Quantification and health risk assessment of ochratoxin A in dried fruit, spices, and coffee.

Ochratoxin A (OTA) is a stable toxin produced by fungal strains of Aspergillus and Penicillium. It is commonly found in a variety of food products, including dried fruit, coffee, and spices, raising concerns about their safety. This study was aimed to quantify OTA levels in different food products using HPLC with fluorescence detection. The pre-treatment process was optimised by employing immunoaffinity columns with Tween 20 to effectively remove interfering substances. An analytical method was developed, validated, and applied for OTA analysis in dried fruit, spices, and coffee samples. The validation procedure included determining detection and quantification limits, linearity, precision, and accuracy, as per the criteria specified by AOAC International. The validated method was successfully applied for OTA analysis in the selected food samples. Furthermore, health risk assessment was conducted based on the average intake and body weight of the Korean population. From the results, concentrations of OTA in the samples were found to be very low and therefore concluded not to pose significant threats to consumer health.

Effect of Ultraviolet-C Light-Emitting Diode Treatment on Disinfection of Norovirus in Processing Water for Reuse of Brine Water.

Processes in the food industry that use large amounts of water have been an important cause of waterborne disease outbreaks, as they expose individuals to risks for waterborne disease transmission. Developing technologies to ensure the hygiene and safety of food-processing steps is an urgent concern from an economic perspective. Furthermore, economic benefits can be derived if the processed water can be reused under microbiologically safe conditions. Among the major manufacturing processes in the kimchi industry, the brining process for salted kimchi cabbages requires a considerable amount of brine (approximately 2,000-2,500 l/1,000 kg of raw cabbage). The aim of this study was to establish virucidal conditions with ultraviolet-C light-emitting diodes (UVC LEDs) that can ensure the microbiological safety of brine water samples with various turbidities for reuse after disinfection. For quantitative analysis, first of all, magnetic bead separation (MBS) technique was used to capture and recover the human norovirus (HuNoV) virus particles; propidium monoazide (PMA) combined with RT-qPCR (PMA-RT-qPCR) was subsequently used to selectively detect infectious norovirus. Overall, as the turbidity of the brine water samples increased, the reduction in the HuNoV genogroup II genotype 4 (HuNoV GII.4) levels by UVC LED disinfection decreased. The derived inactivation rate constant (kinac ) and inactivation curves (calculated using the log-linear model) were studied as a function of turbidity based on the exponential one-phase inactivation kinetics of HuNoV. Using an impeller system set at 100 rotations/min (rpm) with an eight-nephelometric turbidity unit (NTU) sample (the lowest turbidity studied), the kinact based on the levels of viral genomic RNA concentrations was approximately 2.15-fold higher than that observed without rotation (0 rpm). Moreover, the kinact increased 1.69-fold with a 56-NTU sample (the highest turbidity studied) when the impeller system was set at 100 rpm. UVC LED treatment decreased the HuNoV GII.4 population more effectively in conjunction with the impeller system (100 rpm) than without the impeller system. Our novel findings and model provide fundamental and scientific data that may help reuse brine water and ensure its microbiological safety through disinfection. Our study highlights the benefits of UVC LED treatment in successfully eliminating waterborne viruses in a prompt, resistance-reducing, and energy-efficient approach at the laboratory scale, which lays the foundation for future plant-scale studies of UVC LED-disinfection systems.

Physicochemical stability and virucidal effect of diluted, slightly acidic electrolyzed water against human norovirus.

This study aimed to evaluate the virucidal effect and potential use as a disinfectant of undiluted and diluted slightly acidic electrolyzed water (SAEW) on human noroviruses (HuNoVs) using the in vitro suspension test and in food test. The oxidization reduction potential of SAEW gradually decreased with the increase in distilled water volume. Moreover, as the volume of distilled water and the dilution ratio increased, the available chlorine concentration of the samples significantly decreased from 31.2 ± 0.63 (SAEW) to 1.3 ± 0.21 (1:10 dilution of SAEW solution) (p < 0.05). Undiluted SAEW presented the lowest pH (5.56 ± 0.02) and as SAEW was diluted in distilled water, the pH of the sample increased. Considering the standard reduction values of pathogenic virus (> 4.00 log reduction), the reduction value of HuNoVs in cabbage samples was 4.65 (GI.6) and 4.28 (GII.4) log. These results suggest the potential application of SAEW for inactivating HuNoVs in the food industry. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-01011-w.

