Maillard reaction(MR)is a non-enzymatic browning reaction commonly seen in food processing,which occurs between reducing sugars and compounds with amino groups.Despite certain advantages based on Maillard reaction pro...Maillard reaction(MR)is a non-enzymatic browning reaction commonly seen in food processing,which occurs between reducing sugars and compounds with amino groups.Despite certain advantages based on Maillard reaction products(MRPs)found in some food for health and storage application have appeared,however,the MR occurring in human physiological environment can produce advanced glycation end products(AGEs)by non-enzymatic modification of macromolecules such as proteins,lipids and nucleic acid,which could change the structure and functional activity of the molecules themselves.In this review,we take AGEs as our main object,on the one hand,discuss physiologic aging,that is,age-dependent covalent cross-linking and modification of proteins such as collagen that occur in eyes and skin containing connective tissue.On the other hand,pathological aging associated with autoimmune and inflammatory diseases,neurodegenerative diseases,diabetes and diabetic nephropathy,cardiovascular diseases and bone degenerative diseases have been mainly proposed.Based on the series of adverse effects of accelerated aging and disease pathologies caused by MRPs,the possible harm caused by some MR can be slowed down or inhibited by artificial drug intervention,dietary pattern and lifestyle control.It also stimulates people's curiosity to continue to explore the potential link between the MR and human aging and health,which should be paid more attention to for the development of life sciences.展开更多
Background:Traditional Chinese medicines are usually processed before they are used for clinical treatment.This is done in a way associated with the Maillard reaction.Methods:Based on the Maillard reaction,this paper ...Background:Traditional Chinese medicines are usually processed before they are used for clinical treatment.This is done in a way associated with the Maillard reaction.Methods:Based on the Maillard reaction,this paper analyzed the degree of processing of rehmannia root(Rehmanniae radix)relative to the dynamic variation rules of Maillard reaction index parameters,including pH,A420,amino acids,and 5-hydroxymethylfurfural.Furthermore,this study introduced thermal analysis techniques and pyrolysis kinetics to assess the influence of the correlation between processing raw rehmannia root and the Maillard reaction during carbonization.It then went through the whole process of transforming the raw material to end-product in order to explain the scientific connotation of processing it.Results:The results showed that each time rehmannia root was processed,its pH value and amino acid content decreased,while the A420 value and 5-HMF increased.Processing with wine shows a significant difference in these experimental indexes.The position and intensity of the maximum thermal weight loss rate peak of processed rehmannia root at different degrees of processing are different.Comprehensive quantitative 221±0.2°C for processed rehmannia root carbonization was the processing temperature limit.Moreover,the kinetic solution verified that the activation energy corresponding to the carbonization temperature was close to the maximum value of the activation energy of the whole carbonization process,and the optimal mechanism function was g(α)=((1−α)−1/3−1)2.Conclusion:The Maillard reaction occurred during the processing of rehmannia root mixed with carbonization.With each increase of the number of steaming and drying cycles involved in the processing,the level of Maillard reaction increased significantly.The wine-steaming method had a significant effect on the quality of the processed product.展开更多
Tea as the most consumed beverage in the world has received enormous attention for its promoting health benefits.The deleterious effect ofα-dicarbonyls and AGEs formed in Maillard reaction is also a longterm challeng...Tea as the most consumed beverage in the world has received enormous attention for its promoting health benefits.The deleterious effect ofα-dicarbonyls and AGEs formed in Maillard reaction is also a longterm challenge.The connection between the two topics was the main aim of this review,to address and update the antiglycation effect and mechanism of tea and tea polyphenols.By analyzing recent publications,we have covered across chemistry models,cell lines and animal studies.Tea polyphenols,particularly catechins,showed outstanding antiglycation effect by trappingα-dicarbonyl compounds and impeding AGEs formation.Reduction of carbonyl stress brought alleviation to aging,diabetes,and collagen related diseases or complications through regulation of RAGE expression and subsequent MAPK and TGF-βpathway.Therefore,tea polyphenols can serve as promising natural candidates in the treatment and/or prevention of nephropathy,retinopathy,hepatopathy,hyperglycemia and obesity among others,by their potent antiglycation effect.Further studies need to address on aspects like exact mechanisms,solution of detection obstacles,balance of practical usage and harmful effects such as potential flavor damage and toxicity in food,to gain a comprehensive understanding of antiglycation activities of tea polyphenols and its actual application.展开更多
