The derivatization and antioxidant activities of yeast mannan

Ultrasonic-assisted extraction, analysis and properties of purple mangosteen scarfskin polysaccharide and its acetylated derivative

Purple mangosteen scarfskin polysaccharide has many important physiological functions, but its preparation method, structure, and function need further exploration. A polysaccharide was obtained from mangosteen scarfskin by ultrasonic-assisted extraction and purified. On this basis, its structure and physicochemical properties were investigated. The Congo red experiment was used to determine whether it has a triple helix conformation. The structure of purple mangosteen scarfskin polysaccharide was further analyzed by infrared spectroscopy and nuclear magnetic analysis. The antioxidant activities of the above three polysaccharides were studied by related experiments. It was found that the monosaccharide composition of purple mangosteen scarfskin polysaccharide mainly contained a large amount of arabinose, a small amount of rhamnoose and a very small amount of galacturonic acid, and its core main chain was composed of 1,4-α-arabinose. It did not have this spatial configuration. After the acetylation of purple mangosteen scarfskin polysaccharide, the acetylated derivative with a degree of substitution of 0.33 was obtained. It was found that they had certain scavenging and inhibiting effects on hydroxyl radicals and lipid peroxidation, and their activities were related to the concentration of polysaccharides. Meanwhile, the antioxidant activity of the polysaccharide was significantly enhanced after the modified treatment of acetylation, which indicated that chemical modification could effectively improve some activities of polysaccharide. The above studies provided some reference value for the further research and development of purple mangosteen scarfskin polysaccharide.

The ultrasonic-assisted enzymatic extraction, characteristics and antioxidant activities of lychee nuclear polysaccharide

A response surface methodology (RSM) and one-factor method were established to investigate the optimum conditions for the extraction of lychee nuclear polysaccharides (LSP) by ultrasonic-assisted pectinase. The content of basic components in polysaccharides was determined. The antioxidant activity was well determined and compared the differences in the activities of the polysaccharides extracted by water extraction (LSP-HW) and those extracted at ultrasound-assisted enzyme (LSP-UAE). The activity of lychee nuclear polysaccharide increased with the increase of concentration. The anti-hydroxyl radical and anti-lipid peroxidation abilities of lychee nuclear polysaccharide were more excellent, and LSP-HW was slightly better than LSP-UAE in terms of activity, but the difference was not significant. In terms of solubility; LSP-HW without deproteinization was the best, followed by LSP-UAE, and the worst was LSP-UAE after deproteinization. The higher the glycoprotein content, the better the solubility of its polysaccharide. Compared with the existing extraction methods, this experiment greatly improved the extraction rate of lychee nuclear polysaccharides and further enriched the antioxidant activities of polysaccharides.

Antioxidant activity of polysaccharide from Garcinia mangostana rind and their derivatives

BACKGROUND

Polysaccharide from Garcinia mangostana rind has many biological activities and deserves further research.

METHODS

The antioxidant properties of UAEE-GMRP, UAEE-GMRP-1 A, CM-30, and Ac-30 were evaluated through two different antioxidant activity experimental systems.

RESULTS

The four polysaccharides had a better scavenging effect on hydroxyl radicals, while their inhibitory effect on lipid peroxidation was relatively weak. However, overall, the four polysaccharides showed a certain degree of potential application in the two antioxidant experiments mentioned above, especially the chemically modified polysaccharides from Garcinia mangostana rind, which effectively improved their antioxidant activity. This also indicates that chemical modification is a better method to improve polysaccharide activity. In addition, in these two antioxidant exploration experiments, carboxymethylated polysaccharide showed stronger activity compared to the other three polysaccharides.

CONCLUSION

The carboxymethylation modification may have great potential for application.

The effects of ultrasonic processing on the antioxidant activity of Geotrichum candidum LG-8 and its cell wall extracts

Introduction

Extraction techniques that influence cell wall polysaccharides (EPS) is crucial for maximizing their bioactivity. This study evaluates ultrasound technology for extracting antioxidant polysaccharides from Geotrichum candidum LG-8, assessing its impacton antioxidant activity.

Methods

Ultrasound extraction of EPS from G. candidum LG-8 was optimized (18 min, pH 7.0, 40 W/cm2, 0.75 M NaCl). ABTS scavenging efficiency and monosaccharide composition of LG-EPS1 and LG-EPS3 were analyzed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).

Results

The Results showed that ultrasonic treatment markedly increased the ABTS radical scavenging efficiency of LG-8 cells by 47%. At a concentration of 1 mg/mL, the ultrasonically extracted LG-EPS1 and LG-EPS3 polysaccharides exhibited significant ABTS radical scavenging efficiencies of 26% and 51%, respectively. Monosaccharide composition analysis identified mannose and glucose in LG-EPS1, while LG-EPS3 was primarily composed of mannose. FTIR spectra verified the polysaccharides' presence, and SEM provided visual confirmation of the nanoparticle structures characteristic of LG-EPS1 and LG-EPS3.

Discussion

This research not only underscores the technological merits of ultrasound in polysaccharide extraction but also highlights the potential of G. candidum LG-8 derived polysaccharides as valuable bioactive compounds for antioxidant utilization.

Potential Application of Yeast Cell Wall Biopolymers as Probiotic Encapsulants

Biopolymers of yeast cell walls, such as β-glucan, mannoprotein, and chitin, may serve as viable encapsulants for probiotics. Due to its thermal stability, β-glucan is a suitable cryoprotectant for probiotic microorganisms during freeze-drying. Mannoprotein has been shown to increase the adhesion of probiotic microorganisms to intestinal epithelial cells. Typically, chitin is utilized in the form of its derivatives, particularly chitosan, which is derived via deacetylation. Brewery waste has shown potential as a source of β-glucan that can be optimally extracted through thermolysis and sonication to yield up to 14% β-glucan, which can then be processed with protease and spray drying to achieve utmost purity. While laminarinase and sodium deodecyle sulfate were used to isolate and extract mannoproteins and glucanase was used to purify them, hexadecyltrimethylammonium bromide precipitation was used to improve the amount of purified mannoproteins to 7.25 percent. The maximum chitin yield of 2.4% was attained by continuing the acid-alkali reaction procedure, which was then followed by dialysis and lyophilization. Separation and purification of yeast cell wall biopolymers via diethylaminoethyl (DEAE) anion exchange chromatography can be used to increase the purity of β-glucan, whose purity in turn can also be increased using concanavalin-A chromatography based on the glucan/mannan ratio. In the meantime, mannoproteins can be purified via affinity chromatography that can be combined with zymolase treatment. Then, dialysis can be continued to obtain chitin with high purity. β-glucans, mannoproteins, and chitosan-derived yeast cell walls have been shown to promote the survival of probiotic microorganisms in the digestive tract. In addition, the prebiotic activity of β-glucans and mannoproteins can combine with microorganisms to form synbiotics.

