Structure and immunomodulatory activity of Lentinus edodes polysaccharides modified by probiotic fermentation

Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.

Research advances on encapsulation of probiotics with nanomaterials and their repair mechanisms on intestinal barriers

Probiotics participate in various physiological activities and contribute to body health.However,their viability and bioefficacy are adversely affected by gastrointestinal harsh conditions,such as gastric acid,bile salts and various enzymes.Fortunately,encapsulation based on various nanomaterials shows tremendous potential to protect probiotics.In this review,we introduced some novel encapsulation technologies involving nanomaterials in view of predesigned stability and viability,selective adhesion,smart release and colonization,and efficacy exertion of encapsulated probiotics.Furthermore,the interactions between encapsulated probiotics and the gastrointestinal tract were summarized and analyzed,with highlighting the regulatory mechanisms of encapsulated probiotics on intestinal mechanical barrier,chemical barrier,biological barrier and immune barrier.This review would benefit the food and pharmaceutical industries in preparation and utilization of multifunctional encapsulated probiotics.

Fungi with potential probiotic properties isolated from Fuzhuan brick tea

Several of the fungal species associated with Fuzhuan brick tea(FBT)are considered as potential probiotics,but few studies have investigated the probiotic properties of these fungi.Here,we isolated 18 fungal strains from two types of FBT and identified these strains based on internal transcribed spacer(ITS)fragment sequence similarity to reference strains(sequence similarity>98%).Of the 18 strains,10 tolerated simulated human digestive conditions for sufficient periods in vitro:pH 2-3,0.3%-0.5%(m/V)bile salts,and artificial gastrointestinal juices.We then measured the antimicrobial activity of the remaining 10 strains against 5 enteropathogenic bacteria and tested the bacteriostatic effects of the thalli and fermentation broth extracts.Of the 6 strains with strong bacteriostatic effects,we eliminated Eurotium cristatum S-9 due to its low hydrophobicity of(26.12±0.35)%.Finally,2 exhibited good adhesion abilities to human cells(>100%).Notably,2 strains can survive in vivo,because they can be isolated from C57BL/6 mice feces.Thus,2 strains,Aspergillus cristatus H-1 and A.cristatus H-5,are herein identified as promising candidate probiotic strains.It may be put forward a novel research focus on evaluating potential probiotic fungi from FBT.

Virulence changes in Vibrio parahaemolyticus during the freezing of Penaeus chinensis

Although Vibrio parahaemolyticus has become the most common pathogen in fresh and frozen seafood,its virulence changes have often been ignored during the processing of seafood.To investigate these potential risks,we used frozen Penaeus chinensis as examples,and the most virulent factors of V.parahaemolyticus,including amounts,viable but nonculturable(VBNC)status,toxins TDH and TRH,and virulence genes tdh and trh,were determined.Bacterial quantities were signifi cantly reduced during drain and sprinkling phases,but caused by different factors.By SYTO9 and PI staining showed that washing was the main reason for the bacterial reduction at the drain phase,while the strain entering VBNC state was another reason at sprinkling phase.Their hemolysis toxicity,produced by TDH and TRH,became stronger after inoculation on shrimp,and could be detected throughout the process.Moreover,tdh and trh also exhibited trends similar to that of the hemolysis toxicity test.tdh was almost to a two-fold expression level during ice-glazing phase,while trh only express at a low level,less than half of the expression level before inoculation.These results demonstrated that the strains were not dead during freezing process,but became VBNC cells,which still produced and accumulated toxins,especially TDH,the most virulent factor.

Insights into high-efficient removal of tetracycline by a codoped mesoporous carbon adsorbent

Adsorbents with simple preparation and high surface area have become increasingly prevalent for the removal of organic contaminants.Herein,a carbon nanoplate codoped by Co and N elements with abundant ordered mesoporous(Co/N-MCs)was applied as an adsorbent for tetracycline removal.Taking integrated advantages of ordered mesopores on carbon-based structures and N-doping inducing the strengthenedπ–πdispersion and generation of pyridinic N,as well as cobaltic nanoparticles embedded in carbon nanoplates,the Co/N-MCs was tailored for high efficiently absorbing tetracycline viaπ-πinteraction,Lewis acid-base interaction,metal complexation and electrostatic attraction.The Co/N-MCs had the advantages of high surface area,porous structure,plenty adsorption sites,and easy separation.As such,the as-prepared Co/N-MCs adsorbents significantly enhanced tetracycline removal performance with a maximum adsorption capacity of 344.83 mg·g^(-1) at pH 6 and good reusability,which was finally applied to removal tetracycline from tap water sample.Furthermore,the adsorption process towards tetracycline hydrochloride could be well attributed to the pseudo-second-order kinetic and Langmuir isotherm models.Compared with traditional carbon-based adsorbents,it owns a simpler synthesis method and a higher adsorption capacity,as well as it is a promising candidate for water purification.