The stewed pork balls with brown sauce(SPB-BS)in China is well known for its delicacy and preferred by consumers.Maillard reaction(MR)is widespread in SPB-BS due to the use of sugar,meat and sauce in the thermal proce...The stewed pork balls with brown sauce(SPB-BS)in China is well known for its delicacy and preferred by consumers.Maillard reaction(MR)is widespread in SPB-BS due to the use of sugar,meat and sauce in the thermal process.However,there is a lack of research on its risk and flavor by MR.By solid phase extraction combined with HPLC-MS,4 kinds of harmful compounds including acrylamide(AA),heterocyclic aromatic amines(HAAs),4-methylimidazole(4-MEI)and furan were analyzed in SPB-BS and their amounts ranged 0.05–0.50 mg/kg.The quantitative formula was proposed to evaluate the risk value of the SPB-BS,after taking into account the content,acceptable daily intake(ADI)and carcinogenicity of each compound.The risk values were in range of 0.57–37.93,suggesting that the risk caused by MR in SPB-BS was low.By head space-solid phase microextraction combined with GC-MS,57 volatile compounds in SPB-BS were identified with the dominant contribution of alcohols,aldehydes,acids and esters.Based on the structures of these compounds and the composition of SPB-BS,lipid oxidation and MR are inferred to be responsible for the formation of the harmful and volatile compounds.In addition,the added sauces and oil provides the main precursors to form the harmful and volatile compounds in SPB-BS,so it is necessary to point out a balance between them in the further study.展开更多
The objective of this work was to investigate the effects of oxidation and Maillard reaction on free and protein-bound N^ε-carboxymethyllysine(CML)and Nε-carboxyethyllysine(CEL)formation during braised chicken proce...The objective of this work was to investigate the effects of oxidation and Maillard reaction on free and protein-bound N^ε-carboxymethyllysine(CML)and Nε-carboxyethyllysine(CEL)formation during braised chicken processing.It was found that a positive correlation was observed between carbonyl,fat oxidation,Maillard reaction,CML and CEL(P<0.05).The sulfhydryl groups could be used as potential indicators to evaluate the compounds’interaction levels between Maillard reaction and protein oxidation.Frying promoted the formation of lysine(Lys),glyoxal(GO)and methylglyoxal(MGO)(P<0.05);boiling enhanced the formation of GO and MGO(P<0.05)while inhibited the levels of Lys(P<0.05);sterilizing blocked the formation of MGO and Lys(P<0.01)but improved GO levels(P<0.05).Finally,a perspective was concluded that the Maillard reaction combined with oxidation is one of the main reasons for the formation of free and protein-bound CML and CEL during braised chicken processing.展开更多
The recombinant DNA technology enabled the production of a variety of human therapeutic proteins.Accumulated clinical experience,however,indicates that the formation of antibodies against such proteins is a general ph...The recombinant DNA technology enabled the production of a variety of human therapeutic proteins.Accumulated clinical experience,however,indicates that the formation of antibodies against such proteins is a general phenomenon rather than an exception.The immunogenicity of therapeutic proteins results in inefficient therapy and in the development of undesired,sometimes life-threatening,side reactions.The human proteins,designed for clinical application,usually have the same amino acid sequence as their native prototypes and it is not yet fully clear what the reasons for their immunogenicity are.In previous studies we have demonstrated for the first time that interferon-b(IFN-b)pharmaceuticals,used for treatment of patients with multiple sclerosis,do contain advanced glycation end products(AGEs)that contribute to IFN-b immunogenicity.AGEs are the final products of a chemical reaction known as the Maillard reaction or glycation,which implication in protein drugs' immunogenicity has been overlooked so far.Therefore,the aim of the present article is to provide a comprehensive overview on the Maillard reaction with emphasis on experimental data and theoretical consideration telling us why the Maillard reaction warrants special attention in the context of the welldocumented protein drugs' immunogenicity.展开更多
Isovaleraldehyde possesses malty,fruity,cocoa-like odor and is widely used in fruit,chocolate,coffee flavors.The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper.The eff...Isovaleraldehyde possesses malty,fruity,cocoa-like odor and is widely used in fruit,chocolate,coffee flavors.The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper.The effects of the ratio of D-glucose/L-leucine, reaction temperature and pH value on the yield of isovaleraldehyde were explored.The optimum conditions were as follows: n(D-glucose):n(L-leucine)=4,temperature 150℃,reaction time 3 h,pH 5.The highest yield of isovaleraldehyde obtained was about 32%.展开更多
