Sulfur-containing Substances Research Articles

Lead acetate-based test strip method for rapid and quantitative detection of residual sulfur dioxide in Chinese herbal medicines.

To prevent the residual sulfur dioxide in Chinese herbal medicines (CHM) caused by sulfur fumigation, which may lead to severe health issues, there is an urgent need for a rapid and quantitative detection technique. Sodium borohydride was used as a reducing agent to convert sulfur dioxide into hydrogen sulfide, which was then detected using lead acetate test strip. An accurate testing apparatus was designed, consisting of reaction bottle cap, reaction bottle, lead acetate test strip, and sulfur dioxide detector. The effect of different reaction variables on detection, including reductant quality, pH of initial media, reaction time, lead acetate concentration, and membrane type was investigated. The optimal conditions were determined by orthogonal experiments. The reaction membrane type and lead acetate concentration on the membrane were optimized to enhance detection accuracy. Standardized gray cards were fabricated and used to calibrate the detector. The detection system demonstrated an exceptional linear correlation (r2 = 0.9992), with a linear detection range of 0-750 mg·kg-1. The colored substances and sulfur-containing substances within the matrix of CHM did not affect the detection results. Therefore, the detection method exhibited superior accuracy and stability. The proposed technique proved to be swift, reliable, and provides a straightforward and convenient approach for the quantitative determination of sulfur dioxide in CHMs. The results of this work may provide insights into the development of test strips for quantitative detection.

Combustion-explosion suppression and environmental protection of typical sulfur-containing hazardous chemicals.

Sulfur, as a crucial chemical raw, poses increased combustion-explosion risks when mixed with other hazardous substances due to its dual nature as both an oxidant and a reducing agent. Additionally, sulfur-induced combustion and explosions can result in environmental pollution. Combustion-explosion suppression technology plays a crucial role in industrial production by effectively preventing hazardous chemical explosion incidents. This research investigates the combustion-explosion suppression of black powder, a common hazardous chemical containing sulfur, by utilizing two solid-based blast suppressants, NH4H2PO4 and NaHCO3. On this basis, examining changes in the oxidation states of sulfur and explaining the mechanisms of combustion-explosion suppression through the examination of combustion-explosion products. Additionally, numerical calculations are employed to analyze the evolution patterns of gaseous and solid-phase products throughout the entire combustion-explosion process. Research indicates that NaHCO3 exhibits a more effective combustion-explosion suppression effect on black powder compared to NH4H2PO4, which attributed to the valence state transformation of sulfur and the reduction of carbon oxidation. Furthermore, with the enhancement of combustion-explosion suppression effect, K2S, which a pollutes the environment, is gradually transform converted into potassium fertilizer K2SO4, which benefits plants. These results offer new insights into the research of combustion-explosion suppression of sulfur-containing substances and environmental protection strategies.

Impacts of thermal sterilization on volatile substances in xiongzhang tofu seasoning packets according to electronic nose and gas chromatography-mass spectrometry

Seasoning packets, which are essential for pre-cooked Xiongzhang tofu dishes, contain odor substances that are crucial for providing food aromas because of their low molecular weights, boiling points, and volatilities. Identifying these volatile substances is crucial; however, the impact of sterilization on these compounds is not well understood. Therefore, we explored the effect of thermal sterilization on the volatile substance content of Xiongzhang tofu seasoning packets. Three different sterilization treatments were investigated using sensory evaluation, electronic noses, and gas chromatography-mass spectrometry (GC-MS) combined with microbial indicators, orthogonal partial least squares discriminant analysis, the odor activity value (OAV), and differential heat maps. Heat sterilization enhanced flavor richness and preference scores, with the microbial content meeting national standards. GC-MS analysis revealed that pasteurized samples had high similarity with non-sterilized samples, whereas high-temperature/high-pressure sterilized samples showed significant differences. OAV analysis revealed dominant fruity, floral, and spicy aromas, with significant differences in the characteristic compounds among samples. The main characteristic differences among the three treatments were attributed to compounds including (methoxymethyl) ethylene oxide, 2,3-butanediol, epoxypropane, methoxyacetone, methyl thioether, and formic acid. High-temperature/high-pressure sterilization may have facilitated the release of sulfur-containing substances. This study enriches our understanding of the impacts of thermal sterilization of the volatile substance content of seasoning packets in pre-cooked dishes.

