOS) by enzymatic synthesis successfully promoted the proliferation of Bifidobacterium and inhibited Clostridium_sensu_stricto_1 and Klebsiella. Overall, B-FOS and P-FOS exhibit promising potential for restoring intestinal homeostasis and alleviating intestinal inflammation in individuals with UC.

Insights into the fermentation patterns of wheat bran cell wall polysaccharides using an in-vitro batch fermentation model

We aimed to study the structural characteristics and fermentation properties of wheat bran cell wall polysaccharides (CWPs). Sequential extractions of CWPs from wheat bran produced the water-extractable (WE) and alkali-extractable (AE) fractions. The extracted fractions were structurally characterized based on their molecular weight (Mw) and monosaccharide composition. Our findings revealed that the Mw and the ratio of arabinose to xylose (A/X) of AE were higher than those of WE and that the two fractions were mainly composed of arabinoxylans (AXs). The substrates were then subjected to in vitro fermentation by human fecal microbiota. As fermentation progressed, the total carbohydrates of WE were significantly more utilized than that of AE (p < 0.05). The AXs in WE were utilized at a higher rate than those in AE. The relative abundance of Prevotella_9, which can efficiently utilize AXs, was significantly increased in AE. The presence of AXs in AE shifted the balance away from protein fermentation and caused a delay in protein fermentation. Our study demonstrated that wheat bran CWPs can modulate the gut microbiota in a structure-dependent manner. However, future studies should further characterize the fine structure of wheat CWPs to clarify their detailed relationship with gut microbiota and metabolites.

Effects and Mechanistic Role of Mulberry Leaves in Treating Diabetes and its Complications

Diabetes mellitus (DM) has become a surge burden worldwide owing to its high prevalence and range of associated complications such as coronary artery disease, blindness, stroke, and renal failure. Accordingly, the treatment and management of DM have become a research hotspot. Mulberry leaves (Morus alba L.) have been used in Traditional Chinese Medicine for a long time, with the first record of its use published in Shennong Bencao Jing (Shennong's Classic of Materia Medica). Mulberry leaves (MLs) are considered highly valuable medicinal food homologs that contain polysaccharides, flavonoids, alkaloids, and other bioactive substances. Modern pharmacological studies have shown that MLs have multiple bioactive effects, including hypolipidemic, hypoglycemic, antioxidation, and anti-inflammatory properties, with the ability to protect islet [Formula: see text]-cells, alleviate insulin resistance, and regulate intestinal flora. However, the pharmacological mechanisms of MLs in DM have not been fully elucidated. In this review, we summarize the botanical characterization, traditional use, chemical constituents, pharmacokinetics, and toxicology of MLs, and highlight the mechanisms involved in treating DM and its complications. This review can provide a valuable reference for the further development and utilization of MLs in the prevention and treatment of DM.

Structural characteristics and in vitro fermentation patterns of polysaccharides from Boletus mushrooms

The aim of this study was to investigate the structural characteristics and in vitro fermentation patterns of polysaccharides from Boletus mushrooms. Polysaccharides were solubilized from fruit bodies of selected mushrooms Boletus auripes, B. bicolor, and B. griseus using subcritical water extraction. Boletus polysaccharides were characterized for their general physicochemical pattern, constituent monosaccharides and molecular weight. A simulated in vitro fermentation model was used to study the utilization of Boletus polysaccharides by the gut microbiota and their consequent modulation of microbial communities. Results showed that the main constituent monosaccharides of Boletus polysaccharides were glucose, galactose and mannose, followed by fucose, xylose and rhamnose, with glucose being the most abundant. The polysaccharides from B. bicolor and B. griseus exhibited a relatively high proportion of galactose and mannose, respectively. Boletus polysaccharides exhibited a wide range of molecular weights (5 kDa to 2000 kDa), which covered multiple polysaccharide populations, but the proportions of these populations varied among the samples. Boletus polysaccharides were gradually utilized by the human fecal microbiota, promoting the production of SCFAs. Boletus polysaccharides contributed to a healthier gut microbiota composition by increasing the relative abundance of beneficial bacterial genera such as Bacteroides and Faecalibacterium and reducing the relative abundance of harmful bacterial genera such as Sutterella and Escherichia-Shigella. B. bicolor polysaccharides showed better fermentability and prebiotic effects than the other Boletus polysaccharide groups. Therefore, the consumption of select Boletus mushrooms, particularly B. bicolor, could be a potential approach to obtain polysaccharides for microbiota modulation and to support gut health.