Maillard Reaction Products (MRP) was prepared from glucose and glysine heated at 90°C in air circulating oven for 12 hours. The effect of MRP on chlorophyll stability in green peas was investigated. The addition ...Maillard Reaction Products (MRP) was prepared from glucose and glysine heated at 90°C in air circulating oven for 12 hours. The effect of MRP on chlorophyll stability in green peas was investigated. The addition of Maillard Reaction Products (MRP) decreased the loss of chlorophyll a, chlorophyll b and total chlorophyll. The conversion of pheophytin and pyropheophytin were also reduced by the addition of MRP.展开更多
Cra a 4 is a heat stable allergen in oyster,the effect of Maillard reaction on the immunoreactivity and structure of Cra a 4 was investigated.Firstly,Cra a 4 was cloned,expressed and identified.The purified Cra a 4 wa...Cra a 4 is a heat stable allergen in oyster,the effect of Maillard reaction on the immunoreactivity and structure of Cra a 4 was investigated.Firstly,Cra a 4 was cloned,expressed and identified.The purified Cra a 4 was incubated with xylose at 100℃,pH 8.5 for 30 min or with glucose for 60 min.After Maillard reaction,the IgE-binding activity of Cra a 4 and in vitro digested samples was reduced by about 50%.The unfoldα-helix and higher surface hydrophobicity of glycated Cra a 4 were identified as the reason for hypo-immunoreactivity.The higher frequency of lysine(13%)in the primary structure and exposure on the surface of the spatial structure was attributed to the hypo-immunoreactivity of Cra a 4 after Maillard reaction.It comprehensively evaluated the effects of Maillard reaction on Cra a 4 and provids new methods for the industrial production of hypoallergenic oyster.The modified Cra a 4 by Maillard reaction could be a hypoallergenic therapeutic agent for allergy to oyster.展开更多
The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and ...The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and analyzed by gas chromatography-ion mobility spectroscopy(GC-IMS).The characteristic flavor fingerprints of Maillard reaction products(MRPs)of L.edodes enzymatic hydrolysate were constructed.The differences in the characteristic flavors of Maillard reaction with different reducing sugars and VC were compared.The main characteristic flavor,characteristic peak,characteristic marker substance and content were determined,a principal component analysis(PCA)of volatile organic compounds(VOCs)was carried out.The results showed that there were 42 kinds of monomers and some dimers of volatile compounds in the samples including 17 aldehydes,5 alcohols,7 ketones,2 esters,2 acids,7 other compounds and 2 ethers.The volatile VOCs of the sample with added sucrose,VC and L-arabinose were significantly higher than those of the enzymatic hydrolysate of L.edodes.After the Maillard reaction,the flavor of the hydrolysate was significantly improved,and the main components changed significantly.展开更多
The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct ...The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.展开更多
The shock-induced reaction mechanism and characteristics of Ni/Al system,considering an Al nanoparticle-embedded Ni single crystal,are investigated through molecular dynamics simulation.For the shock melting of Al nan...The shock-induced reaction mechanism and characteristics of Ni/Al system,considering an Al nanoparticle-embedded Ni single crystal,are investigated through molecular dynamics simulation.For the shock melting of Al nanoparticle,interfacial crystallization and dissolution are the main characteristics.The reaction degree of Al particle first increases linearly and then logarithmically with time driven by rapid mechanical mixing and following dissolution.The reaction rate increases with the decrease of particle diameter,however,the reaction is seriously hindered by interfacial crystallization when the diameter is lower than 9 nm in our simulations.Meanwhile,we found a negative exponential growth in the fraction of crystallized Al atoms,and the crystallinity of B2-NiAl(up to 20%)is positively correlated with the specific surface area of Al particle.This can be attributed to the formation mechanism of B2-NiAl by structural evolution of finite mixing layer near the collapsed interface.For shock melting of both Al particle and Ni matrix,the liquid-liquid phase inter-diffusion is the main reaction mechanism that can be enhanced by the formation of internal jet.In addition,the enhanced diffusion is manifested in the logarithmic growth law of mean square displacement,which results in an almost constant reaction rate similar to the mechanical mixing process.展开更多
High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion te...High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for efficient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm^(-2)at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excellent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved electrocatalytic reaction mechanism for the in-situ generated nickel–iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced catalytic activity and durability.These findings provide promising strategies for the rational design of nonnoble metal OER catalysts.展开更多