Stability of sedimentary organic matter: Insights from molecular and redox analyses

Sedimentary organic matter (SOM) affects the stability of the aquatic carbon pool. The degradation process of SOM is complex for its multifaceted composition. The concentration and properties of SOM affect its steady state, yet the transformation processes of SOM in lakes remain unclear. Here we show the molecular and redox perspectives of SOM stability in polluted sediments with high organic matter content and diverse vegetation. We find significant differences in carbon fractions across various sites. The origin of the organic matter, determined using excitation-emission matrix spectra, influences the consistency of organic matter composition and biochemical degradation in lacustrine sediment. We also observe that sulfur-containing substances decrease carbon chain length and reduce organic matter stability. Fourier-transform ion cyclotron resonance mass spectrometry shows that sulfur-containing substances decrease the degree of saturation and cause reduction. In contrast, nitrogen-containing compounds increase the modified aromaticity index and humin content, enhancing organic carbon complexity and stability (p < 0.05). These results complement the characteristics and transformations of SOM. In a broader perspective, this study contributes to laying the foundation for understanding SOM stability in the carbon cycle and its future effects.

Ionic Liquids as Green and Efficient Desulfurization Media Aiming at Clean Fuel.

With increasingly stringent emission limits on sulfur and sulfur-containing substances, the reduction and removal of sulfur compounds from fuels has become an urgent task. Emissions of sulfur-containing compounds pose a significant threat to the environment and human health. Ionic liquids (ILs) have attracted much attention in recent years as green solvents and functional materials, and their unique properties make them useful alternatives to conventional desulfurization organic solvents. This paper reviews the advantages and disadvantages of traditional desulfurization technologies such as hydrodesulfurization, oxidative desulfurization, biological desulfurization, adsorptive desulfurization, extractive desulfurization, etc. It focuses on the synthesis of ionic liquids and their applications in oxidative desulfurization, extractive desulfurization, extractive oxidative desulfurization, and catalytic oxidative desulfurization, and it analyzes the problems of ionic liquids that need to be solved urgently in desulfurization, looking forward to the development of sulfuric compounds as a kind of new and emerging green solvent in the field of desulfurization.

Dissolution patterns of gold on various structural surfaces in thiosulfate solutions: The effect of interface adsorption on thiosulfate oxidation and gold atom dissociation

Passivation caused by the adsorption and decomposition of thiosulfate on gold surfaces significantly influences the leaching rate of gold. The surface structure often determines the reactivity of an interface. Studying the effects of different surfaces on the decomposition of thiosulfate ions and gold dissolution can provide insights into the passivation formation mechanism. In this study, the oxidation of thiosulfate on different surfaces is investigated using linear voltammetry. The oxidation response of thiosulfate was weaker on granular (1 1 1) and (5 4 1) surfaces than on nanoflakes with (1 1 1) surface. Furthermore, the Tafel test results indicate that the potential for gold dissolution is higher on the granular (1 1 1) and (5 4 1) surfaces, leading to a smaller current value of gold dissolution. Raman spectroscopy indicates that the response signals of the polysulfides and polythionate were stronger on the granular (1 1 1) and (5 4 1) surfaces. The chemical bond changes of thiosulfate adsorbed on different surfaces are studied through molecular simulations based on density functional theory. These results indicate that as the saturation of surface gold atoms decreases, their reaction activity increases, and the bonding effect with thiosulfate ions becomes stronger during adsorption. The changes in the SS bonds in thiosulfate reflect the influence of the different surfaces on their stability. On the (1 1 1) surface, the SS bond changes from the initial 2.102 Å to the adsorbed 2.254 Å, while on the (5 4 1) surface, the SS bond changes to 2.274 Å Although the reaction activity of the granular (1 1 1) and (5 4 1) surfaces is high, the energy barrier for dissociating individual gold atoms from them is higher. The adsorption of sulfur-containing substances on the surface, along with the increased energy barrier for gold dissociation are both factor contributing to the greater difficulty of gold dissolution from granular (1 1 1) and (5 4 1) surfaces.