The antioxidant activity of polysaccharides: A structure-function relationship overview

Over the last years, polysaccharides have been linked to antioxidant effects using both in vitro chemical and biological models. The reported structures, claimed to act as antioxidants, comprise chitosan, pectic polysaccharides, glucans, mannoproteins, alginates, fucoidans, and many others of all type of biological sources. The structural features linked to the antioxidant action include the polysaccharide charge, molecular weight, and the occurrence of non-carbohydrate substituents. The establishment of structure/function relationships can be, however, biased by secondary phenomena that tailor polysaccharides behavior in antioxidant systems. In this sense, this review confronts some basic concepts of polysaccharides chemistry with the current claim of carbohydrates as antioxidants. It critically discusses how the fine structure and properties of polysaccharides can define polysaccharides as antioxidants. Polysaccharides antioxidant action is highly dependent on their solubility, sugar ring structure, molecular weight, occurrence of positive or negatively charged groups, protein moieties and covalently linked phenolic compounds. However, the occurrence of phenolic compounds and protein as contaminants leads to misleading results in methodologies often used for screening and characterization purposes, as well as in vivo models. Despite falling in the concept of antioxidants, the role of polysaccharides must be well defined according with the matrices where they are involved.

Ultrasound-assisted enzyme extraction and properties of Shatian pomelo peel polysaccharide

In this study, Shatian pomelo peel was used as the raw material for extracting polysaccharides using hot water extraction (HW) and ultrasonic-assisted enzyme (UVE) methods, respectively. The optimal parameters for extractingShatian pomelo peel polysaccharides (StPP) using the ultrasound-assisted enzymatic method were determined using response surface methodology (RSM). The optimal conditions for the extraction of StPP were as follows: ultrasound power 350 W, ultrasound time 50 min, enzymatic digestion time 50 min, compound enzyme addition 1.5%, and enzymatic digestion temperature 55 °C. The yield of StPP was found to be 30.1310% under these conditions. Comparing the physicochemical properties and antioxidant activity of StPP extracted using different methods, it was observed that ultrasound-assisted enzyme extraction resulted in higher yield, sugar content and glucuronic acid content of StPP compared to traditional hot water extraction. Additionally, StPP extracted by ultrasound-assisted enzyme extraction showed better antioxidant activity. These results suggest that ultrasound-assisted enzymatic extraction is an effective method to enhance the activity of natural polysaccharides.

Effect of drying technology in Saccharomyces cerevisiae mannans: Structural, physicochemical, and functional properties

Mannans are polysaccharides whose physicochemical and biological properties render them commercialization in several products. Since these properties are strongly dependent on production conditions, the present study aims to assess the impact of different drying technologies - freeze (FDM) and spray drying (SDM) - on the structural, physicochemical, and biological properties of mannans from Saccharomyces cerevisiae. Structural analysis was assessed by FT-IR, PXRD and SEM, whereas physicochemical properties were evaluated based on sugars, protein, ash and water contents, solubility, and molecular weight distribution. Thermal behaviour was analysed by DSC, and antioxidant activity by DPPH and ABTS assays. The parameters which revealed major differences, in terms of structural and physicochemical properties regarded morphology (SEM), physical appearance (colour), moisture (3.6 ± 0.1 % and 11.9 ± 0.6 % for FDM and SDM, respectively) and solubility (1 mg/mL for FDM and 25 mg/mL for SDM). Nevertheless, these differences were not translated into the antioxidant capacity.

High Antioxidant Capacity of Lacticaseibacillus paracasei TDM-2 and Pediococcus pentosaceus TCM-3 from Qinghai Tibetan Plateau and Their Function towards Gut Modulation

Probiotic supplementation is a key therapeutic strategy for promoting gut health and maintaining gut homeostasis by modulating functional microbiota. In this study, we isolated two lactic acid bacteria (LAB) strains, Pediococcus pentosaceus TCM-3 and Lacticaseibacillus paracasei TDM-2, from Qinghai-Tibetan plateau, and evaluated their probiotic properties and antioxidant bioactivity. In which, TDM-2 had higher T-AOC activity than either TCM-3 or LGG (4.10 μmol/mL vs. 3.68 and 3.53 μmol/mL, respectively, p < 0.05). These strains have shown high antioxidant activity compared to the LAB strains and were found to be acid and bile salt tolerant, confronting the safety issues of antibiotic resistance and the capability of surviving in simulated gastric and intestinal juices. In vitro fermentation experiments with human gut microbiota revealed significant differences in microbial community composition between samples supplemented with TCM-3 and TDM-2 and those without. The addition of these two strains resulted in an enrichment of beneficial taxa, such as the Pediococcus, Lactobacillus, and Clostridium_sensu_strictos at the genus level, and Firmicutes and Proteobacteria at the phylum level. Notably, the TCM-3 group exhibited higher short-chain fatty acid production than the TDM-2 group and untreated controls (acetic acid at 12 h: 4.54 mmol L^-1 vs. 4.06 mmol L^-1 and 4.00 mmol L^-1; acetic acid at 24 h: 4.99 mmol L^-1 vs. 4.90 mmol L^-1 and 4.82 mmol L^-1, p < 0.05). These findings demonstrate that LAB supplementation with high antioxidant capacity and probiotic properties can promote gut health by modulating functional microbiota and is enriching for beneficial taxa. Our study provides guidance for therapeutic strategies that use novel LAB strains to maintain gut homeostasis and functional microbiota modulation.