Highly Reliable Implementation of Optimized Multicomponent Oxide Systems Enabled by Machine Learning-Based Synthetic Protocol.

Multicomponent oxide systems are one of the essential building blocks in a broad range of electronic devices. However, due to the complex physical correlation between the cation components and their relations with the system, finding an optimal combination for desired physical and/or chemical properties requires an exhaustive experimental procedure. Here, a machine learning (ML)-based synthetic approach is proposed to explore the optimal combination conditions in a ternary cationic compound indium-zinc-tin oxide (IZTO) semiconductor exhibiting high carrier mobility. In particular, by using support vector regression algorithm with radial basis function kernel, highly accurate mobility prediction can be achieved for multicomponent IZTO semiconductor with a sufficiently small number of train datasets (15-20 data points). With a synergetic combination of solution-based synthetic route for IZTO fabrication enabling a facile control of the composition ratio and tailored ML process for multicomponent system, the prediction of high-performance IZTO thin-film transistors is possible with expected field-effect mobility as high as 13.06 cm2 V-1 s-1 at the In:Zn:Sn ratio of 63:27:10. The ML prediction is successfully translated into the empirical analysis with high accuracy, validating the protocol is reliable and a promising approach to accelerate the optimization process for multicomponent oxide systems.

Optimizing Operating Parameters of Electric Ultra-Low Volume Sprayer with Slightly Acidic Electrolyzed Solution for Efficient Virucidal Activity on Environmental Surfaces.

Recently, and considering the COVID-19 pandemic, there has been a growing consensus that the disinfection of surfaces contaminated with pathogenic viral particles is essential. Chemical disinfectant sprays are effective at preventing the spread of infectious human noroviruses (Hu-NoVs) in healthcare and public areas. We assessed the virucidal activity of slightly acidic electrolyzed water (SAEW) spray on fomite surfaces. A multivariate statistical assessment that combined a response surface methodology (RSM) and a Box-Behnken design (BBD) was performed to define the optimal parameters of, and correlations among, experimental conditions. Spraying SAEW disinfectant (oxidation-reduction potential: 1123 mV, pH range: 5.12, available chlorine concentration: 33.22 ppm) resulted in the successful decontamination of Hu-NoV, with a 4-log reduction in viral particles on polyvinyl chloride, stainless steel, ceramic tile, and glass surfaces. Our experimental data revealed optimized treatment conditions for decontaminating Hu-NoV GI.6 and GII.4, using the numerical multiple optimized method (spraying rate: 218 mL/min, spraying time: 4.9 s, spraying distance: 0.9 m). These findings offer significant insights for designing optimal strategic control practices to prevent infectious disease, particularly Hu-NoV, transmission.

Kinetic Modeling of Slightly Acidic Electrolyzed Water Decay Characteristics in Fresh Cabbage Disinfection Against Human Norovirus.

To consistently disinfect fresh vegetables efficiently, the decay of disinfectants such as chlorine, electrolyzed oxidizing water (EOW), ozonated water, and plasma-activated water during the disinfection maintenance stage needs to be understood. The aim of our study was to evaluate the changes in the inactivation kinetics of slightly acidic electrolyzed water (SAEW) against human norovirus (HuNoV), based on the cabbage-to-SAEW ratio. After disinfection of fresh cabbage with disinfected SAEW solution, SAEW samples were collected and analyzed for physicochemical properties such as pH, available chlorine concentrations (ACCs), and oxidation-reduction potential (ORP). SAEW virucidal effects were evaluated. We confirmed the decay of post-disinfection SAEW solution and demonstrated the different patterns of the decay kinetic model for HuNoV GI.6 and GII.4. In addition, the goodness of fit of the tested models based on a lower Akaike information criterion, root-mean-square error (RMSE), and residual sum of squares (RSS) was close to zero. In particular, the change in both the HuNoV GI.6 and GII.4 inactivation exhibited a strong correlation with the changes in the ACC of post-disinfection SAEW. These findings demonstrate that physicochemical parameters of SAEW play a key role in influencing the kinetic behavior of changes in the disinfection efficiency of SAEW during the disinfection process. Therefore, to optimize the efficiency of SAEW, it is necessary to optimize the produce-to-SAEW ratio in future studies.

Antioxidant, Anti-Obesity, and Anti-Aging Activities of Jeju Citrus Blended Vinegar.

