Lacticaseibacillus rhamnosus Fmb14 prevents purine induced hyperuricemia and alleviate renal fibrosis through gut-kidney axis.

Hyperuricemia is a critical threat to human health, and conventional medical treatment only aims to treat acute gouty arthritis. Purine diet-mediated chronic hyperuricemia and related syndromes are neglected in clinical therapeutics. In this study, the prevention ability of Lacticaseibacillus rhamnosus Fmb14, screened from Chinese yogurt, was evaluated in chronic purine-induced hyperuricemia (CPH) mice. After 12 weeks of Fmb14 administration, serum uric acid (SUA) in CPH mice decreased by 36.8 %, from 179.1 to 113.2 µmol/L, and the mortality rate decreased from 30 % to 10 %. The prevention role of Fmb14 in CPH was further investigated, and the reduction of uric acid by Fmb14 was attributed to the reduction of XOD (xanthine oxidase) in the liver and URAT1 in the kidney, as well the promotion of ABCG2 in the colon. Fmb14 administration Increased ZO-1 and Occludin expression in the colon and decreased fibrosis degree in the kidney indicated that Fmb14 administration had preventive effects through the gut-kidney axis in CPH. In specific, Fmb14 administration upregulated the diversity of gut microbiota, increased short-chain fatty acids (SCFA) by 35 % in colon materials and alleviated the inflammatory response by reducing biomarkers levels of IL-1ß, IL-18 and TNF-α at 11.6 %, 21.7 % and 26.5 % in serum, compared to CPH group, respectively. Additionally, 16 S rRNA sequencing showed 31.5 % upregulation of Prevotella, 20.5 % and 21.6 % downregulation of Ruminococcus and Suterella at the genus level, which may be a new gut microbial marker in hyperuricemia. In conclusion, Fmb14 ameliorated CPH through the gut-kidney axis, suggesting a new strategy to prevent hyperuricemia.

Combating biofilms of foodborne pathogens with bacteriocins by lactic acid bacteria in the food industry.

Most foodborne pathogens have biofilm-forming capacity and prefer to grow in the form of biofilms. Presence of biofilms on food contact surfaces can lead to persistence of pathogens and the recurrent cross-contamination of food products, resulting in serious problems associated with food safety and economic losses. Resistance of biofilm cells to conventional sanitizers urges the development of natural alternatives to effectively inhibit biofilm formation and eradicate preformed biofilms. Lactic acid bacteria (LAB) produce bacteriocins which are ribosomally synthesized antimicrobial peptides, providing a great source of nature antimicrobials with the advantages of green and safe properties. Studies on biofilm control by newly identified bacteriocins are increasing, targeting primarily onListeria monocytogenes, Staphylococcus aureus, Salmonella, and Escherichia coli. This review systematically complies and assesses the antibiofilm property of LAB bacteriocins in controlling foodborne bacterial-biofilms on food contact surfaces. The bacteriocin-producing LAB genera/species, test method (inhibition and eradication), activity spectrum and surfaces are discussed, and the antibiofilm mechanisms are also argued. The findings indicate that bacteriocins can effectively inhibit biofilm formation in a dose-dependent manner, but are difficult to disrupt preformed biofilms. Synergistic combination with other antimicrobials, incorporation in nanoconjugates and implementation of bioengineering can help to strengthen their antibiofilm activity. This review provides an overview of the potential and application of LAB bacteriocins in combating bacterial biofilms in food processing environments, assisting in the development and widespread use of bacteriocin as a promising antibiofilm-agent in food industries.

Promoted Spore Formation of Bacillus amyloliquefaciens fmbJ by its Secondary Metabolite Bacillomycin D Coordinated with Mn2.

In Bacillus, the spore formation process is associated with the synthesis and release of secondary metabolites. A large number of studies have been conducted to systematically elucidate the pathways and mechanisms of spore formation. However, there are no studies have explored the relationship between secondary metabolites and spores. In this study, we investigated the relationship between its secondary metabolite bacillomycin D (BD) and spores using the simpler dipicolonic acid fluorimetry assay for spore counting in Bacillus amyloliquefaciens fmbJ. Our results showed that BD could promote the spore formation of B. amyloliquefaciens fmbJ and had a synergistic effect with certain concentrations of Mn2+. When 15.6 mg/L of BD and 1 mM of Mn2+ were added, the number of fmbJ spores increased from 1.42 × 108 CFU/mL to 2.02 × 108 CFU/mL after 36 h of incubation. The expressions of spore formation (kinA, kinB, kinC, kinD, kinE and spo0A) and Mn-related genes (mntA, mntH, mneS, mneP) were studied by RT-PCR. The results indicated that BD and Mn2+ promoted the spore formation of fmbJ by stimulating the transcription of kinB, kinD and increasing the influence of spo0F-spo0A phosphorylation transmission. This study provided a new idea to improve the spore production of B. amyloliquefaciens and laid the foundation for its industrial production. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01026-9.