Mannan oligosaccharides alleviate oxidative injury in the head kidney and spleen in grass carp (Ctenopharyngodon idella) via the Nrf2 signaling pathway after Aeromonas hydrophila infection

BACKGROUND

Mannan oligosaccharides (MOS) are recommended as aquaculture additives owing to their excellent antioxidant properties. In the present study, we examined the effects of dietary MOS on the head kidney and spleen of grass carp (Ctenopharyngodon idella) with Aeromonas hydrophila infection.

METHODS

A total of 540 grass carp were used for the study. They were administered six gradient dosages of the MOS diet (0, 200, 400, 600, 800, and 1,000 mg/kg) for 60 d. Subsequently, we performed a 14-day Aeromonas hydrophila challenge experiment. The antioxidant capacity of the head kidney and spleen were examined using spectrophotometry, DNA fragmentation, qRT-PCR, and Western blotting.

RESULTS

After infection with Aeromonas hydrophila, 400-600 mg/kg MOS supplementation decreased the levels of reactive oxygen species, protein carbonyl, and malonaldehyde and increased the levels of anti-superoxide anion, anti-hydroxyl radical, and glutathione in the head kidney and spleen of grass carp. The activities of copper-zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione S-transferase, glutathione reductase, and glutathione peroxidase were also enhanced by supplementation with 400-600 mg/kg MOS. Furthermore, the expression of most antioxidant enzymes and their corresponding genes increased significantly with supplementation of 200-800 mg/kg MOS. mRNA and protein levels of nuclear factor erythroid 2-related factor 2 also increased following supplementation with 400-600 mg/kg MOS. In addition, supplementation with 400-600 mg/kg MOS reduced excessive apoptosis by inhibiting the death receptor pathway and mitochondrial pathway processes.

CONCLUSIONS

Based on the quadratic regression analysis of the above biomarkers (reactive oxygen species, malondialdehyde, and protein carbonyl) of oxidative damage in the head kidney and spleen of on-growing grass carp, the recommended MOS supplementation is 575.21, 557.58, 531.86, 597.35, 570.16, and 553.80 mg/kg, respectively. Collectively, MOS supplementation could alleviate oxidative injury in the head kidney and spleen of grass carp infected with Aeromonas hydrophila.

Dietary 1,3-β-Glucans Affect Growth, Breast Muscle Composition, Antioxidant Activity, Inflammatory Response, and Economic Efficiency in Broiler Chickens

Recently, researchers have been intensively looking for novel, safe antibiotic alternatives because of the prevalence of many clinical and subclinical diseases affecting bird flocks and the risks of using antibiotics in subtherapeutic doses as feed additives. The present study intended to evaluate the potential use of 1,3-β-glucans (GLC) as antibiotic alternative growth promotors and assessed the effect of their dietary inclusion on the growth performance, carcass traits, chemical composition of breast muscles, economic efficiency, blood biochemical parameters, liver histopathology, antioxidant activity, and the proinflammatory response of broiler chickens. This study used 200 three-day-old ROSS broiler chickens (50 chicks/group, 10 chicks/replicate, with an average body weight of 98.71 ± 0.17 g/chick). They were assigned to four experimental groups with four dietary levels of GLC, namely 0, 50, 100, and 150 mg kg−1, for a 35-day feeding period. Birds fed diets containing GLC showed an identical different growth rate to the control group. However, the total feed intake (TFI) increased quadratically in the GLC50 and GLC100 groups as compared to that in the control group. GLC addition had no significant effect on the weights of internal and immune organs, except for a decrease in bursal weight in the GLC150 group (p = 0.01). Dietary GLC addition increased the feed cost and total cost at 50 and 100 mg kg−1 doses. The percentages of n-3 and n-6 PUFA in the breast muscle of broiler chickens fed GLC-supplemented diets increased linearly in a dose-dependent manner (p < 0.01). The serum alanine aminotransferase (ALT) level and the uric acid level were quadratically increased in the GLC150 group. The serum levels of total antioxidant capacity, catalase, superoxide dismutase, interleukin-1β, and interferon-gamma linearly increased, while the MDA level decreased in the GLC-fed groups in a dose-dependent manner. Normal histological characterization of different liver structures in the different groups with moderate round cells was noted as a natural immune response around the hepatic portal area. The different experimental groups showed an average percentage of positive immunostaining to the proinflammatory marker transforming growth factor-beta with an increase in the dose of GLC addition. The results suggest that GLC up to 100 mg kg−1 concentration can be used as a feed additive in the diets of broiler chickens and shows no adverse effects on their growth, dressing percentage, and internal organs. GLC addition in diets improves the antioxidant activity and immune response in birds. GLC help enrich the breast muscle with n-3 and n-6 polyunsaturated fatty acids.

A novel Stauntonia leucantha fruits arabinogalactan: and structural characterization

Polysaccharides were the key ingredients of many herbal medicines, and were responsible for multiple pharmacological activities. In this study, a novel polysaccharide fraction, named SLP-2, was isolated from Stauntonia leucantha fruits, and purified by DEAE-52 and Sephadex G-100 column chromatography. Furthermore, SLP-2 was identified by congo red, methylation, partial acid hydrolysis and NMR. The results indicated that the backbone of SLP-2 was composed of →4)-β-D-Galp-(1 → 4)-β-D-Galp-(1→ substituted at C-6 with 1,5-linked arabinan. SLP-2 had good anti-oxidation ability in vitro. Surprisingly, we found that reduction of carboxyl groups and methylation of hydroxyl groups enhanced the ability to scavenge 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and inhibit lipid peroxidation, and weakened the activity to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reduce ferric iron.