Various types of vinegars have been developed as interest in their health benefits has increased. In this study, we prepared Jeju citrus blended vinegars (CBVs) by mixing premature mandarin vinegar and mandarin vinegar, with mandarin vinegar used as a control. The physicochemical properties of the vinegars, including pH, total acidity, and sugar content was determined. Moreover, antioxidant, anti-obesity, and anti-aging activities of the vinegars were investigated. Physicochemical analysis revealed that the CBVs had a pH similar to that of mandarin vinegar, whereas CBVs with relatively high premature mandarin vinegar content showed higher acidity and lower sugar content (p < 0.05). Moreover, the antioxidant activities and phenol contents of CBVs were significantly higher than those of mandarin vinegar (p < 0.05). Meanwhile, CBVs showed significantly decreased intracellular triglyceride, lipid accumulation, and anti-obesity related gene levels (p < 0.05), thereby highlighting their anti-obesity activity. In addition, CBVs showed anti-aging activity by increasing cell viability and cell lifespan, while decreasing the expression of senescence-related genes under H2O2-induced oxidative stress. Therefore, CBVs may be useful as a functional food with antioxidant, anti-obesity, and anti-aging effects in various food fields.

Distinguishing between long-term-stored and fresh chili pepper powder through fingerprinting of volatiles by headspace capillary-gas chromatography-ion mobility spectrometry.

Long-term storage of chili pepper powder results in physicochemical and microbiological changes that decrease its commercial value; these changes occur owing to fungal growth and production of off-flavor compounds. Herein, long-term-stored chili pepper powder (LSCPP) and fresh chili pepper powder (FCPP) were analyzed using internal transcribed spacer sequencing and volatile organic compound fingerprinting by headspace capillary-gas chromatography-ion mobility spectrometry. Fungal analysis detected only Xeromyces bisporus with high accuracy in all the analyzed LSCPP samples. However, the proliferation of X. bisporus on nonspecific spots complicated the distinguishing process between the two groups based solely on fungal analysis. Therefore, nine compounds (three ketones, one alcohol, two aldehydes, one ester, one furan, and one sulfur compound) obtained by autoxidation and fungal metabolism were selected as potential markers for distinguishing LSCPP and FCPP. These above-mentioned substances, which were confirmed as off-flavor species owing to "stale" odor, emitted lipid fragrance and were used to successfully distinguish LSCPP from FCPP using principal component analysis and linear discriminant analysis. PRACTICAL APPLICATION: According to the research results, it was possible to discriminate between long-term stored and fresh chili pepper powders using nine VOC markers for quality control in industry. In addition, the fungus generated from long-term storage of chili pepper powder was Xeromyces bisporus, which was confirmed to be safe for intake because it does not form secondary toxic metabolites.

Voltage program-based MEKC with LIF detection for rapid quantification of native capsaicin and dihydrocapsaicin in foods.

Voltage program (VP)-based micellar electrokinetic chromatography (MEKC) with a laser-induced fluorescence (LIF) detector was developed for fast, high-sensitivity detection of native capsaicin (CAP) and dihydrocapsaicin (DHC) in various foods. The combination of mixed nonionic (Tween 20) and anionic (SDS) surfactants in a sodium borate running buffer showed excellent separation efficiency, selectivity, and speed without loss of resolving power (Rs > 2). Compared to conventional UV absorption, LIF showed enhanced detection sensitivity with detection limits at the pM level. In addition, the developed VP-based MEKC-LIF method was successfully applied for quantification of capsaicin in chili pepper, baechu, and kimchi at a 98% confidence level. CAP and DHC were also analyzed within a short time in extracts from real samples of gochujang, snacks (Swingchip®), black pepper, and ginger but were not detected in garlic.

Influence of Capsaicinoids Content on the Microbial Community during Kimchi Fermentation.