Structure Characterization and Immunomodulatory Activity of Misgurnus anguillicaudatus Carbohydrates

Misgurnus anguillicaudatus, also known as oriental weather loach, is widely consumed and favored in East Asia due to its superior nutritional values and excellent flavor. In this study, a crude Misgurnus anguillicaudatus carbohydrates (MAC) was isolated from Misgurnus anguillicaudatus. Subsequently, two parts, which were named MAO and MAP, respectively, were separated from MAC, and their primary structures and immunomodulatory activity were investigated. The results showed that MAO had a molecular weight of 2854 Da, and principally consisted of arabinose (77.11%) and rhamnose (21.97%), together with minor levels of fucose (0.92%); MAP, with a molecular weight of 3873 Da, was mainly composed of fucose (87.55%) and a small amount of rhamnose (8.86%) and galactose (3.59%). The in vitro assay showed that MAC could significantly enhance the proliferation of macrophages without cytotoxicity and increase the production of immune substances (TNF-α, IL-6). Together with Western blot results, we speculated that MAC could stimulate RAW264.7 murine macrophage cells to secrete TNF-α and IL-6 through up-regulating TLR4-MAPK-p38 signaling pathways. The results indicated that MAC could be a potential immune agent and might provide meaningful information for further chain conformation and immune mechanism research.

Comparative Study on In Vitro Fermentation Characteristics of the Polysaccharides Extracted from Bergamot and Fermented Bergamot

This study aimed to compare the in vitro fermentation characteristics of polysaccharides from Bergamot and Laoxianghuang (fermented 1, 3, and 5 years from bergamot) using the stable in vitro human gut fermentation model. Results showed that bergamot polysaccharide (BP) and Laoxianghuang polysaccharides (LPs) with different surface topographies were characterized as mannorhamnan (comprising Mannose and Rhamnose) and polygalacturonic acid (comprising Galacturonic acid and Galactose), respectively. The distinct effects on the gut microbiota and metabolome of BP and LPs may be due to their different monosaccharide compositions and surface morphologies. BP decreased harmful Fusobacterium and promoted beneficial Bifidobacterium, which was positively correlated with health-enhancing metabolites such as acetic acid, propionic acid, and pyridoxamine. Lactobacillus, increased by LPs, was positively correlated with 4-Hydroxybenzaldehyde, acetic acid, and butyric acid. Overall, this study elucidated gut microbiota and the metabolome regulatory discrepancies of BP and LPs, potentially contributing to their development as prebiotics in healthy foods.

Structural, in vitro digestion, and fermentation characteristics of lotus leaf flavonoids

Bioaccessibility and bioactivity of flavonoids in lotus leaves are related to their characteristics in gastrointestinal digestion and colonic fermentation. The aim of this study is to investigate the stability of lotus leaf flavonoids (LLF) in simulated gastrointestinal digestion, and its modulation on gut microbiota in vitro fermentation. Results showed that LLF mainly consisted of quercetin-3-O-galactoside, quercetin-3-O-glucuronide, quercetin-3-O-glucoside, and kaempferol-3-O-glucoside. These flavonoids kept stability with only a small fraction degraded in simulated gastric and intestinal fluids. In vitro fermentation, LLF stimulated the growth of Actinobacteria and Firmicutes, inhibited the growth of Proteobacteria, and induced the production of fermentation gases and short-chain fatty acids. Interestingly, supplementation of soluble starch significantly improved the utilization of LLF by the intestinal flora. These results revealed that LLF shaped a unique biological web with Lactobacillus and Bifidobacterium spp. as the core of the biological network, which would be more beneficial to gut health.