Low-energy X-ray inactivation of Listeria monocytogenes in mono-/co-culture biofilms with Pseudomonas fluorescens on food contact surfaces.

This study assessed the inactivation kinetics of 150 keV low-energy X-ray on mono-/co-culture biofilms of Listeria monocytogenes and Pseudomonas fluorescens on three different food-contact-surfaces (polyethylene, acrylic, and stainless steel). The results indicated that the level of biofilm formation of mono-/co-cultures of L. monocytogenes and P. fluorescens was the highest on acrylic. The mono-culture L. monocytogenes biofilm cells exhibited higher resistance to the low-energy X-rays than the corresponding mono-culture P. fluorescens biofilm cells, regardless of surface types. Furthermore, co-culture had enhanced the resistance of both P. fluorescens and L. monocytogenes biofilm cells to the low-energy X-ray. Two kinetic models for the inactivation process were investigated, including (i) Linear model and (ii) Weibull model. Based on R2, RMSE and AIC analysis, the Weibull model was superior in fitting the inactivation curves of low-energy X-ray on L. monocytogenes in mono-/co-culture biofilms with P. fluorescens. For mono-culture biofilms, the irradiation achieved the tR1 value (derived from the Weibull model, i.e., the dose required for the first 1-log reduction) of 46.36-50.81 Gy for L. monocytogenes and the tR1 value of 25.61-31.33 Gy for P. fluorescens. For co-culture biofilms, higher tR1 values for L. monocytogenes (59.54-70.77 Gy) and P. fluorescens (32.73-45.13 Gy) were yielded than those for their individual counterparts in mono-culture biofilm.

Iturin A Induces Resistance and Improves the Quality and Safety of Harvested Cherry Tomato.

The soft rot disease caused by Rhizopus stolonifer is an important disease in cherry tomato fruit. In this study, the effect of iturin A on soft rot of cherry tomato and its influence on the storage quality of cherry tomato fruit were investigated. The results showed that 512 µg/mL of iturin A could effectively inhibit the incidence of soft rot of cherry tomato fruit. It was found that iturin A could induce the activity of resistance-related enzymes including phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), glucanase (GLU), and chitinase (CHI), and active oxygen-related enzymes including ascorbate peroxidases (APX), superoxide dismutases (SOD), catalases (CAT), and glutathione reductase (GR) of cherry tomato fruit. In addition, iturin A treatment could slow down the weight loss of cherry tomato and soften the fruit. These results indicated that iturin A could retard the decay and improve the quality of cherry tomato fruit by both the inhibition growth of R. stolonifera and the inducing the resistance.

ß-Glucan Extracted from Highland Barley Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis in C57BL/6J Mice.

Inflammatory bowel disease (IBD), which significantly affects human health, has two primary presentations: Crohn's disease and ulcerative colitis (UC). Highland barley is the most common food crop for Tibetans and contains much more ß-glucan than any other crop. Highland barley ß-glucan (HBBG) can relieve the gastrointestinal dysfunction and promote intestines health. This study aimed to evaluate whether HBBG can relieve UC in mice. A mouse model of UC was established by adding 2% dextran sulfate sodium (DSS) to drinking water for 1 week. UC was alleviated after the introduction of the HBBG diet, as indicated by reductions in the disease activity index (DAI) score, histopathological damage, and the concentration of colonic myeloperoxidase (MPO), along with an improvement in colonic atrophy. Furthermore, we found that HBBG can increase the relative transcriptional levels of genes encoding ZO-1, claudin-1, occludin, and mucin2 (MUC2), thereby reducing intestinal permeability. Additionally, HBBG maintained the balance of proinflammatory and anti-inflammatory cytokines and modulated the structure of the intestinal flora.

Metabolic characterisation of eight Escherichia coli strains including "Big Six" and acidic responses of selected strains revealed by NMR spectroscopy.