Yeast Extract: Characteristics, Production, Applications and Future Perspectives

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

Effects of Five Prebiotics on Growth, Antioxidant Capacity, Non-Specific Immunity, Stress Resistance, and Disease Resistance of Juvenile Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

To explore the short-term health benefits of five prebiotics on hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂), six experimental groups fed with different diets (basal diet, diet control (CON); basal diet + 0.2% fructooligosaccharide (FOS), diet FOS; basal diet + 0.5% chitosan, diet chitosan (CTS); basal diet + 0.2% mannan-oligosaccharide (MOS), diet MOS; basal diet + 0.1% β-glucan (GLU), Diet GLU; basal diet + 0.05% xylooligosaccharide (XOS), diet XOS) were set up, and a 4-week feeding trial was conducted. MOS and XOS significantly improved the growth of hybrid grouper compared to the CON group (p < 0.05). Antioxidant enzyme assay showed that the activity of glutathione peroxidase (GPx) was significantly enhanced in the MOS group, and the content of malondialdehyde (MDA) in the XOS group was significantly lower than in the CON group (p < 0.05). The catalase (CAT) activities were significantly enhanced in all prebiotic-supplemented groups compared with the CON group (p < 0.05). Non-specific immunity assay showed that the activities of alkaline phosphatase (AKP) and lysozyme (LZM) were significantly increased in all prebiotic-supplemented groups compared with the CON group (p < 0.05). The total protein content in the XOS group was significantly increased (p < 0.05), and the albumin (ALB) activity in the MOS group was more significantly increased than that in the CON group. Histological examination of the intestine revealed that muscle thickness was significantly increased in all prebiotic-supplemented groups compared to the CON group (p < 0.05). Villi length, villi width, muscle thickness all increased significantly in the MOS group (p < 0.05). In addition, the crowding stress and ammonia nitrogen stress experiments revealed that the survival rates of the MOS and XOS groups after stresses were significantly higher than those of the CON group (p < 0.05). Though MOS and XOS exhibited similar anti-stress effects, the antioxidant and non-specific immunity parameters they regulated were not the same, indicating that the specific mechanisms of MOS and XOS's anti-stress effects were probably different. After being challenged with Vibrio harvey, MOS and GLU groups showed significantly higher post-challenge survival rates than the CON group (p < 0.05). These findings indicated that among the five prebiotics, MOS and XOS showed the best overall short-term beneficial effects and could be considered promising short-term feed additives to improve the stress resistance of juvenile hybrid grouper.

Potential of Wood Hemicelluloses and Their Derivates as Food Ingredients

A holistic utilization of all lignocellulosic wood biomass, instead of the current approach of using only the cellulose fraction, is crucial for the efficient, ecological, and economical use of the forest resources. Use of wood constituents in the food and feed sector is a potential way of promoting the global economy. However, industrially established food products utilizing such components are still scarce, with the exception of cellulose derivatives. Hemicelluloses that include xylans and mannans are major constituents of wood. The wood hemicelluloses are structurally similar to hemicelluloses from crops, which are included in our diet, for example, as a part of dietary fibers. Hence, structurally similar wood hemicelluloses have the potential for similar uses. We review the current status and future potential of wood hemicelluloses as food ingredients. We include an inventory of the extraction routes of wood hemicelluloses, their physicochemical properties, and some of their gastrointestinal characteristics, and we also consider the regulatory route that research findings need to follow to be approved for food solutions, as well as the current status of the wood hemicellulose applications on that route.

Comparative Analysis of Mannans Extraction Processes from Spent Yeast Saccharomyces cerevisiae

Mannans are outstanding polysaccharides that have gained exponential interest over the years. These polysaccharides may be extracted from the cell wall of Saccharomyces cerevisiae, and recovered from the brewing or synthetic biology industries, among others. In this work, several extraction processes-physical, chemical and enzymatic-were studied, all aiming to obtain mannans from spent yeast S. cerevisiae. Their performance was evaluated in terms of yield, mannose content and cost. The resultant extracts were characterized in terms of their structure (FT-IR, PXRD and SEM), physicochemical properties (color, molecular weight distribution, sugars, protein, ash and water content) and thermal stability (DSC). The biological properties were assessed through the screening of prebiotic activity in Lactobacillus plantarum and Bifidobacterium animalis. The highest yield (58.82%) was achieved by using an alkaline thermal process, though the correspondent mannose content was low. The extract obtained by autolysis followed by a hydrothermal step resulted in the highest mannose content (59.19%). On the other hand, the extract obtained through the enzymatic hydrolysis displayed the highest prebiotic activity. This comparative study is expected to lay the scientific foundation for the obtention of well-characterized mannans from yeast, which will pave the way for their application in various fields.

3D bioprinting of modified mannan bioink for tissue engineering

This protocol details the steps for preparation of a recently developed bioink, named YM-MA, which is based on methacrylate anhydride-modified yeast mannan. A light-assisted 3D bioprinting is performed to analyze the printability of YM-MA bioink. We describe how cell experiments, animal models of subcutaneous implantation in a Sprague Dawley rat model, and nude mice are used to evaluate the cytocompatibility, histocompatibility, and chondrogenesis of YM-MA bioink. This protocol provides a versatile strategy to develop bioinks of polysaccharides with chemical modification sites such as hydroxyl group.

For complete details on the use and execution of this protocol, please refer to Huang et al. (2021).

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Preparation of a modified water-soluble polysaccharide polymer YM-MA bioink

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Optimized parameters for 3D printing of YM-MA bioink

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YM-MA bioink has good cytocompatibility and histocompatibility

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

An acidic polysaccharide from Oxalis corniculata L. and the preliminary study on its antioxidant activity

It has been reported that the aqueous extract from Oxalis corniculate has excellent pharmacological effects, but its polysaccharide as the major ingredient in the aqueous extract has not been reported. When the temperature of 50°C, ultrasonic power of 270 W, time of 25 min, solid to liquid ratio of 30 ml·g^-1 , the optimal O. corniculate polysaccharide (OCP) yield was 9.45%. The physicochemical properties indicated that OCP-3, as the major fraction of OCP, was an acidic polysaccharide with 31.5 kDa, and it mainly consisted of arabinose (47.83%), galacturonic acid (17.81%), and galactose (14.25%). In addition, OCP-3 displayed an excellent antioxidant activity in vitro, including scavenging free radical, anti-lipid peroxidation, and protecting plasmid DNA from oxidative damage. Meanwhile, OCP-3 significantly reduced the levels of malondialdehyde and protein carbonyl by significantly increasing the activity of superoxide dismutase, catalase, and glutathione peroxidase, which protected the HEK 293 cell and Caenorhabditis elegans from oxidative damage. All the results suggested that OCP-3 might be the major active ingredient of the aqueous extract from O. corniculate, and OCP-3 might be a potent antioxidant supplement in the food, cosmetics, and medical industries. PRACTICAL APPLICATIONS: Oxalis corniculate is a kind of wild vegetable and ethnomedicine, and it is widely distributed in temperate zones. Unfortunately, its utilization rate is low compared to its yield. Our research suggested that the polysaccharide of OCP-3 from O corniculate might be used as a potent antioxidant supplement in the food, cosmetics, and medical industries.