Efficient electrosynthesis of HO2- from air for sulfide control in sewers

Electrochemically in-situ generation of oxygen and caustic soda is promising for sulfide management while suffers from scaling, poor inactivating capacity, hydrogen release and ammonia escape. In this study, the four-compartment electrochemical cell efficiently captured oxygen molecules from the air chamber to produce HO2- without generating toxic by-products. Meanwhile, the catalyst layer surface of PTFE/CB-GDE maintained a relatively balanced gas-liquid micro-environment, enabling the formation of enduring solid-liquid-gas interfaces for efficient HO2- electrosynthesis. A dramatic increase in HO2- generation rate from 453.3 mg L-1 h-1 to 575.4 mg L-1 h-1 was attained by advancement in operation parameters design (flow channels, electrolyte types, flow rates and circulation types). Stability testing resulted in the HO2- generation rate over 15 g L-1 and the current efficiency (CE) exceeding 85%, indicating a robust stable operational capacity. Furthermore, after 120 mg L-1 HO2- treatment, an increase of 11.1% in necrotic and apoptotic cells in the sewer biofilm was observed, higher than that achieved with the addition of NaOH, H2O2 method. The in-situ electrosynthesis strategy for HO2- represents a significance toward the practical implementation of sulfide abatement in sewers, holding the potential to treat various sulfide-containing wastewater.

Study of the impurity composition of silicon tetrachloride by gas chromatography-mass-spectrometry

Silicon tetrachloride is a sought-after substance in the semiconductor and optoelectronics industries. High demands placed on its purity entail the need for detail information about the impurities present. The impurity composition of silicon tetrachloride obtained by different technologies (chlorination of diatomite and charcoal, disproportionation of trichlorosilane and chlorination of isotopically enriched silicon) was studied using the method of chromatography-mass spectrometry. Study of the possibility of using a DB-5MS 30 m × 0.32 mm × 0.25 μm capillary column with methylsiloxane as a stationary liquid phase to separate impurities revealed that most of the identified substances are eluted in the form of separate chromatographic peaks, which simplifies their determination. The exceptions are impurities N2, O2, Ar, as well as CO2, SiF4, and CHClF2, HCl, H2S. They were registered using the characteristic peaks of the mass spectra. To identify impurities, experimental mass spectra were compared to data from the NIST library and those known from the literature. Information on the impurity composition of SiCl4 has been expanded. It contains permanent gases, aliphatic and chlorine-containing hydrocarbons, chlorides of elements, sulfur-containing substances, and organosilicon compounds. A total of 30 compounds are identified, 19 being discovered for the first time. The mass spectrum of C2H6Cl4OSi2, which is absent in the literature, was obtained and described. For the first time, data on the impurity composition of isotopically enriched silicon tetrachloride have been obtained. A comparative analysis of the impurity composition of the samples under study was carried out and the impurities characteristic of each of them were determined. The data obtained in the study can be used in developing the technology for deep purification of silicon tetrachloride and in characterization of SiCl4 by manufacturing enterprises.

Experimental evaluation of the effect of sulfur content on the spontaneous combustion characteristics parameters of coal

The coal spontaneous combustion (CSC) is the main hazard threatening the coal safety production. In this work, the CSC characteristic, CSC tendency and limit parameters with different sulfur were measured and discussed using temperature-programmed experiment. The results show that the cross-point temperature (CPT) decreases first and then increases with the increasing sulfur content. The CSC tendency of coal with sulfur content in the range of 3.28–5.13 % is greater than that with sulfur content of 2.57 % and 7.59 %. When sulfur content is less than 5.13 %, sulfur and its unstable compounds in coal have strong reactivity and can promote oxidation reaction. When sulfur content is greater than 5.13 %, a large number of sulfur-containing substances reduce the contact area of coal oxygen molecules, which inhibits the oxidation reaction of coal. The sulfur content of coal sample has a significant effect on the limit parameters of coal spontaneous combustion.