The metabolic diversity of Escherichia coli strains (non-pathogenic E. coli ATCC 25922, and pathogenic E. coli O157:H7, O26:H11, O45:H2, O103:H11, O111, O121:H19, and O145) was tested using nuclear magnetic resonance. Based on two representative two-dimensional 1H-13C spectra, 38 metabolites were identified in E. coli intracellular samples. Principal component analysis indicated that metabolites including lysine, arginine, α-ketoglutaric acid, adenosine, and fumaric acid were responsible for the separation of E. coli ATCC 25922. Relatively large metabolic differences between ATCC 25922 and the pathogenic strains were recoded. The most varied pairwise group (ATCC 25922 vs. O26:H11) was further analysed. The screened metabolites and enrichment pathway tests revealed different amino acid metabolism and higher requirement for energy production in the pathogenic strains. The acidic responses of the selected strains were further tested. The in vitro and in vivo inactivation kinetics, morphological changes, and protein leakage showed higher acid tolerance of E. coli O26:H11. Metabolic analysis of the two strains under acidic stress revealed alternative metabolites and pathways in the two groups. Pathogenic O26:H11 was characterised by higher energy production and amino acid metabolism (lysine and glutamic acid). Real-time PCR tests confirmed that glutamic acid dependent decarboxylase/antiporter system was the major acid resistance mechanism.

Effects of the colonization sequence of Listeria monocytogenes and Pseudomonas fluorescens on survival of biofilm cells under food-related stresses and transfer to salmon.

This study evaluated how the colonization sequence of Listeria monocytogenes and Pseudomonas fluorescens affects biofilm formation and biofilm cell response to food-related stress (desiccation or disinfection) as well as the transferability of L. monocytogenes to salmon products. The results showed that the colonization sequence did not affect the population of dual species biofilms. Furthermore, survival number of L. monocytogenes was 0.8 log CFU/cm2 higher when P. fluorescens was the first colonizer during desiccation or disinfectant treatment in comparison with dual-species biofilms with other colonization sequences. A lower transfer rate of L. monocytogenes biofilm cells from dual-species biofilms was observed as compared to single species biofilms. In particular, L. monocytogenes cells detached at a slower rate during transfer to 10 slices of salmon from dual-species biofilms first established by P. fluorescens. Confocal images revealed more exopolysaccharide production in dual-speciesbiofilms first established by P. fluorescens than in biofilms generated via other sequences. These results indicate that preexisting P. fluorescens biofilms on stainless steel can enhance resistance of L. monocytogenes to desiccation and disinfection, although this setup decreased the transfer rate of L. monocytogenes to salmon slices. Thus, this study highlights the risk of L. monocytogenes contamination in pre-formed Pseudomonas biofilms at salmon processing facilities.

Salmonella detection in powdered dairy products using a novel molecular tool.

In this study, we developed a rapid, specific, and sensitive loop-mediated isothermal amplification technique combined with a lateral flow dipstick (LAMP-LFD) method to detect Salmonella targeting the siiA gene in powdered infant formula (PIF). The specificity of the detection method (LAMP-LFD) approached 100% using 21 Salmonella and 31 non-Salmonella bacterial strains. This detection method exhibited high sensitivity limits for pure cultures at 3.7 cfu/mL and in PIF at 2.2 cfu/g without enrichment. To evaluate the applicability of the LAMP-LFD method, we detected 60 positive PIF samples and 20 negative PIF samples. The results showed that the method of LAMP-LFD had a high diagnostic specificity of 100% for detection of Salmonella in PIF. To reduce incidence of LAMP contamination, we applied propidium monoazide (PMA) to eliminate carryover contamination of LAMP. At the same time, we found that PMA does not affect observation of LFD for measurement of LAMP signal. The results verified that the method of LAMP-LFD targeting the siiA gene is rapid, accurate, and sensitive for Salmonella detection in PIF, and that PMA shows great potential to be widely used to eliminate the amplicon contamination risk generated by the highly sensitive LAMP reaction in the detection process.

Acid modified attapulgite loaded with bacillomycin D for mold inhibition and mycotoxin removal.