High-performance carboxymethyl cellulose-based hydrogel film for food packaging and preservation system

Most traditional food packaging and preservation films suffer from limited stretchability and relatively simple functionality, which severely restricts their practical application. In this study, a highly stretchable and versatile sodium carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA)/poly(ethylene imine) (PEI)/tannic acid (TA) hydrogel film was elaborately designed and demonstrated as an efficient food packaging and preservation system. The dynamic reversible non-covalent within three-dimensional (3D) network structures served as sacrificial bonds to dissipate the loaded energy and endowed the hydrogel film with excellent elongation ~400 %, which is much larger than that of conventional food packaging films (<50 %). Furthermore, the optimized CMC/PVA/PEI/TA₃ hydrogel film delivers versatile performances, including self-healing, whole UV-blocking (<400 nm), strong adhesive strength (234.08 KPa), antioxidation virtues, oxygen barrier (32.64 cm³*μm/(m²*d*KPa)) and water vapor barrier (642.92 g/(m²*24 h)). Notably, the shelf life of fresh strawberries, mangoes, and cherries was prolonged by at least one week under ambient conditions when the packaging box was covered by the fabricated CMC/PVA/PEI/TA₃ film. Thus, our work not only provides a highly stretchable and versatile hydrogel film but also boosts the in-depth comprehension and rational design of robust food packaging and preservation films.

Effect of Ultrasonic Irradiation on the Physicochemical and Structural Properties of Laminaria japonica Polysaccharides and Their Performance in Biological Activities

Due to the large molecular weight and complex structure of Laminaria japonica polysaccharides (LJP), which limit their absorption and utilization by the body, methods to effectively degrade polysaccharides had received more and more attention. In the present research, hot water extraction coupled with three-phase partitioning (TPP) was developed to extract and isolate LJP. Ultrasonic L. japonica polysaccharides (ULJP) were obtained by ultrasonic degradation. In addition, their physicochemical characteristics and in vitro biological activities were investigated. Results indicated that ULJP had lower weight-average molecular weight (153 kDa) and looser surface morphology than the LJP. The primary structures of LJP and ULJP were basically unchanged, both contained α-hexo-pyranoses and were mainly connected by 1,4-glycosidic bonds. Compared with LJP, ULJP had stronger antioxidant activity, α-amylase inhibitory effect and anti-inflammatory effect on RAW264.7 macrophages. The scavenging rate of DPPH free radicals by ULJP is 35.85%. Therefore, ultrasonic degradation could effectively degrade LJP and significantly improve the biological activity of LJP, which provided a theoretical basis for the in-depth utilization and research and development of L. japonica in the fields of medicine and food.

Extraction, purification, structural characterization, and gut microbiota relationship of polysaccharides: A review

Intestinal dysbiosis is one of the major causes of the occurrence of metabolic syndromes, such as obesity, diabetes, nonalcoholic fatty liver disease, and cardiovascular diseases. Polysaccharide-based microbial therapeutic strategies have excellent potential in the treatment of metabolic syndromes, but the underlying regulatory mechanisms remain elusive. Identification of the internal regulatory mechanism of the gut microbiome and the interaction mechanisms involving bacteria and the host are essential to achieve precise control of the gut microbiome and obtain valuable clinical data. Polysaccharides cannot be directly digested; the behavior in the intestinal tract is considered a "bridge" between microbiota and host communication. To provide a relatively comprehensive reference for researchers in the field, we will discuss the polysaccharide extraction and purification processes and chemical and structural characteristics, focusing on the polysaccharides in gut microbiota through the immune system, gut-liver axis, gut-brain axis, energy axis interactions, and potential applications.