An Antioxidant Supplement Function Exploration: Rescue of Intestinal Structure Injury by Mannan Oligosaccharides after Aeromonas hydrophila Infection in Grass Carp (Ctenopharyngodon idella)

Mannan oligosaccharides (MOS) are a type of functional oligosaccharide which have received increased attention because of their beneficial effects on fish intestinal health. However, intestinal structural integrity is a necessary prerequisite for intestinal health. This study focused on exploring the protective effects of dietary MOS supplementation on the grass carp’s (Ctenopharyngodon idella) intestinal structural integrity (including tight junction (TJ) and adherent junction (AJ)) and its related signalling molecule mechanism. A total of 540 grass carp (215.85 ± 0.30 g) were fed six diets containing graded levels of dietary MOS supplementation (0, 200, 400, 600, 800 and 1000 mg/kg) for 60 days. Subsequently, a challenge test was conducted by injection of Aeromonas hydrophila for 14 days. We used ELISA, spectrophotometry, transmission electron microscope, immunohistochemistry, qRT-PCR and Western blotting to determine the effect of dietary MOS supplementation on intestinal structural integrity and antioxidant capacity. The results revealed that dietary MOS supplementation protected the microvillus of the intestine; reduced serum diamine oxidase and d-lactate levels (p < 0.05); enhanced intestinal total antioxidant capacity (p < 0.01); up-regulated most intestinal TJ and AJ mRNA levels; and decreased GTP-RhoA protein levels (p < 0.01). In addition, we also found several interesting results suggesting that MOS supplementation has no effects on ZO-2 and Claudin-15b. Overall, these findings suggested that dietary MOS supplementation could protect intestinal ultrastructure, reduce intestinal mucosal permeability and maintain intestinal structural integrity via inhibiting MLCK and RhoA/ROCK signalling pathways.

Characteristics of surface layer protein from Lactobacillus kefiri HBA20 and the role in mediating interactions with Saccharomyces cerevisiae Y8

In this study, the surface layer protein (SLP) from Lactobacillus kefiri HBA20 was characterized. The SLP was extracted by 5 M LiCl. The molecular mass of the SLP was approximately 64 kDa as analyzed via SDS-PAGE. The surface morphology and the adhesion potential of L. kefiri HBA20 in the absence and presence of SLP were measured by AFM. Moreover, the protein secondary structure was evaluated by using circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR), respectively. SLP had high β-sheet contents and low content of α-helix. Thermal analysis of SLP of Lactobacillus kefiri HBA20 exhibited one transition peak at 129.64 °C. Furthermore, SEM measurements were showed that after the SLP were removed from the cell surface, the coaggregation ability with Saccharomyces cerevisiae Y8 of the strain was significantly reduced. In conclusion, the SLP of Lactobacillus kefiri HBA20 has a stable structure and the ability of adhesion to yeast. Molecular docking study revealed that mannan bind with the hydrophobic residues of SLP. Our results will help further understanding of the new surface layer protein and the interaction between L. kefiri and S. cerevisiae.

Mannans and mannan oligosaccharides (MOS) from Saccharomyces cerevisiae - A sustainable source of functional ingredients

Sustainable industry practices and circular economy concepts encourage the transformation of production waste into by-products. Saccharomyces cerevisiae is widely used in fermentation industry worldwide, generating large amounts of spent yeast which is mainly directed to animal feed or discarded as waste. Instead of becoming and environmental problem, spent yeast can be directed to the extraction of valuable compounds such as mannans and mannan oligosaccharides (MOS). This review presents a compilation of the studies up to date regarding the different chemical, enzymatic, mechanical or physical processes addressed for mannans extraction and MOS production. Additionally, the existing studies on the chemical modification of mannans aimed to improve specific characteristics are also discussed. Finally, the more relevant bioactivities and potential applications of mannans, MOS and mannose are presented, together with products on the market containing these compounds.

Antioxidant activity of yeast mannans and their growth-promoting effect on Lactobacillus strains

Yeast mannans from Saccharomyces cerevisiae (123.2 kDa, 40.5 kDa and 21.3 kDa) were prepared. The scavenging abilities of Fe²⁺, OH˙, and O₂˙^- and protective capacities against lipid peroxidation and oxidative DNA damage increased with the reduction of the molecular weights of yeast mannans. The highest scavenging abilities of Fe²⁺, OH˙ and O₂˙^- (25.32%, 70.8%, and 61.5%) were observed with YM-90, and it showed an anti-lipid peroxidation capacity of 65.82%, which was much stronger than that of vitamin C (VC), with a thiobarbituric acid-reactive substance (TBARS) inhibition rate of 80.41%. However, the highest DPPH scavenging rate (88.7%) was exhibited by YM-30. In addition, the growth-promoting effect of yeast mannans on Lactobacillus strains was further confirmed, and a 54.2% increment of Lactobacillus plantarum ZWR5 cell viability was achieved by YM-90. The results indicated the potential industrial applications of this yeast mannan technology in therapeutic and nutraceutical production.

Preparation and antioxidant activity of phosphorylated polysaccharide from purple sweet potato

Purple sweet potato polysaccharide was extracted via hot water, and it was chemically modified by phosphorus oxychloride-pyridine to obtain phosphorylated polysaccharide from purple sweet potato (P-PPSP) with certain degrees of substitution. Furthermore, the structure and antioxidant activity in vitro of PPSP and phosphorylated derivative were compared. The result indicated that the phosphorylation modification product of polysaccharide from purple sweet potato could improve the scavenging effect on hydroxyl radical and superoxide anion of PPSP, significantly. It also could improve the anti-lipid peroxidation ability while fail to improve the reducing ability of PPSP.