Molds and mycotoxins pose severe threats to health. Bacillomycin D (BD) can effectively inhibit mold growth. Attapulgite (ATP) can provide a good carrier for antimicrobial agents. Natural ATP was acid-modified to obtain H-ATP. It was used to load BD to obtain a novel composite material (H-ATP-BD). The results showed H-ATP had better adsorption performance than ATP. BD was adsorbed up to 93.13 % by adding 30 mg H-ATP and stirring at 40 ℃ for 120 min. Fourier transform infrared spectra (FTIR), size and zeta potential, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results confirmed successful loading of BD onto H-ATP. The composite showed good inhibition of Aspergillus and adding 0.6 % H-ATP-BD composite was effective in removing 89.06 % of aflatoxin B1 (AFB1) at 50 °C. Model fitting indicated that AFB1 removal was a spontaneous exothermic reaction. This research will lay the foundation for the development of efficient and green antimicrobial and toxin-reducing materials.

Broccoli Improves Lipid Metabolism and Intestinal Flora in Mice with Type 2 Diabetes Induced by HFD and STZ Diet.

Globally, type 2 diabetes (T2DM) is on the rise. Maintaining a healthy diet is crucial for both treating and preventing T2DM.As a common vegetable in daily diet, broccoli has antioxidant, anti-inflammatory and anticarcoma physiological activities. We developed a mouse model of type 2 diabetes and carried out a systematic investigation to clarify the function of broccoli in reducing T2DM symptoms and controlling intestinal flora. The findings demonstrated that broccoli could successfully lower fasting blood glucose (FBG), lessen insulin resistance, regulate lipid metabolism, lower the levels of TC, TG, LDL-C, and MDA, stop the expression of IL-1ß and IL-6, and decrease the harm that diabetes causes to the pancreas, liver, fat, and other organs and tissues. Furthermore, broccoli altered the intestinal flora's makeup in mice with T2DM. At the genus level, the relative abundance of Allobaculum decreased, and that of Odoribacter and Oscillospira increased; At the family level, the relative abundances of Odoribacteraceae, Rikenellaceae and S24-7 decreased, while the relative abundances of Erysipelotrichaceae and Rikenellaceae increased.

Preparation and characterization of nisin-loaded chitosan nanoparticles functionalized with DNase I for the removal of Listeria monocytogenes biofilms.

Listeria monocytogenes biofilms represent a continuous source of contamination, leading to serious food safety concerns and economic losses. This study aims to develop novel nisin-loaded chitosan nanoparticles (CSNPs) functionalized with DNase I and evaluate its antibiofilm activity against L. monocytogenes on food contact surfaces. Nisin-loaded CSNPs (CS-N) were first prepared by ionic cross-linking, and DNase I was covalently grafted on the surface (DNase-CS-N). The NPs were subsequently characterized by Zetasizer Nano, transmission electron microscopy, Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). The antibiofilm activity of NPs was evaluated against L. monocytogenes on polyurethane (PU). The DNase-CS-N was fabricated and characterized with quality attributes (particle size-427.0 ± 15.1 nm, polydispersity [PDI]-0.114 ± 0.034, zeta potential-+52.5 ± 0.2 mV, encapsulation efficiency-46.5% ± 3.6%, DNase conjugate rate-70.4% ± 0.2). FT-IR and XRD verified the loading of nisin and binding of DNase I with chitosan. The DNase-CS-N caused a 3 log colony-forming unit (CFU)/cm2 reduction of L. monocytogenes biofilm cells, significantly higher than those in CSNPs (1.4 log), CS-N (1.8 log), and CS-N in combination with DNase I (2.2 log) treatment groups. In conclusion, nisin-loaded CSNPs functionalized with DNase I were successfully prepared and characterized with smooth surface and nearly spherical shape, high surface positive charge, and good stability, which is effective to eradicate L. monocytogenes biofilm cells on food contact surfaces, exhibiting great potential as antibiofilm agents in food industry. PRACTICAL APPLICATION: Listeria monocytogenes biofilms are a common safety hazard in food processing. In this study, novel nanoparticles were successfully constructed and are expected to be a promising antibiofilm agent in the food industry.

Electroacoustic Responsive Cochlea-on-a-Chip.

Organ-on-chips can highly simulate the complex physiological functions of organs, exhibiting broad application prospects in developmental research, disease simulation, as well as new drug research and development. However, there is still less concern about effectively constructing cochlea-on-chips. Here, a novel cochlear organoids-integrated conductive hydrogel biohybrid system with cochlear implant electroacoustic stimulation (EAS) for cochlea-on-a-chip construction and high-throughput drug screening, is presented. Benefiting from the superior biocompatibility and electrical property of conductive hydrogel, together with cochlear implant EAS, the inner ear progenitor cells can proliferate and spontaneously shape into spheres, finally forming cochlear organoids with good cell viability and structurally mature hair cells. By incorporating these progenitor cells-encapsulated hydrogels into a microfluidic-based cochlea-on-a-chip with culture chambers and a concentration gradient generator, a dynamic and high-throughput evaluation of inner ear disease-related drugs is demonstrated. These results indicate that the proposed cochlea-on-a-chip platform has great application potential in organoid cultivation and deafness drug evaluation.