Extensive experimental studies have been performed on the Diels-Alder(DA)reactions in ionic liquids(ILs),which demonstrate that the IL environment can significantly influence the reaction rates and selectivity.However...Extensive experimental studies have been performed on the Diels-Alder(DA)reactions in ionic liquids(ILs),which demonstrate that the IL environment can significantly influence the reaction rates and selectivity.However,the underlying microscopic mechanism remains ambiguous.In this work,the multiscale reaction density functional theory is applied to explore the effect of 1-butyl-3-methylimidazolium hexafluorophosphate([BMIM][PF_(6)])solvent on the reaction of cyclopentadiene(CP)with acrolein,methyl acrylate,or acrylonitrile.By analyzing the free energy landscape during the reaction,it is found that the polarization effect has a relatively small influence,while the solvation effect makes both the activation free energy and reaction free energy decrease.In addition,the rearrangement of local solvent structure shows that the cation spatial distribution responds more evidently to the reaction than the anion,and this indicates that the cation plays a dominant role in the solvation effect and so as to affect the reaction rates and selectivity of the DA reactions.展开更多
Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely use...Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic insights.In this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the HER.In addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during HER.These spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.展开更多
Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membr...Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.展开更多
基金financially supported by grants from the National Natural Science Foundation of China (82170873,81871095)the National Natural Science Foundation of China (81974503)the Tsinghua University Spring Breeze Fund (20211080005)。
文摘Maillard reaction(MR)is a non-enzymatic browning reaction commonly seen in food processing,which occurs between reducing sugars and compounds with amino groups.Despite certain advantages based on Maillard reaction products(MRPs)found in some food for health and storage application have appeared,however,the MR occurring in human physiological environment can produce advanced glycation end products(AGEs)by non-enzymatic modification of macromolecules such as proteins,lipids and nucleic acid,which could change the structure and functional activity of the molecules themselves.In this review,we take AGEs as our main object,on the one hand,discuss physiologic aging,that is,age-dependent covalent cross-linking and modification of proteins such as collagen that occur in eyes and skin containing connective tissue.On the other hand,pathological aging associated with autoimmune and inflammatory diseases,neurodegenerative diseases,diabetes and diabetic nephropathy,cardiovascular diseases and bone degenerative diseases have been mainly proposed.Based on the series of adverse effects of accelerated aging and disease pathologies caused by MRPs,the possible harm caused by some MR can be slowed down or inhibited by artificial drug intervention,dietary pattern and lifestyle control.It also stimulates people's curiosity to continue to explore the potential link between the MR and human aging and health,which should be paid more attention to for the development of life sciences.
基金This research was funded by General Project of the National Natural Science Foundation of China(No.81673601)the Key Research&Development Plan of Shanxi Province(Social Development Project,No.201603D3112002)Cultivate Scientific Research Excellence Programs of Higher Education Institutions in Shanxi(No.2019KJ032).
文摘Background:Traditional Chinese medicines are usually processed before they are used for clinical treatment.This is done in a way associated with the Maillard reaction.Methods:Based on the Maillard reaction,this paper analyzed the degree of processing of rehmannia root(Rehmanniae radix)relative to the dynamic variation rules of Maillard reaction index parameters,including pH,A420,amino acids,and 5-hydroxymethylfurfural.Furthermore,this study introduced thermal analysis techniques and pyrolysis kinetics to assess the influence of the correlation between processing raw rehmannia root and the Maillard reaction during carbonization.It then went through the whole process of transforming the raw material to end-product in order to explain the scientific connotation of processing it.Results:The results showed that each time rehmannia root was processed,its pH value and amino acid content decreased,while the A420 value and 5-HMF increased.Processing with wine shows a significant difference in these experimental indexes.The position and intensity of the maximum thermal weight loss rate peak of processed rehmannia root at different degrees of processing are different.Comprehensive quantitative 221±0.2°C for processed rehmannia root carbonization was the processing temperature limit.Moreover,the kinetic solution verified that the activation energy corresponding to the carbonization temperature was close to the maximum value of the activation energy of the whole carbonization process,and the optimal mechanism function was g(α)=((1−α)−1/3−1)2.Conclusion:The Maillard reaction occurred during the processing of rehmannia root mixed with carbonization.With each increase of the number of steaming and drying cycles involved in the processing,the level of Maillard reaction increased significantly.The wine-steaming method had a significant effect on the quality of the processed product.