Modified mannan for 3D bioprinting: a potential novel bioink for tissue engineering

3D bioprinting technology displays many advantages for tissue engineering applications, but its utilization is limited by veryfew bioinks available for biofabrication. In this study, a novel type of bioink, which includes three methacryloyl modifiedmannans, was introduced to 3D bioprinting for tissue engineering applications. Yeast mannan (YM) was modified by reactingwith methacrylate anhydride (MA) at different concentrations, and three YM derived bioinks were obtained, which weretermed as YM-MA-1, YM-MA-2 and YM-MA-3 and were distinguished with different adjusted methacrylation degrees. TheYM derived bioink displayed an advantage that the mechanical properties of its photo-cured hydrogels can be enhanced withits methacrylation degree. Hence, YM derived bioinks are fitted for the mechanical requirements of most soft tissueengineering, including cartilage tissue engineering. By selecting chondrocytes as the testing cells, well cytocompatibility of YM-MA-1, YM-MA-2 had been confirmed by CCK-8 method. Following photo-crosslinking and implantation into SD rats for 4 weeks, thein vivobiocompatibility of the YM-MA-2 hydrogel is acceptable for tissue engineering applications. Hence, YM-MA-2 was chosen for 3D bioprinting. Our data demonstrated that hydrogel products with designed shape and living chondrocytes have been printed by applying YM-MA-2 as the bioink carrying chondrocytes. After the YM-MA-2 hydrogel with encapsulated chondrocytes was implanted subcutaneously in nude mice for 2 weeks, GAG and COLII secretion was confirmed by histological staining in YM-MA-2-H, indicating that the YM derived bioink can be potentially applied to tissue engineering by employing a 3D printer of stereolithography.

Phosphorylation of polysaccharides: A review on the synthesis and bioactivities

Polysaccharides are macromolecules obtained from a wide range of sources and are known to have diverse biological activities. The biological activities of polysaccharides depend on their structure and physicochemical properties, including water solubility, monosaccharide composition, degree of branching, molecular structure, and molecular weight. Phosphorylation is a commonly used chemical modification method that improves the physicochemical properties of native polysaccharides, thus enhancing their biological activity, or even imparting novel biological activity. Therefore, phosphorylated polysaccharides have attracted increasing attention owing to their antioxidant, antitumor, antiviral, immunomodulatory, and hepatoprotective effects. In this review, we have discussed recent advances in the phosphorylation of polysaccharides, and the methods used for phosphorylation, structural characterization, and determination of biological activities, to provide a theoretical basis for the use of polysaccharides. The structure-activity relationship of phosphorylated polysaccharides and their use in the food and pharmaceutical industries needs to be further studied.

The characterization of optimal selenized garlic polysaccharides and its immune and antioxidant activity in chickens

The purpose of this study was to optimize modification conditions of selenized garlic polysaccharides (sGPS) and investigate its structural characterization, immune and antioxidant activities. Herein, selenized garlic polysaccharides (sGPS) were prepared using by HNO₃-Na₂SeO₃ selenylation method. And then modification conditions of sGPS were optimized through L₉ (3⁴) orthogonal test. The structural characterization of sGPS were identified by the Fourier-transform infrared (FT-IR), Solid-State nuclear magnetic resonance (NMR) spectra, X-ray diffraction (XRD) and thermogravimetric (TGA). The morphology of sGPS was detected using scanning electron microscope (SEM) and transmission electron microscope (TEM). In vivo investigation showed that sGPS significantly improved serum hemagglutination-inhibition (HI) antibody titers against Newcastle disease virus, enhanced secretory IgA (sIgA), IFN-γ, IL-2 secretion in jejunum and trachea irrigation compared with vaccine immunized control group. Furthermore, it showed that sGPS had some effects on the antioxidant activities in livers of chickens. In conclusion, the optimal modification conditions of sGPS were as follows: reaction temperature was 70 °C, the dosage of Na₂SeO₃ was 400 mg and reaction time was 6 h. The selenylation modification of garlic polysaccharides (GPS) could improve its immune and antioxidant activity in chickens.

Characterization of polysaccharides from Tetrastigma hemsleyanum Diels et Gilg Roots and their effects on antioxidant activity and H2O2-induced oxidative damage in RAW 264.7 cells

This work presents an investigation on the composition and structure of polysaccharides from the roots of Tetrastigma hemsleyanum (THP) and its associated antioxidant activity. It further explores the protective effect of THP on RAW264.7 cells against cytotoxicity induced by H₂O₂. Ion chromatography (IC) revealed that THP contained glucose, arabinose, mannose, glucuronic acid, galactose and galacturonic acid, in different molar ratios. Furthermore, gel permeation chromatography-refractive index-multiangle laser light scattering (GPC-RI-MALS) was employed to deduce the relative molecular mass (M_w) of the polysaccharide, which was 177.1 ± 1.8 kDa. Fourier transform infrared spectroscopy (FT-IR) and Congo red binding assay highlighted that the THP had a steady α-triple helix conformation. Similarly, assays of antioxidant activity disclosed that THP had reasonable concentration-dependent hydroxyl radical and superoxide radical scavenging activities, peroxidation inhibition ability and ferrous ion chelating potency, in addition to a significant 1,1-diphenyl-2-picrylhydrazyl radical scavenging capacity. Moreover, THP could protect RAW264.7 cells against H₂O₂-induced cytotoxicity by decreasing intracellular ROS levels, reducing catalase (CAT) and superoxide dismutase (SOD) activities, increasing lactate dehydrogenase (LDH) activity and increment in malondialdehyde (MDA) level. Data retrieved from the in vitro models explicitly established the antioxidant capability of polysaccharides from T. hemsleyanum root extracts.