Capsaicinoids in red pepper powder are known to show anti-bacterial effects; however, their effects during kimchi fermentation are not known. This study aimed to investigate the effects of various concentrations of capsaicinoids on kimchi fermentation. Five sets of kimchi samples were prepared using 0 mg/kg (control), 98.34 ± 5.34 mg/kg (mild), 243.47 ± 3.71 mg/kg (medium), 428.63 ± 30.78 mg/kg (hot), and 1,320.49 ± 28.27 mg/kg (extreme) capsaicinoid. The characteristics of each kimchi sample, including pH, acidity, organic acid, sugars, sugar alcohol, capsaicinoid content, and microbial community were periodically investigated during fermentation. Kimchi with red pepper powder shows significantly higher acidity than control kimchi, whereas pH values were the same. Organic acid in kimchi with red pepper powder was higher than in control kimchi, probably caused by higher lactic acid bacteria (LAB) counts in kimchi samples with red pepper powder. Our results show that addition of red pepper powder decreased Leuconostoc spp. counts in the bacterial community. In particular, Lactobacillus sakei and Leuconostoc gelidum counts increased and decreased, respectively, with increasing capsaicinoid content of red pepper powder added to kimchi. Overall, the results of this study indicate that physicochemical properties and LAB such as L. sakei and L. gelidum are influenced by capsaicinoid content. However, further studies are necessary to investigate the effects of the percentage of red pepper powder in kimchi on fermentation to provide practical guidelines for producing standardized kimchi.

Plasmon-Amplified Endogenous Fluorescence Nanospectroscopic Sensor Based on Inherent Elastic Scattering for Ultratrace Ratiometric Detection of Capsaicinoids.

Endogenous fluorescence imaging techniques are key for modern single-molecule quantification without the use of additional labeling probes. However, the drawback of weak fluorescence signal is the primary challenge in meeting the ever-increasing demands of single-molecule detection. Here, we report a simple and reliable method that provides up to ∼100-fold uniform fluorescence enhancement of endogenous fluorescence of the capsaicinoid molecule. The method is based on a single nanoparticle plasmon-amplified endogenous fluorescence nanospectroscopic sensor (PAEFS). This work demonstrated the applicability of PAEFS in refining sensitivity at the single-molecule level by showing ultralow limits of detection (106 times lower than previous reports) of fluorescence-based capsaicinoids with a wide range of linear response (18 zM to 85 pM). Spectrally overlapped capsaicinoid analogues were quantified ratiometrically to detect the analogue percentages in real samples. The novel endogenous fluorescence enhancement approach presented here represents a universal sensor for enhanced detection of single molecules using existing techniques without altering the original molecular features or using add-on labeling probes.

Simultaneous direct determination of 15 glucosinolates in eight Brassica species by UHPLC-Q-Orbitrap-MS.

Glucosinolates (GLS) have been reported to have significant anti-oxidative, antimicrobial, and anti-cancer activities. The current study was aimed to develop an analytical method for glucosinolate quantitation in eight Brassica species from Gwangju, Republic of Korea. For this purpose the UHPLC-Q-Orbitrap-MS technique was used and validated for optimal extraction conditions, detection and quantitation limits, linearity, precision, and accuracy. According to the results of GLS profiling, the total GLS concentration decreased in the order of cabbage > broccoli > cauliflower > mustard > kimchi cabbage > young radish ∼ kale. All Brassica species contained glucoerucin (GER) and glucobrassicin (GBR) as major GLS with the high levels in cabbage (5.913 µM/g) and broccoli (1.723 µM/g), respectively. The contents of minor GLS were species-dependent, and could therefore be used for Brassica species classification.

A scaffold for signaling of Tim-4-mediated efferocytosis is formed by fibronectin.

An essential step during clearance of apoptotic cells is the recognition of phosphatidylserine (PS) exposed on apoptotic cells by its receptors on phagocytes. Tim-4 directly binding to PS and functioning as a tethering receptor for phagocytosis of apoptotic cells has been extensively studied over the past decade. However, the molecular mechanisms by which Tim-4 collaborates with other engulfment receptors during efferocytosis remain elusive. By comparing efferocytosis induced by Tim-4 with that by Anxa5-GPI, an artificial tethering receptor, we found that Tim-4 possesses auxiliary machinery to induce a higher level of efferocytosis than Anxa5-GPI. To search for that, we performed a yeast two-hybrid screen and identified Fibronectin (Fn1) as a novel Tim-4-associating protein. Tim-4 directly associated with Fn1 and formed a complex with integrins via the association of Fn1. Through Tim-4-/- mice and cell-based assays, we found that modulation of the Fn1 level affected efferocytosis induced by Tim-4 and disruption of the interaction between Tim-4 and Fn1 abrogated Tim-4-mediated efferocytosis. In addition, Tim-4 depletion attenuated integrin signaling activation and perturbation of integrin signaling suppressed Tim-4-promoted efferocytosis. Taken together, the data suggest that Fn1 locates Tim-4 and integrins in close proximity by acting as a scaffold, resulting in synergistic cooperation of Tim-4 with integrins for efficient efferocytosis.