Adenosine cyclic phosphate with ultrasonic-assisted pectinase extraction alleviated allergic reactions in RBL-2H3 through inhibiting the influx of intracellular Ca^(2+)

Jujube contains abundant cyclic adenosine monophosphate(cAMP)and the ultrasonic-assisted pectinase extraction(UAPE)conditions for obtaining the maximum cAMP yield from jujube were optimized.Orthogonal array design was applied to evaluate the effects of 4 variables by UAPE on cAMP yield.The results showed that the optimal cAMP yield(783.0μg/g)was derived at ratio of liquid to solid 5 mL/g,ratio of pectinase to raw material 1.5%,time 60 min and temperature 40℃.Moreover,the effect of cAMP on the anti-allergic function of action induced by immunoglobulin E(IgE)and its meschanism was investigated through establishing the sensitized cell model in rat basophilic leukemia(RBL-2 H3)cells using dinitrophenylated(DNP)-bovine serum albumin(BSA)-IgE.The results showed that cAMP interfered with sensitized cells,effectively inhibited the occurrence of basophil degranulation in dose dependence,and significantly reduced the activity ofβ-hexosamindase(β-hex),at the optimal concentration of 50μg/mL.The level of anti-inflammatory factor interleukin-10(IL-10)was promoted and the content of pro-inflammatory factor tumor necrosis factor-α(TNF-α)was suppressed by cAMP.In addition,influx of intracellular Ca^(2+) was repressed effectively.Our results demonstrate that jujube cAMP regulated the cytokine balance in the allergy pathway through blocking the influx of extracellular Ca^(2+),with the prevention of allergy symptoms.

Selective removal of heavy metal ions in aqueous solutions by sulfide-selector intercalated layered double hydroxide adsorbent

Remaining largely under-appreciated, a majority of metal ion sorbents are limited in their target selectivity. In this work, a 3D sulfide intercalated NiFe-layered double hydroxide (NFL-S) hierarchical sorbent has been synthesized for selective heavy metal removal. The intercalation of sulfurated groups in the interlayer of the layered double hydroxide (LDH) nanosheets endows NFL-S as a selective heavy metal ion filter;the selectivity of NFL-S for heavy metals is in the order of Pb^2+> Cu^2+≥ Zn^2+> Cd^2+> Mn^2+, and NFL-S has high kd values for Pb2+(~10^6 mL/g) and Cu2+(~10^5 mL/g). Scanning electron microscopy. X-ray photoelectron spectroscopy and powder X-ray diffraction were used to analyze the composition of the as-prepared nanoadsorbent. The selective adsorption behavior was systematically studied using batch experiments, and the performance was evaluated through kinetic and isotherm studies. Moreover, the adsorption mechanism of heavy metals by NFL-S through surface complexation was also investigated, which shows great potential for water decontamination.

Contribution of non-Saccharomyces yeasts to aroma-active compound production,phenolic composition and sensory profile in Chinese Vidal icewine

To acquire candidate non-Saccharomyces strains for preparation of high-quality Vidal icewine,11 representative indigenous non-Saccharomyces strains were selected for analyzing their production of organic acids,phenolic compounds,aroma-active compounds and evaluating their sensory profile in Vidal juice.The results showed that the contents of organic acids in the wines were controlled and balanced well by the non-Saccharomyces strains as well as polyphenol concentrations were well improved during the fermentation.The strains differed from each other in their ability to produce aroma compounds,causing diversity and complexity of aroma characteristics in wine.Fermentation by Saccharomycopsis crataegensis YC30(Sc)and Hanseniaspora uvarum QTX22(Hu)could enhance the sweet and floral notes in Vidal icewine,especially Sc,which has never been reported before.It can not only enrich the aroma categories,but also increase the content ofδ-decalactone,γ-decalactone,ethyl isobutyrate,ethyl butyrate,phenethyl acetic acid,etc.The evaluation and optimization of non-Saccharomyces yeast strains could provide theoretical basis for the improvement of ice wine quality,and supply new ideas and strategies for the brewing of ice wine.

Effects of Tibetan kefir grain fermentation on the physicochemical properties,phenolics,enzyme activity,and antioxidant activity of Lycium barbarum(Goji berry)juice

This study describes the changes in the microbial growth,physicochemical properties,phenolics,enzyme activity,and antioxidant activity of Goji berry juice during fermentation with Tibetan kefir grains(TKG).The results showed that TKG grew well in Goji berry juice,and yeasts were dominant in the later period of fermentation(5.20×10^(8) CFU/mL).The main fungal genus of TKG and fermented Goji berry juice(24,48,and 72 h)was Kazachstania stably.The relative abundance of Lactobacillus in Goji berry juice decreased from 92.05%to 33.11%after 72 h-fermentation,while that of Acetobacter increased to 66.81%.In addition,72 h-fermentation led to the consumption of 82.55%of total sugar and 93.90%of reducing sugar,as well as dramatic changes in organic acids.The main volatile substances changed from aldehydes(61.98%)to alcohols(55.24%)and esters(38.54%).The content of total soluble flavonoids(STFC)in Goji berry juice was significantly increased from 42.28 mg RE/100 mL to 85.69 mg RE/100 mL after complete fermentation(p<0.01).Furthermore,16 flavonoids,eight phenolic acids,one phenolic acid derivative,and two coumarins were identified by HRLC-ESI-MS/MS.α-Amylase and xylanase were primarily responsible for the release of flavonoids(mangiferin,rutin,hyperoside,isoquercitrin,and quercetin)during fermentation,thus significantly enhancing the reducing power and OH⋅scavenging activity of Goji berry juice.