Structure, preparation, modification, and bioactivities of β-glucan and mannan from yeast cell wall: A review

In order to solve the antibiotic resistance, the research on antibiotic substitutes has received an extensive attention. Many studies have shown that β-glucan and mannan from yeast cell wall have the potential to replace antibiotics for the prevention and treatment of animal diseases, thereby reducing the development and spread of antibiotic-resistant bacterial pathogens. β-Glucan and mannan had a variety of biological functions, including improving the intestinal environment, stimulating innate and acquired immunity, adsorbing mycotoxins, enhancing antioxidant capacity, and so on. The biological activities of β-glucan and mannan can be improved by chemically modifying its primary structure or reducing molecular weight. In this paper, the structure, preparation, modification, and biological activities of β-glucan and mannan were reviewed, which provided future perspectives of β-glucan and mannan.

Antioxidation, anti-inflammation and anti-fibrosis effect of phosphorylated polysaccharides from Pleurotus djamor mycelia on adenine-induced chronic renal failure mice

The mycelia polysaccharides (MPS) from Pleurotus djamor were prepared and purified by anion exchange column chromatography, and the phosphate content of phosphorylated MPS (PMPS) was 15.22 ± 0.37%. FT-IR spectra, HPLC and ¹H and ¹³C-NMR results showed the PMPS contained α-pyranose structure and the peak area percentage composition of galacturonic acid and glucose were 13.01% and 85.82%, respectively. Animal experiment investigated the antioxidant, anti-inflammation, anti-fibrosis effects of PMPS on kidney in adenine-induced chronic renal failure (CRF) mice. All results including serum biochemical indices, histopathological observation, qRT-PCR, western blotting, immunohistochemical staining manifested the kidney injury could be remitted by PMPS interventions. This experiment suggested that PMPS could remit CRF and other kidney injury related diseases as one kind of dietary supplements and functional foods without toxic side effects.

Autochthonous Yeast from Pork and Game Meat Fermented Sausages for Application in Meat Protection and Aroma Developing

Simple Summary

Yeasts are microorganisms presented naturally in meat products microbiota, which carry out an essential role in the maturation process of fermented sausages. The maturation of this type of product could be better controlled by the addition of a starter culture or a mix of strains that could standardize the process in diverse factories. Moreover, it would be favorable to find cultures that, not only conduct the curing process, but also present an added value such as the meat product protection (antioxidant capability and biocontrol activity). Yeasts also have an important role in the meat product aroma development. Therefore, it would be interesting to select a pleasant-aroma forming strain in order to elaborate a future starter culture for fermented sausage maturation.

Abstract

The wild yeast community was studied in fermented sausages from pork and game meat (deer and wild boar) during the maturation process from different curing rooms. Although the biotechnological importance of yeasts in the maturation process of pork sausages is known, there is a lack of information for sausage maturation involving game meat. A total of 123 yeasts were isolated and, by amplifying and sequencing of the ITS region, were classified in 14 species. Debaryomyces hansenii, Kazachstania servazzii, and Wickerhamomyces anomalus were isolated in both pork and game samples. The PCR-RAPD technique differentiated between 26 and 18 strains from pork and game meat sausages, respectively. The physicochemical parameters and their relationship with the yeast community were also studied. The antioxidant and anti-lipid peroxidation capability were analyzed and the 70% and 50% of the tested strains showed these abilities, respectively. Moreover, the biocontrol capability against mycotoxigenic molds was found in 19 strains, but better results were observed in game meat yeasts. On the other hand, almost 30% of strains produce a pleasant olfactory aroma, and volatile compounds associated with the yeast pathway metabolic during the maturation process have been characterized such as esters, aldehydes, fusel alcohols, etc. This study has allowed a better understanding of the biodiversity of this type of food, as well as selecting potential yeast strains for their future use as starters.

Biological Properties of Yeast-based Mannoprotein for Prospective Biomedical Applications

BACKGROUND

Natural products constitute more than half of all biomolecules lately being used in clinical settings. Mannoprotein derived from the yeast cell wall has found full biotechnological applications.

OBJECTIVE

This study was intended to investigate the antioxidant, anticancer, and toxicological properties of Kluyveromyces marxianus mannoprotein (KM).

METHODS

The KM extract was obtained through a sequence of operations, including centrifugation for cell isolation, precipitation with potassium citrate/sodium metabisulfite, and recovery and purification. Its antioxidant, growth inhibition, macrophage mitogenic, and toxic activities were evaluated for its future use in the biomedical field.

RESULTS

Significant inhibitory effects of KM were obtained on reactive species. It showed antiproliferative activity against HeLa (human cervical adenocarcinoma) and MCF-7 (human breast cancer) cell lines with no toxic effects on HUVECs (human umbilical vein endothelial cells). The in vitro model of CHO-K1 (Chinese hamster ovary) cell lines did not show the cytotoxic and genotoxic of KM. Moreover, it enhanced macrophage activity in terms of nitric oxide (NO) production and viability. No sign of acute toxicity was found in BALB/c mice, and body weight remained unchanged in guinea pigs over three months.

CONCLUSION

Comprehensive biological evaluations in this study are expected to expand the potential of KM as a natural material.

Polysaccharides catabolism by the human gut bacterium -Bacteroides thetaiotaomicron: advances and perspectives

In recent years, the degradation processes of polysaccharides by human gut microbiota are receiving considerable attention due to the discoveries of the powerful function of gut microbiota. Gut microbiota has developed a sensitive, accurate, and complex system for sensing, capturing, and degrading different polysaccharides. Among the gut microbiota, Bacteroides thetaiotaomicron, a representative species of Bacteroides, is considered as the best degrader of polysaccharides and a potential probiotic in pharmaceutical and food industries. Here, we summarize the degradation system of B. thetaiotaomicron and the degradation pathways of different polysaccharides by B. thetaiotaomicron. We also describe a technical route for investigating a specific polysaccharide degradation pathway by human gut bacteria. In addition, we also provide the future perspectives in the development of novel polysaccharides or oligosaccharides drugs, precision microbiology medicine, and personalized nutrition.