Separation and quantification of tire and road wear particles in road dust samples: Bonded-sulfur as a novel marker

Tire road wear particles (TRWPs) are a large source of microplastics in the environment, while the quantification of TRWPs is still challenging due to the complex interferences and the uncertainties and inconsistencies among different methods. This study developed a TRWPs quantification method using optimized pretreatments and bonded-sulfur as marker. Road dust samples (n = 48) were collected, pretreatments including density separation, digestion and extraction were optimized to remove interferences of the bonded-sulfur (minerals, sulfur-containing proteins, hydrosoluble/hydrophobic sulfur-containing substances). Presence of TRWPs in the samples was confirmed by microscopy and scanning electron microscopyenergy dispersive spectrometry. Bonded-sulfur in the samples were quantified by inductively coupled plasmamass spectrometry (ICPMS). Additionally, bonded-sulfur in tire wear particles (TWPs) abraded from tires of top 10 best-selling brands were measured to calculate conversion factor (1.1 ×104 μg/g) for the quantification of TRWPs in real samples. TRWPs contents were 5.40 × 104 μg/g11.02 × 104 μg/g and 2.36 × 104 μg/g5.30 × 104 μg/g in samples from heavy and light traffic roads, respectively. The method provided better recoveries (88–107%, n = 18) and repeatability (RSD=2.0–7.9%, n = 3) compared to methods using rubber, benzothiazole and organic zinc as markers. Furthermore, stability of the bonded-sulfur was validated by Raman and ICPMS. Thus, this accurate and stable quantification method could promote research on TRWPs.

Molecular mechanism and experimental study of fuel oil extractive desulfurization technology based on ionic liquid

In recent years, the sulfur-containing substances produced by fossil fuel combustion have caused overwhelming pollution to the ecological environment, and fuel desulfurization research is imperative. In this paper, 16 ionic liquids (ILs), which are environmentally friendly, easily degradable and have good prospects for industrial application, were selected by combining four cations and four anions for fuel desulfurization research. The desulfurization mechanism of ILs was first investigated by molecular mechanism studies, in which quantum chemical simulations were used for preliminary screening based on the selectivity coefficient of infinite dilution activity coefficient. And the experimental study of extraction desulfurization was carried out with dibenzothiophene (DBT) and n-heptane as model oils. The above mechanism study and experiments examined the effects of temperature, initial fuel oil concentration and ILs to fuel oil feed ratio on the extraction efficiency, and the results showed that both [C2COOCH3ImC6H13][N(CN)2] and [C2COOCH3ImC6H13][NTF2] ILs have more prominent extraction properties. Among them, [C2COOCH3ImC6H13][NTF2] exhibits high desulfurization efficiency for a wide range of sulfur concentration in fuel oils at room temperature due to the advantages of simple preparation method and easier industrialization of the [C2COOCH3ImC6H13][NTF2]. The above experimental results are fully consistent with the molecular simulation predictions, indicating that the theoretical study and experimental method proposed in this paper are simple and feasible.

Establishing Transition Metal Phosphides as Effective Sulfur Hosts in Lithium-Sulfur Batteries through the Triple Effect of "Confinement-Adsorption-Catalysis".