Evaluation of ginsenoside bioconversion of lactic acid bacteria isolated from kimchi.

BACKGROUND: Panax ginseng is a physiologically active plant widely used in traditional medicine that is characterized by the presence of ginsenosides. Rb1, a major ginsenoside, is used as the starting material for producing ginsenoside derivatives with enhanced pharmaceutical potentials through chemical, enzymatic, or microbial transformation. METHODS: To investigate the bioconversion of ginsenoside Rb1, we prepared kimchi originated bacterial strains Leuconostoc mensenteroides WiKim19, Pediococcus pentosaceus WiKim20, Lactobacillus brevis WiKim47, Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49 and analyzed bioconversion products using LC-MS/MS mass spectrometer. RESULTS: L. mesenteroides WiKim19 and Pediococcus pentosaceus WiKim20 converted ginsenoside Rb1 into the ginsenoside Rg3 approximately five times more than Lactobacillus brevis WiKim47, Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49. L mesenteroides WIKim19 showed positive correlation with ß-glucosidase activity and higher transformation ability of ginsenoside Rb1 into Rg3 than the other strains whereas, P. pentosaceus WiKim20 showed an elevated production of Rb3 even with lack of ß-glucosidase activity but have the highest acidity among the five lactic acid bacteria (LAB). CONCLUSION: Ginsenoside Rg5 concentration of five LABs have ranged from ∼2.6 µg/mL to 6.5 µg/mL and increased in accordance with the incubation periods. Our results indicate that the enzymatic activity along with acidic condition contribute to the production of minor ginsenoside from lactic acid bacteria.

Identification of 2-hydroxyisocaproic acid production in lactic acid bacteria and evaluation of microbial dynamics during kimchi ripening.

Lactic acid bacteria produce diverse functional metabolites in fermented foods. However, little is known regarding the metabolites and the fermentation process in kimchi. In this study, the culture broth from Leuconostoc lactis, a lactic acid bacterium isolated from kimchi, was analysed by liquid chromatography-tandem mass spectrometry and identified by the MS-DIAL program. The MassBank database was used to analyse the metabolites produced during fermentation. A mass spectrum corresponding to 2-hydroxyisocaproic acid (HICA) was validated based on a collision-induced dissociation (CID) fragmentation pattern with an identified m/z value of 131.07. HICA production by lactic acid bacteria was monitored and showed a positive correlation with hydroxyisocaproate dehydrogenases (HicDs), which play a key role in the production of HICA from leucine and ketoisocaproic acid. Interestingly, the HICA contents of kimchi varied with Leuconostoc and Lactobacillus content during the early stage of fermentation, and the addition of lactic acid bacteria enhanced the HICA content of kimchi. Our results suggest that HICA production in kimchi is dependent on the lactic acid bacterial composition.

Intermolecular steric inhibition of Ephexin4 is relieved by Elmo1.

Ephexin4, a guanine nucleotide-exchange factor for RhoG, promotes engulfment of apoptotic cells and cancer cell migration in a RhoG-dependent manner, which is synergistically augmented by Elmo1, an Ephexin4-interacting protein. However, the underlying molecular mechanism remains elusive. Here, we report a mechanism by which Elmo1 cooperates with Ephexin4 to activate RhoG. We found that Ephexin4 activity was increased by elimination of its SH3 domain which intermolecularly interacts with the N20 region of Ephexin4. This interaction prevented RhoG from binding to Ephexin4 and thus inhibited RhoG activation. Moreover, we also found that Elmo1 associated with the SH3 domain as well as the N20 region and competed with the SH3 domain for binding to the N20 region, interrupting the interaction of the SH3 domain with the N20 region and thereby promoting RhoG binding to Ephexin4. In addition, the activity of Ephexin4 lacking the SH3 domain was comparable to that of Ephexin4 with Elmo1. Taken together, the data suggest that Elmo1 relieves the steric hindrance of Ephexin4 generated by the intermolecular interaction of the SH3 domain and makes Ephexin4 more accessible to RhoG.

A 2D Metal Oxide Nanosheet as an Efficient Additive for Improving Na-Ion Electrode Activity of Graphene-Based Nanocomposites.