Neural Protective Effects of Millet and Millet Polyphenols on High-Fat Diet-Induced Oxidative Stress in the Brain

A high fat diet (HFD) is considered to be a risk factor for the development of dementia because it increases oxidative stress in the brain; thus, diets rich in antioxidants, such as polyphenols, may protect against oxidative damage. In this study, we explored the antioxidant activity and neural protective function of millet on high fat diet-induced oxidative stress in rat brains. Our results suggested that the intake of millet could alleviate oxidative stress in the hippocampus and downregulate the expression of the Alzheimer's disease (AD)-related genes amyloid precursor protein (App), tau, and γ-secretase. Furthermore, we extracted millet polyphenols and verified whether they play important roles during this process. The results showed that millet polyphenols significantly prevented H₂O₂-induced cell death of SH-SY5Y cells and decreased oxidative stress levels in cells. In addition, the expression levels of pro-inflammatory factors and AD-related genes were also downregulated by treatment with millet polyphenols. The above results indicated that millet and millet polyphenols could exert neural protective effects under high fat diet-induced oxidative stress by upregulating the expression of antioxidant enzymes and downregulating the expression of AD-related genes.

MYC regulates coelomocytes apoptosis by targeting Bax expression in sea cucumber Apostichopus japonicus

Myelocytomatosis viral oncogene (MYC), a multifunctional transcription factor, (TF) exerts various physiological and pathological effects on animals. AjMYC could induce coelomocyte apoptosis in Apostichopus japonicus, but the underlying molecular mechanism remains poorly understood. In this study, the promoter sequence of apoptosis regulator Bcl-2-associated X (Bax) was cloned by genomic walking. The AjBax promoter region spaning 1189 bp, containing several transcription factor binding sites, included four potential E-boxes (-1030 bp to -1019 bp, -785 bp to -774 bp, -570 bp to -559 bp, -100 bp to -89 bp), two P53 binding sites (-439 bp to -430 bp, -845 bp to -836 bp), and one NF-κB site (-191 bp to -182 bp). Transient transfection of EPC cells with 5'-deletion constructs linked to luciferase reporter revealed that the region -1189/+454 contributed importantly to the expression of the AjBax. In addition, the AjBax promoter was induced by LPS, PGN or MAN. The four potential MYC binding sites were cotransfected with AjMYC in EPC cell whether AjMYC could activate AjBax expression as a transcriptional factor. Only P1 (-1189/+454) fragment containing the first MYC binding site transfection increased the luciferase activity by 2.08-fold (p < 0.01) compared with the control. The first MYC binding site -1030/-1019 was essential to induce AjBax transcription. Further functional assay indicated that AjBax was significantly induced by 3.54-fold increase (p < 0.01) after AjMYC overexpression in sea cucumber coelomocytes. All our findings supported that AjMYC could regulate coelomocyte apoptosis by directly targeting AjBax expression in A. japonicus.

Protective effects of mung bean (Vigna radiata L.) and pea (Pisum sativum L.) against high-fat-induced oxidative stress

Hyperlipidemia is closely related to oxidative stress, and it has been proved that the intake of legumes can protect the body from chronic diseases related to oxidative stress. In this study, we investigated the protective effects of mung beans and peas against high-fat-diet-induced rats. It was found that, with 50% addition of mung beans or peas, the intake of mung beans and peas could significantly restore the levels of serum total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Liver staining also showed that high-fat diet (HFD) led to liver lesions, whereas whole-grain intake could significantly relieve these symptoms. Compared with the HFD group, the antioxidant defense system and antioxidant gene expression in administered legume groups improved markedly. Furthermore, the antioxidant activities of the two legume extracts were determined. Characterization showed that the ethanol extracts of mung beans and peas possessed high antioxidant activities, for their ability to scavenge ABTS and DPPH, reduce Fe3+ and their antilipid peroxidation capacity. Treatments with ethanol extracts at different doses could restore the levels of intracellular lipid, malondialdehyde, and antioxidant enzyme activities in oleic acid-induced HepG2 cells. All these results suggested that mung beans and peas or their extracts may be utilized as good candidates of natural antioxidant agents.

The antioxidant activities of balsam pear polysaccharide

The antioxidant activities of polysaccharide from balsam pear were studied. It was determined by gel permeation chromatography that the molecular weight distribution of purified polysaccharide was concentrated near 33582 Da. It indicated that the monosaccharide components were rhamnose, galacturonic acid, galactose, xylose and arabinose. Fourier transform infrared spectroscopy, nuclear magnetic resonance and Congo red experiments showed that there are C1, C2, C3, C5 links, and stable β-triple helix conformation in aqueous solution. It was found that polysaccharide had good scavenging effect on free radicals. So, balsam pear polysaccharide should be a potential antioxidant.

Antioxidant activity of Momordica charantia polysaccharide and its derivatives

Momordica charantia polysaccharide (MCP) was extracted by hot water and chemically modified to obtain phosphorylated Momordica charantia polysaccharide (P-MCP) with degree of substitution 0.12 and sulfated Momordica charantia polysaccharide (S-MCP) with degree of substitution 0.45. The sugar content of the three polysaccharides was determined by phenol sulfuric acid method, 74.0%, 68.1% and 59.8% respectively. The scavenging ability of three polysaccharides to superoxide anion, hydroxyl radical and DPPH radical, as well as their anti-lipid peroxidation and reduction ability were determined. The results showed that the antioxidant activity of polysaccharides varied with different chemical modifications.

Antioxidant activities of Sagittaria sagittifolia L. polysaccharides with subcritical water extraction

In the present study, orthogonal experiment (L₉ (3)⁴) was used to optimize the extraction process of Sagittaria sagittifolia L. polysaccharides (SSP) with subcritical water, and the antioxidant activities of polysaccharides were also investigated. The results showed that the optimum extraction conditions were obtained when pH, extraction temperature, extraction time, and liquid to solid ratio were 7, 170 °C, 16 min and 30:1 (mL/g), respectively. In addition, DPPH/ABTS radical scavenging rate and Fe³⁺ reducing power of polysaccharides exhibited a certain dose-effect relationship. Furthermore, both yield and antioxidant activities of polysaccharides with subcritical water extraction (SWE) were higher than traditional hot water extraction (HWE). The above results showed that SWE was an effective technique to extract and separate polysaccharides from Sagittaria sagittifolia L., which may be potentially applied in the related polysaccharides extraction.