Biofilm formation in food processing plants and novel control strategies to combat resistant biofilms: the case of Salmonella spp.

Salmonella is one of the pathogens that cause many foodborne outbreaks throughout the world, representing an important global public health problem. Salmonella strains with biofilm-forming abilities have been frequently isolated from different food processing plants, especially in poultry industry. Biofilm formation of Salmonella on various surfaces can increase their viability, contributing to their persistence in food processing environments and cross-contamination of food products. In recent years, increasing concerns arise about the antimicrobial resistant and disinfectant tolerant Salmonella, while adaptation of Salmonella in biofilms to disinfectants exacerbate this problem. Facing difficulties to inhibit or remove Salmonella biofilms in food industry, eco-friendly and effective strategies based on chemical, biotechnological and physical methods are in urgent need. This review discusses biofilm formation of Salmonella in food industries, with emphasis on the current available knowledge related to antimicrobial resistance, together with an overview of promising antibiofilm strategies for controlling Salmonella in food production environments.

Inactivation effect of low-energy X-ray irradiation against planktonic and biofilm Pseudomonas fluorescens and its antibacterial mechanism.

Pseudomonas fluorescens is a well-known biofilm former on food contact surfaces and can cause severe cross-contamination in food processing premises. This study aimed to determine the inactivation effect of low-energy X-ray on P. fluorescens planktonic cells in phosphate-buffered saline solution (PBS) and P. fluorescens biofilm cells on food-contact-surface (stainless steel). The results demonstrated that low-energy X-ray irradiation at 125 Gy inactivated 4.60 log CFU/mL and 4.21 log CFU/cm2 for P. fluorescens planktonic and biofilm cells, respectively. Based on Weibull model, low-energy X-ray achieved tR1 values of 14.8 Gy and 11.6 Gy for P. fluorescens planktonic and biofilm cells, respectively. Apart from cell inactivation, the irradiation also led to the destruction of extracellular polymeric substances (EPS) structure. Low-energy X-ray irradiation markedly damaged bacterial glucose uptake system and resulted in part loss of bacterial membrane potential and integrity. These results suggested the potential of the low-energy X-ray for inactivating P. fluorescens biofilm cells and removing EPS in food industry.

The protective effects of sulforaphane on high-fat diet-induced metabolic associated fatty liver disease in mice via mediating the FXR/LXRα pathway.

Metabolic-associated fatty liver disease (MAFLD) is becoming the key factor in causing chronic liver disease all over the world. Sulforaphane (SFN) has been proven to be effective in alleviating many metabolic diseases, such as obesity and type 2 diabetes. In this study, C57BL/6 mice were fed a high-fat diet for 12 weeks to induce MAFLD and given SFN (10 mg per kg bw) daily. Our results showed that SFN not only improved the excessive accumulation of fat in the liver cells but also ameliorated liver and serum inflammatory and antioxidant levels. In addition, SFN can regulate bile-acid metabolism and fatty-acid synthesis by affecting their farnesoid X receptor (FXR)/liver X receptor alpha (LXRα) signaling pathway, ultimately alleviating MAFLD. Our study provides a theoretical basis for the mechanism by which SFN alleviates hepatic steatosis.

Ameliorated effects of a lipopeptide surfactin on insulin resistance in vitro and in vivo.

Surfactin, produced by Bacillus amyloliquefaciens fmb50, was used to treat insulin-resistant (IR) hepatocyte. It was found that surfactin increased glucose consumption in insulin-resistant HepG2 (IR-HepG2) cells and ameliorated IR by increasing glucose transporter 4 (GLUT4) protein expression and AMP-activated protein kinase (AMPK) mRNA expression, promoting GLUT4 translocation and activating phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) in IR-HepG2 cells. Meanwhile, surfactin downregulated protein expression of phosphoenolpyruvate carboxy kinase (PEPCK) and glucose-6-phosphatase (G6Pase), further inhibiting hepatic gluconeogenesis. In addition, surfactin played important roles in eliminating reactive oxygen species (ROS), improving mitochondrial dysfunction, and inhibiting proinflammatory mediators. We observed that surfactin promoted glucose consumption, meanwhile increased translocation and protein expression of GLUT4 in Caco-2 cells. These results confirmed the conclusion in hepatic cells. Furthermore, surfactin supplement decreased body weight, food intake, and fasting blood glucose of type 2 diabetes mellitus (T2DM) mice induced by streptozotocin (STZ)/high-fat diet (HFD). Our data indicated that surfactin ameliorated insulin resistance and lowered blood glucose in intro and in vivo.