Structurally optimized transition metal phosphides are identified as a promising avenue for the commercialization of lithium-sulfur (Li-S) batteries. In this study, a CoP nanoparticle-doped hollow ordered mesoporous carbon sphere (CoP-OMCS) is developed as a S host with a "Confinement-Adsorption-Catalysis" triple effect for Li-S batteries. The Li-S batteries with CoP-OMCS/S cathode demonstrate excellent performance, delivering a discharge capacity of 1148 mAh g-1 at 0.5 C and good cycling stability with a low long-cycle capacity decay rate of 0.059% per cycle. Even at a high current density of 2 C after 200 cycles, a high specific discharge capacity of 524 mAh g-1 is maintained. Moreover, a reversible areal capacity of 6.56 mAh cm-2 is achieved after 100 cycles at 0.2 C, despite a high S loading of 6.8 mg cm-2 . Density functional theory (DFT) calculations show that CoP exhibits enhanced adsorption capacity for sulfur-containing substances. Additionally, the optimized electronic structure of CoP significantly reduces the energy barrier during the conversion of Li2 S4 (L) to Li2 S2 (S). In summary, this work provides a promising approach to optimize transition metal phosphide materials structurally and design cathodes for Li-S batteries.

Synergistic effects of chemical additives and mature compost on reducing H2S emission during kitchen waste composting

Additives could improve composting performance and reduce gaseous emission, but few studies have explored the synergistic of additives on H2S emission and compost maturity. This research aims to make an investigation about the effects of chemical additives and mature compost on H2S emission and compost maturity of kitchen waste composting. The results showed that additives increased the germination index value and H2S emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and H2S emission reduction (85%). Except for the treatment with only chemical additives, the total sulfur content increased during the kitchen waste composting. The proportion of effective sulfur was higher with the addition of chemical additives, compared with other groups. The relative abundance of H2S-formation bacterial (Desulfovibrio) was reduced and the relative abundance of bacterial (Pseudomonas and Paracoccus), which could convert sulfur-containing substances and H2S to sulfate was improved with additives. In the composting process with both chemical additives and mature compost, the relative abundance of Desulfovibrio was lowest, while the relative abundance of Pseudomonas and Paracoccus was highest. Taken together, the chemical additives and mature compost achieved H2S emission reduction by regulating the dynamics of microbial community.

Thermodynamic and environmental assessment of black liquor supercritical water gasification integrated online salt recovery polygeneration system

Conventional black liquor treatment has weaknesses in pollution. Supercritical water gasification (SCWG) technology makes it possible to utilize the energy of black liquor cleanly. In this work, an auto-thermal SCWG black liquor polygeneration system integrated with online salt recovery was proposed. The performance of salt recovery and gasification was evaluated. The results show that the increasing gasification temperature, black liquor concentration, and salt discharge concentration are favorable to hydrogen production and system efficiency. For salt recovery, the sulfur-containing substances in black liquor are all converted into Na2S/NaHS and recovered in this system. Through exergy analysis, the major exergy destructions are caused by the oxidation unit, SCWG unit, and sub-critical heat transfer. Then, the discharge brine heat is utilized to heat oxygen and feed to reduce the exergy destruction of reaction and heat transfer, which improved the energy efficiency from 78.03% to 88.16%, and the exergy efficiency from 60.86% to 64.10%. After adding a discharge salt utilization unit, the system's hydrogen production is 58,438 Nm3/h and the steam supply is 70,455 kW. This work provides theoretical guidance for the design and establishment of a black liquor SCWG industry system.

Novel macromolecular flame retardant derived from sulfonated naphthalene monomer for simultaneous fire safety and high performance of polycarbonate