An efficient way to improve the Na-ion electrode activity of graphene-based nanocomposite is developed by employing exfoliated metal oxide nanosheet as an additive. The titanate-nanosheet-incorporated Na-SnS2 -reduced graphene oxide (rG-O) nanocomposites can be synthesized by the electrostatically derived restacking of the colloidal mixture of SnS2 , rG-O, and titanate nanosheets with the Na+ cation. The incorporation of titanate into the Na-SnS2 -rG-O nanocomposites is effective in improving the nanoscale mixing of component nanosheets and the porosity of the composite structure. The resulting nanocomposites deliver superior discharge capacities and rate properties to the titanate-free nanocomposite. The universal applicability is further confirmed by MoS2 -rG-O nanocomposites upon the addition of titanate. This study highlights that the exfoliated metal oxide nanosheet can be used as an efficient additive for graphene-based nanocomposites to explore Na-ion electrode materials.

Applicability of a colorimetric method for evaluation of lactic acid bacteria with probiotic properties.

Rapid colorimetric methods using various indicator reagents have been developed to monitor bacterial viability. Here, we examined the applicability of a method based on the reduction of resazurin or water-soluble tetrazolium salt-8 (WST-8) to screen lactic acid bacteria (LAB) for growth, tolerance against bile acid and low pH. The resazurin reduction test proved unsuitable for screening LAB such as Lactobacillus plantarum and Leuconostoc mesenteroides since it reacted with acid present in the cultures. LAB growth could be indirectly quantified by measuring WST-8 reduction. This method proved more sensitive and quickly results than counting bacterial colony forming units and turbidity at 600 nm in the presence of bile and acid. Our results suggested that the WST-8-based method could be useful for the characterization of growth and tolerance of the lactic acid producing bacteria.

Homogeneous cationic substitution for two-dimensional layered metal oxide nanosheets via a galvanic exchange reaction.

The galvanic exchange reaction of an exfoliated 2D layered metal oxide nanosheet (NS) with excess substituent metal cations enables the synthesis of a mixed metal oxide 2D NS with controllable cation compositions and physicochemical properties. The reaction of the exfoliated MnO2 NS with Fe2+ or Sn2+ ions at 90 °C induces the uniform galvanic replacement of Mn ions with these substituent ions, whereas the same reaction at 25 °C results in the intercalative restacking of the negatively-charged MnO2 NS with Fe2+ or Sn2+ cations. Upon the galvanic exchange reaction, the highly anisotropic MnO2 2D NS retains its original 2D morphology and layered structure, which is in stark contrast to 0D nanoparticles yielding hollow nanospheres via the galvanic exchange reaction. This observation is attributable to the thin thickness of the 2D NS allowing the simultaneous replacement of all the component surface-exposed metal ions. The resulting substitution of the MnO2 NS with Fe and Sn ions remarkably improves the electrode performance of the carbon-coated derivatives of the MnO2 NS for lithium ion batteries. The present study clearly demonstrates that the galvanic exchange reaction can provide an efficient method not only to tailor cation compositions but also to improve the functionalities of 2D metal oxide NSs and their carbon-coated derivatives.

Improvement of Na Ion Electrode Activity of Metal Oxide via Composite Formation with Metal Sulfide.

The composite formation with a conductive metal sulfide domain can provide an effective methodology to improve the Na-ion electrode functionality of metal oxide. The heat treatment of TiO2(B) under CS2 flow yields an intimately coupled TiO2(B)-TiS2 nanocomposite with intervened TiS2 domain, since the reaction between metal oxide and CS2 leads to the formation of metal sulfide and CO2. The negligible change in lattice parameters and significant enhancement of visible light absorption upon the reaction with CS2 underscore the formation of conductive metal sulfide domains. The resulting TiO2(B)-TiS2 nanocomposites deliver greater discharge capacities with better rate characteristics for electrochemical sodiation-desodiation process than does the pristine TiO2(B). The 23Na magic angle spinning nuclear magnetic resonance analysis clearly demonstrates that the electrode activities of the present nanocomposites rely on the capacitive storage of Na+ ions, and the TiS2 domains in TiO2(B)-TiS2 nanocomposites play a role as mediators for Na+ ions to and from TiO2(B) domains. According to the electrochemical impedance spectroscopy, the reaction with CS2 leads to the significant enhancement of charge transfer kinetics, which is responsible for the accompanying improvement in electrode performance. The present study provides clear evidence for the usefulness in composite formation between the semiconducting metal oxide and metal sulfide in exploring new efficient NIB electrode materials.