Broccoli microgreens have hypoglycemic effect by improving blood lipid and inflammatory factors while modulating gut microbiota in mice with type 2 diabetes.

This study aims to explore the hypoglycemic effect of lyophilized broccoli microgreens on type 2 diabetes (T2D) in mice. The experiment lasted 18 weeks, including 1 week of adaptation (normal diet) and 17-week experimental period (high-fat diet). After ingestion of broccoli microgreens, the body weight and glucose homeostasis were improved. Meanwhile, the blood lipid status, antioxidant indexes, and inflammatory factors level were improved. Moreover, the insulin resistance and the pathological changes in mice organs were reversed. In addition, the composition of gut microbiota and the production of propionic acid in intestinal content were improved. Our experiment proved that broccoli microgreens have the ability to regulate T2D and improve symptoms of mice T2D induced by high-fat diet and streptozotocin (STZ). PRACTICAL APPLICATIONS: For years, the functionality of broccoli microgreens has attracted much attention. This article will prove the therapeutic effect of broccoli microgreens on T2D and explain its principle of action in the management of T2D.

Involvement of AprD in regulating biofilm structure, matrix secretion, and cell metabolism of meat-borne Pseudomonas fragi during chilled storage.

Pseudomonas fragi is by far one of the most threatening species in the spoilage of chilled meat that is stored under aerobic conditions. The membrane protein AprD is a well-established regulator controlling protease secretion in Pseudomonas spp. However, its exact roles in modulating metabolic pathways and spoilage potential of P. fragi at the molecular level remain undefined. Here, an in-frame deletion mutation of aprD was used to explore the impacts on their biofilm structure, matrix secretion, and cell metabolism. The results showed that ΔaprD formed relatively disorganized loose aggregation in biofilm, resulting in a thinner structure and more dead cells. Meanwhile, marked changes in the content of extracellular carbohydrates and proteins were observed. Furthermore, intracellular metabolomic profiling revealed the involvement of aprD in several cellular metabolic pathways, mostly including the carbohydrate pathway, amino acid pathway, and nucleotide pathway, while the characterization of extracellular metabolism clarified the variations in the spoilage-related metabolites (e.g., creatine, IMP, spermine, fatty acids, amino acids, and oligopeptides) could be highly correlated with aprD deletion. In this finding, we indicated that aprD could be responsible for cell reproduction and in situ spoilage potential of P. fragi NMC25 during chilled storage by controlling related metabolism and nutrients utilization. Thus, our results will contribute to an improved understanding of the regulatory mechanism of aprD gene in meat spoilage contaminated with P. fragi, which can be valuable to ensure the quality and safety of meat.

Effect of oxidized dextran on the stability of gallic acid-modified chitosan-sodium caseinate nanoparticles.

We incorporated oxidized dextran (Odex) into nanoparticles composed of gallic acid-modified chitosan (GA-CS) and sodium caseinate (NaCas). The mass ratio of GA-CS to NaCas and the pH of the reaction solution were optimized to obtain nanoparticles with excellent performance and stability. The interactions among various nanomaterials were confirmed by Fourier-transform infrared spectroscopy (FT-IR) and fluorescence spectrometer. The optimized complex nanoparticles had a diameter of approximately 131.2 nm with a polydispersity index (PDI) of 0.14, and a zeta potential of 26.2 mV. Our results showed that Odex enhanced the stability and function of GA-CS/NaCas nanoparticles (NP). At a curcumin loading of 10%, the encapsulation efficiency of Odex-crosslinked GA-CS/NaCas (NP (Odex)) was 96.2%, whereas that for uncrosslinked nanoparticles was 66.9%. Compared to the burst release profile of free curcumin in simulated GI fluids, the sustained release profile of encapsulated curcumin was observed. Radical-scavenging assays confirmed that the nanoparticles had excellent antioxidant activity themselves due to the grafting of phenolic acid on chitosan backbone. Overall, NP (Odex) with good GI stability and antioxidant activity hold promising for the oral delivery of hydrophobic bioactives.