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Soybean soluble dietary fiber (SSDF) was extracted from soy sauce residue and soybean meal. The influence of SSDF on the physicochemical stability and digestive characteristics of soybean oil body (SOB) lotion was investigated by taking the absolute value of Zeta potential, average particle size, peroxide value (POV value), thiobarbituric acid value (TBARS value) and fatty acid release rate (FFA) as characteristic parameters. The results showed that certain concentration of SSDF could effectively reduce the Zeta potential, average particle size, POV value, TBARS value of SOB lotion system, and significantly improve the physical and chemical stability of SOB lotion. In addition, in vitro simulated digestion experiments further showed that the introduction of SSDF can significantly reduce the FFA release rate of SOB emulsion, which effectively delayed the digestion process of lipids in the gastrointestinal tract. This study can provide theoretical basis and reference for the high-value utilization of soybean processing by- products such as soy sauce oil residue and soybean meal, which could improve the processing applicability of SOB, and develop new low-fat health foods containing SOB and SSDF.

Electrochemical mass spectrometry is an important technique for studying the mechanism of electrochemical reactions. Mass spectrometry has the advantages of high detection sensitivity, high detection throughput and high specificity, which enables simultaneous acquisition of qualitative and quantitative informations for multiple components, making it highly valuable in the monitoring of electrochemical reaction products and the identification of intermediates. In general, electrolyte is necessary for electrochemical reaction. However, these electrolyte salts are detrimental to mass spectrometry analysis as they not only cause condensation in the mass spectrometry inlet, leading to blockage, but also impede the signal of the target analyte or form adduct ions with target analyte, resulting in a complex mass spectrum and increased analytical challenges. It is of great significance to develop a mass spectrometry method to real-time obtain trace organic components in high concentration buffer salt solutions. Therefore, a novel atmospheric pressure chemical ionization mass spectrometry (APCI-MS) method was developed for online analysis of trace organic components in high concentration buffer salt solutions, and a small volume flow electrolytic cell, stable performance, and simple structure were fabricated for on-line electrochemical reaction, which employed Pt, Pt and Ag/AgCl as working electrode, counter electrode and reference electrode, respectively. After combination of the APCI-MS and flow electrolytic cell, an electrochemical mass spectrometry device and method for on-line analysis of the electrochemical process in high concentration buffer salt solutions were constructed. As a proof of concept application, the device and method were used to on-line and real-time study the electrochemical oxidation process of dopamine in phosphate buffer salt solutions. The experimental results showed that the APCI-MS method can efficiently remove the inorganic salts in solutions on-line by on-line thermal deposition, while the organic components can be ionized by APCI for mass spectrometry detection. The results of dopamine electrochemical oxidation analysis showed that dopamine was not oxidized under the oxidation potential at 0 V, and only the protonated dopamine m/z 154 [M+H]+ was obtained. When the oxidation potential was +0.3 V, in addition to the protonated dopamine, the protonated peak m/z 150 [M+H]+ of dopachrome was generated by losing 4e- from dopamine, and the protonated peak m/z 303 [M+H]+ of the adduct dopachrome and dopamine formed by the intermolecular hydrogen bonding were also obtained. When the oxidation potential increased to +0.6 V, the contents of oxidation products m/z 150 and m/z 303 were further increased. The results demonstrated that this method has great application potential in studying the electrochemical reaction.

Based on the coupling of hydride generation (HG) and microwave plasma torch (MPT), a rapid and sensitive method of hydride generation-microwave plasma torch-mass spectrometry (HG-MPT-MS) for arsenic under atmospheric condition was developed. The mass spectral behavior of arsenic under different ionization conditions was investigated. In both positive and negative ion modes, arsenic displayed characteristic mass spectrum peaks, which was significantly different from electrospray ionization (ESI), inductively coupled plasma (ICP) and other common ionization techniques. HG-MPT-MS enabled ionization of analytes at molecular level, and it formed adduct ions with NO3-, and even dimers of arsenate ions. Due to the combination of hydride generation and microwave plasma torch, the background noise and the signal intensity of analytes were greatly improved. Therefore, this method was suitable for direct mass spectrometry analysis of trace arsenic in complex samples. In addition, the influence of HCl concentration on the signal intensity, and the regulation of arsine generation behavior by microwave power were studied. Compared with ICP, microwave plasma torch showed more obvious advantages on the analysis of arsenic, such as extremely low power and argon consumption, soft ionization and continuous energy regulation. The total ion chromatography (TIC) and the extracted ion chromatography (EIC) of all analytes displayed good signal stability and peak shape. In addition, arsenic concentration and its signal intensity showed a good linear relationship (R2>0.998) in the concentration range of 1-500 μg/L, and the detection limit was 0.02 μg/L. This method was applied to analysis of a reference water standard and two real water samples of lake water and river water. The results showed that the determined value was in agreement with the certified value for the reference standard. Spiked recoveries of the river water and lake water samples ranged from 95.0% to 105.0% with the relative standard deviation (RSD) of 8.0%-11.0%. On the other hand, the commonly used hydride generation-atomic fluorescence spectrometry (HG-AFS） was also compared with MPT and ICP, which was more economic on power and argon consumption, and had even lower detection limit. However, MPT might have more advantages on simultaneous analysis of multi-elements, such as As, Sb, Bi, Se, Te, Hg and so on. This method was expected to provide a useful tool for sensitive analysis of As and other metalloids from complex matrices.