Macromolecular flame retardants possess unique advantages in endowing compatible polymers with simultaneous high performance and functionalization because they may greatly reduce incompatibility-caused damage to overall properties of polymer substrates. To address the contraction between fire safety and high performance of polycarbonate (PC), a novel sulfonated naphthalene monomer-containing copolymer polycarbonate, that is named NSD, was synthesized by melt copolymerization and used as flame retardant of PC. Thermal analysis confirmed that the initial decomposition temperature of NSD was 387 °C under nitrogen atmosphere and met the processing of PC. Burning tests results indicated that incorporation of 2 wt.% NSD enabled PC to achieve UL-94 V-0 rating and the LOI value increased to 28.0%; the peak heat release (PHRR) and smoke release of the PC/NSD showed a decreasing trend. Moreover, flame-retarded PC with 2 wt.% NSD maintained comparable tensile strength and elongation at break to neat PC. The flame-retardant and anti-dripping mechanisms were also investigated. Sulfur-containing substances and sulfate in the condensed phase concentrated in the residue and thus strengthened the char layer, and the sulfur dioxide in the gas phase diluted the combustible gas, thus leading to excellent fire retardance of PC/NSDs. Reasons for excellent tensile property of PC/NSDs were also studied in detail. This work demonstrates that macromolecular flame retardants NSD may enable PC to achieve simultaneous high performance and flame retardation.

Oxidation treatment of shale gas produced water: Molecular changes in dissolved organic matter composition and toxicity evaluation

Produced water (PW) is the largest waste stream generated by hydraulic fracturing in an unconventional shale gas reservoir. Oxidation processes (OPs) are frequently used as advanced treatment method in highly complicated water matrix treatments. However, the degradation efficiency is the main focus of research, organic compounds and their toxicity have not been properly explored. Here, we obtained the characterization and transformation of dissolved organic matters of PW samples from the first shale gas field of China by two selected OPs using FT-ICR MS. CHO, CHON, CHOS, and CHONS heterocyclic compounds associated with lignins/CRAM-like, aliphatic/proteins, and carbohydrates compounds were the major organic compounds identified. Electrochemical Fe2+/HClO oxidation preferentially removed aromatic structures, unsaturated hydrocarbons, and tannin compounds with a double-bond equivalence (DBE) value below 7 to more saturated compounds. Nevertheless, Fe (VI) degradation manifested in CHOS compounds with low DBE values, especially single bond compounds. Oxygen- and Sulfur-containing substances, primarily O4–11, S1O3-S1O12, N1S1O4, and N2S1O10 classes, were the main recalcitrant components in OPs. The toxicity assessment showed that the free-radical-formed Fe2+/HClO oxidation could cause significant DNA damage. Therefore, the toxicity response byproducts need spcial attention when conducting OPs. Our results led to discussions on designing appropriate treatment strategies and the development of PW discharge or reuse standards.

Контроль якості вбирної оливи для уловлювання бензольних вуглеводнів за показником виходу коксового залишку.

Specific consumption of absorbent oil and its quality indicators are key characteristics of the benzene department, as they reflect the level of operating costs and determine the degree of equipment contamination with sediments. The thickening of coal tar absorbent oil during operation depends on the level of oil loss with crude benzene, the intensity of the oil polymerization and oxidation reaction, the degree of introduction of resinous and solid substances with coke oven gas, the intensity of coke formation under the influence of high temperatures, and the quality of the absorbent. Recently, little attention has been paid to such an integral indicator of absorbent oil quality as coke residue yield ("coking point"). Coking ability is associated with the viscosity, chemical composition and degree of oil purification, and is used mainly for petroleum oils operating at high temperatures. The relationship between the coke number and the physical and chemical properties of the feedstock can be traced by analyzing the dependence on the average boiling point of the tar fractions. An increase in the viscosity and density of the absorbent oil is reflected in an increase in the coke residue yield in a linear fashion, and a decrease in the content of lowboiling oil distillation in favor of high-boiling oil also increases the coke residue yield. The highest degree of correlation is observed in the exponential dependence of the coke number on the content of substances insoluble in toluene in the oil. The coking point of the absorbing oil is an indicator of the intensity of the oil oxidation and polymerization processes, the presence of corrosion and equipment wear products, the addition of tar and sulfurcontaining substances, and the presence of salts. The use of tar to initiate coke formation is an indicative and convenient way to comparatively assess the performance properties of fresh oil. This makes it possible to use the method of determining the yield of coke residue to assess the tendency of fresh oil to form sediments in equipment. Keywords: absorbent oil, coke residue yield, fractional composition, group composition, dependence, correlation degree. Corresponding author: A.L. Bannikov, e-mail: artiksmartik@gmail.com