Effects of secondary fermentation of four in-bottle Saccharomyces cerevisiae strains on sparkling cider sensory quality

In this study,the first fermentation of Fuji apple juice was carried out using Saccharomyces cerevisiae WLS21 and continued a second fermentation using S.cerevisiae HYJ1,HYJ2,PE2,and Y41 in sealed bottles after adjusting the sugar level.The physicochemical indexes,aromas,and sensory characteristics of four sparkling ciders were analyzed.The results revealed that HYJ2 produced the highest amount of ethanol and Y41 had the highest pressure in the bottle at the end of fermentation.Y41 produced the highest citric and succinic acids and HYJ1 produced higher fumaric acid and total volatiles.HYJ1 cider had an obvious herbaceous odor,and Y41 cider had a fruity character.Sixty-seven volatiles were detected from four sparkling ciders(55 fermentative and 12 non-fermentative aromas).Esters(EEFAs and HAAs)were the main volatile aroma family produced during secondary fermentation,and terpenes contributed the most to fruity odor.Based on univariate(ANOVA)and multivariate analysis of variance(PLS-DA)screening of four cider significant variables,13 volatiles with variable predictive importance(VIP)≥1 were identified.PLSR analysis revealed that 2-methylbutyl acetate,ethyl heptanoate,2-methyl-1-butanol,nonanal,2-nonanone,β-damascenone,and linalool were potential volatile markers for OAV>1.

Microbial diversity associated with Tibetan kefir grains and its protective effects against ethanol-induced oxidative stress in HepG2 cells

Tibetan kefir grains (TKGs) and their products are multi-functional health supplements. This study aimed to explore the diversity of microorganisms in Tibetan kefir grains (TKGs) and the protective effect of isolates on ethanol-treated HepG2 cells. Metagenomic sequencing showed that Lactobacillus Kefiranofaciens was the most abundant bacterial taxon, while Kluyveromyces marxianus was the most abundant fungal taxum in TKGs. Thirteen isolates belonging to the genera Lactobacillus (3), Fructobacillus (1), Lactococcus (1), Pediococcus (1), Acetobacter (3), and Kluyveromyces (4), were obtained by cultivation methods. KEGG pathway analysis revealed that K. marxianus contributed four KEGG pathways related to hepatic disease. LC-MS analysis revealed CFEs are rich sources of peptides amino acids, lipids and amino acids. Cell-free extracts (CFEs) prepared from K. marxianus protected HepG2 cells from ethanol-induced injury. Treatment with CFEs from isolates YG-4 and YK-6 significantly increased cell viability and reduced ethanol cytotoxicity. Also, YG-4 and YK-6 decreased reactive oxygen species, malondialdehyde and alanine aminotransferase, increased superoxide dismutase and catalase, and reduced apoptosis and loss of potential in mitochondria. In addition, CFEs, especially YG-4-derived CFEs, decreased ethanol-induced inflammatory cytokines (IL-6, IL-17 and TNF-α), while YG-4 and YK-6 CFEs upregulated the regulatory cytokine IL-4. Thus, YG-4 had the most significant anti-inflammatory effects by reducing ethanol-induced oxidative stress. These isolates’ properties may provide new avenues to use K. maxianus in alcoholic liver disease.

Improving microbiological and physicochemical properties of fresh-cut apples using carvacrol emulsions

The cut or sliced form of apples are more prone to chemical deterioration and microbial growth.In this work,quality changes(physicochemical properties,sensory quality,and microbial growth)of fresh-cut apples stored at 4℃ for 15 days were studied after immersion treatment(water,biopolymer complex;free carvacrol,and carvacrol emulsion).Whey protein isolate/high methoxyl pectin-based carvacrol emulsions effectively delayed the browning process and reduced variation in chemical quality compared to other groups.Apples treated with carvacrol emulsions were more favored by panelists at the middle-and late-stages of storage.Additionally,the presence of carvacrol emulsions improved microbial safety,as demonstrated by the number of viable bacteria(<6 log CFU/g)and yeast and mold(<5 log CFU/g)after 15 d of storage.16 S rRNA Gene Sequencing was used to identify the bacterial species responsible for the spoilage of fresh-cut apples.These results show that carvacrol emulsions are a potential preservation alternative for fresh-cut apples.