Lead is a toxic heavy metal with widespread industrial using. The pollution of water resources caused by lead emissions has been highly concerned for a long time. Monitoring the concentration of lead in drinking water is of great significance for preventing its deleterious effects on human health. The main methods for determination of lead in water include graphite furnace atomic absorption spectrometry (GFAAS), flame atomic absorption spectrometry (FAAS), atomic fluorescence spectrometry (AFS), inductively coupled plasma mass spectrometry (ICP-MS), anodic stripping voltammetry (ASV), dithizone spectrophotometry and so on. These methods generally need cumbersome pre-treatments of samples and have the disadvantages of time consuming, large amount of reagents, high energy consumption, and high risk of environmental pollution, which are hard to satisfy the increasing requirements of rapid detection. Although the emerging biosensor technology has the advantages of fast reaction speed and low detection limit, it cannot cope with the presence of multiple ions, and its application of practical samples still needs a further exploration. At present, the rapid analysis of metal ions can also be achieved by using organic mass spectrometry. Based on some previous researches, a method of internal extractive electrospray ionization mass spectrometry (iEESI-MS) was developed for rapid determination of lead in drinking water in this study. Firstly, a drop of 50 μL water sample was dropped onto the polytetrafluoroethylene filter membrane and then sent into an oven at 100 ℃ for 15 min until the water completely evaporated. o-Phenanthroline (Phen) solution was selected as a complexing agent to extract lead on the dry filter membrane, and the Phen-Pb complexes were analyzed in real time by mass spectrometer. The results indicated that the concentration of Pb2+ can be detected as low as 1 μg/L. Meanwhile, the calibration curve had a good linear relationship between the intensity of mass spectrum peaks and the concentration of Pb2+ in the range of 1500 μg/L with the correlation coefficient (R2) of 99.4%, and the recovery was 117%. This fully demonstrates that the method has the advantages of fast detection, high sensitivity and good accuracy. Following this example, other metal ions in water can be further analyzed. In addition, when signals of Phen-Pb complexes were obtained, the signals of anions (such as NO2-, Cl-, SO42-) and organic components in the mass spectrum could also be observed synchronously, showing the outstanding advantage of high throughput. In a word, this method has great potential to be used for implementing the simultaneous detection of multiple indicators in water.

Aflatoxin M1 (AFM1), the only toxin with maximum residue levels in milk, has adverse effects on the intestinal barrier, resulting in intestinal inflammatory disease. Lactoferrin (LF), one of the important bioactive proteins in milk, performs multiple biological functions, but knowledge of the protective effects of LF on the compromised intestinal barrier induced by AFM1 has not been investigated. In the present study, results using Balb/C mice and differentiated Caco-2 cells showed that LF intervention decreased AFM1-induced increased intestinal permeability, improved the protein expression of claudin-3, occludin and ZO-1, and repaired the injured intestinal barrier. The transcriptome and proteome were used to clarify the underlying mechanisms. It was found that LF reduced the intestinal barrier dysfunction caused by AFM1 and was associated with intestinal cell survival related pathways, such as cell cycle, apoptosis and MAPK signaling pathway and intestinal integrity related pathways including endocytosis, tight junction, adherens junction and gap junction. The cross-omics analysis suggested that insulin receptor (INSR), cytoplasmic FMR1 interacting protein 2 (CYFIP2), dedicator of cytokinesis 1 (DOCK1) and ribonucleotide reductase regulatory subunit M2 (RRM2) were the potential key regulators as LF repaired the compromised intestinal barrier. These findings indicated that LF may be an alternative treatment for the compromised intestinal barrier induced by AFM1.

To investigate the values of 10-m drag coefficient (CD) in different coastal areas under the influence of tropical cyclones, the present study used the observational data from four towers in different coastal areas of the South China Sea (SCS) during six tropical cyclone (TC) passages, and employed the eddy covariance method and the flux profile method. The analysis of footprint showed that the fluxes at Zhizai Island (ZZI), Sanjiao Island (SJI) and Donghai Island (DHI) were influenced basically by the ocean, and the flux at Shangyang Town (SYT) was influenced mainly by the land. The results showed that the dependence relationships of CD on 10-m wind speed (U10) in four different coastal areas under the influence of TCs were different. CD at ZZI and SJI initially increased and then decreased as U10 increased, similar to the pattern over the ocean. CD at ZZI and SJI represented the values over shallow water with seawater depths of ~7 m and ~2 m, respectively. Moreover, the critical wind speed at which CD peaked gradually decreased as the seawater depth became shallower in the coastal areas. CD at DHI and SYT decreased monotonously as U10 increased, similar to the pattern over the land. CD at DHI represented the value over the transition zone from shallow water to coastal land, and CD at SYT represented the value over the coastal land. Meanwhile, the eddy covariance method and the flux profile method were compared at ZZI and SYT during TC passages. It was found that their CD values obtained by the two methods were close. Finally, the parameterizations of observed u* and CD as a function of U10 over four different coastal areas were given under the influence of high winds. These parameterizations of observed CD may be used in high-resolution numerical models for landfalling TC forecast. [ABSTRACT FROM AUTHOR]