식이제한이 마우스 신장의 글루타치온 대사과정에 미치는 영향

Various benefits for the maintenance of metabolic homeostasis can be obtained through dietary restriction. Short-term fasting of mice may induce systemic metabolic remodeling, which may have a significant effect on the level of endogenous metabolites. This study was conducted to examine metabolic changes of sulfur-containing substances in the kidneys of fasted mice over 48 h. No change in the concentration of renal methionine was observed over 48 h; however, significant decreases in the concentrations of S-adenosylmethionine and S-adenosylhomocysteine were observed at both 24 and 48 h after fasting. A significant decrease in the concentration of renal cysteine was observed from 24 h, and this was maintained at 48 h. A significant decrease in the concentration of glutathione (GSH) was observed in the kidney at 48 h, whereas increased concentrations of taurine were observed 48 h after fasting. Although significantly increased expression levels of BHMT were observed, markedly decreased expression levels of CβS were observed at 48 h after fasting, indicating activated generation of methionine, but downregulation of cysteine synthesis. The expression level of γ-GCL was not altered by fasting for 48 h; however, a significant increase of cysteine sulfinate decarboxylase mediating the taurine synthesis was observed. Significantly decreased protein expression levels of solute carrier family 7 member 11, which imports extracellular cystine, were observed at 48 h. These results suggest that the renal methionine concentration was maintained during short-term fasting through an increase in the re-methylation of homocysteine. Moreover, a reduction in the concentration of cysteine was the result of an increase in the synthesis of taurine and a decrease in the uptake of extracellular cystine, which may result in a decreased concentration of renal GSH.

Effect of different sulfur-containing compounds on the structure, sensory properties and antioxidant activities of Maillard reaction products obtained from Pleurotus citrinopileatus hydrolysates

To convert this underutilized P. citrinopileatus which is well known for its savory taste into the high value-added food ingredients, the influence of different sulfur-containing compounds, including l-cysteine (Cys), l-methionine (Met) and thiamine (Thi) on the structure, sensory profiles and antioxidant activities of Maillard Reaction products (MRPs) obtained from P. citrinopileatus was evaluated and compared. Sulfur-containing substances significantly enhanced the Maillard reaction progress and antioxidant activities of MRPs. Cys-MRPs showed the strongest fluorescence intensity and the lowest particle size. Partial least squares regression (PLSR) analysis showed that thiols and Maillard peptides formed in Cys-MRPs exhibited meat-like aroma, kokumi and umami taste, while Met-MRPs exhibited caramel-like aroma attributed to the formation of furans. Therefore, the improvement of MRPs obtained from P. citrinopileatus with various sulfur-containing substances could increase their industrial potential as flavor enhancers with higher antioxidant activities.

The Important Elements in the Formation of Odorous Substances in Black Odorous Water

At present, black odorous water is an important issue in waste water management, as it seriously affects the quality of river and lake water. However, how black odorous water forms still remains largely unclear. Under the conditions of artificially simulating black and odorous water bodies, the formation conditions, generation mechanism and forming process of odorous substances-H2S were researched by adding different basic substances, including sulfur-containing substances, inorganic salts, and metal ions. The results showed that there must be sulfur-containing substances to induce a black bloom in 5–9 d, and that the Oxidation-Reduction Potential (ORP) should be less than −200 mv, an optimal condition for forming black odorous water. Cysteine was the primary precursor for the production of H2S. Furthermore, when the inorganic nitrogen salt additions were &gt;10 mg/L, the formation of H2S was inhibited. Finally, metal ions inhibit the degree of odor-causing in water was Cu2+ &gt; Fe2+ &gt; Mn2+. The microbial communities were also monitored during the development of the black odorous and the predominant bacteria were proteobacteria and it showed that the proteobacteria could desulfurize high-valence organic compounds containing sulfur become low-valence simple sulfides.