基金funded by Hubei Science and Technology Plan Key Project(G2019ABA100)。
文摘Tea as the most consumed beverage in the world has received enormous attention for its promoting health benefits.The deleterious effect ofα-dicarbonyls and AGEs formed in Maillard reaction is also a longterm challenge.The connection between the two topics was the main aim of this review,to address and update the antiglycation effect and mechanism of tea and tea polyphenols.By analyzing recent publications,we have covered across chemistry models,cell lines and animal studies.Tea polyphenols,particularly catechins,showed outstanding antiglycation effect by trappingα-dicarbonyl compounds and impeding AGEs formation.Reduction of carbonyl stress brought alleviation to aging,diabetes,and collagen related diseases or complications through regulation of RAGE expression and subsequent MAPK and TGF-βpathway.Therefore,tea polyphenols can serve as promising natural candidates in the treatment and/or prevention of nephropathy,retinopathy,hepatopathy,hyperglycemia and obesity among others,by their potent antiglycation effect.Further studies need to address on aspects like exact mechanisms,solution of detection obstacles,balance of practical usage and harmful effects such as potential flavor damage and toxicity in food,to gain a comprehensive understanding of antiglycation activities of tea polyphenols and its actual application.
基金the National Science Foundation of China(Grant No.31771931)the start-up funds for scientific research at North University of China(304-1101285714)+1 种基金the Science and Technology Planning Project of Guangdong Province of China(No.2014B020205001 and No.2013B051000015)the 111 Project(B17018).
文摘The stewed pork balls with brown sauce(SPB-BS)in China is well known for its delicacy and preferred by consumers.Maillard reaction(MR)is widespread in SPB-BS due to the use of sugar,meat and sauce in the thermal process.However,there is a lack of research on its risk and flavor by MR.By solid phase extraction combined with HPLC-MS,4 kinds of harmful compounds including acrylamide(AA),heterocyclic aromatic amines(HAAs),4-methylimidazole(4-MEI)and furan were analyzed in SPB-BS and their amounts ranged 0.05–0.50 mg/kg.The quantitative formula was proposed to evaluate the risk value of the SPB-BS,after taking into account the content,acceptable daily intake(ADI)and carcinogenicity of each compound.The risk values were in range of 0.57–37.93,suggesting that the risk caused by MR in SPB-BS was low.By head space-solid phase microextraction combined with GC-MS,57 volatile compounds in SPB-BS were identified with the dominant contribution of alcohols,aldehydes,acids and esters.Based on the structures of these compounds and the composition of SPB-BS,lipid oxidation and MR are inferred to be responsible for the formation of the harmful and volatile compounds.In addition,the added sauces and oil provides the main precursors to form the harmful and volatile compounds in SPB-BS,so it is necessary to point out a balance between them in the further study.
基金This work was supported by China Agriculture Research System(CARS-41-Z06)National Key R&D Program(2016YFD040040303)+1 种基金Key R&D Program(Modern Agriculture)of Jiangsu Province(BE2019308)Nanjing Customs Scientific Research Project(No.2020KJ24).
文摘The objective of this work was to investigate the effects of oxidation and Maillard reaction on free and protein-bound N^ε-carboxymethyllysine(CML)and Nε-carboxyethyllysine(CEL)formation during braised chicken processing.It was found that a positive correlation was observed between carbonyl,fat oxidation,Maillard reaction,CML and CEL(P<0.05).The sulfhydryl groups could be used as potential indicators to evaluate the compounds’interaction levels between Maillard reaction and protein oxidation.Frying promoted the formation of lysine(Lys),glyoxal(GO)and methylglyoxal(MGO)(P<0.05);boiling enhanced the formation of GO and MGO(P<0.05)while inhibited the levels of Lys(P<0.05);sterilizing blocked the formation of MGO and Lys(P<0.01)but improved GO levels(P<0.05).Finally,a perspective was concluded that the Maillard reaction combined with oxidation is one of the main reasons for the formation of free and protein-bound CML and CEL during braised chicken processing.
文摘The recombinant DNA technology enabled the production of a variety of human therapeutic proteins.Accumulated clinical experience,however,indicates that the formation of antibodies against such proteins is a general phenomenon rather than an exception.The immunogenicity of therapeutic proteins results in inefficient therapy and in the development of undesired,sometimes life-threatening,side reactions.The human proteins,designed for clinical application,usually have the same amino acid sequence as their native prototypes and it is not yet fully clear what the reasons for their immunogenicity are.In previous studies we have demonstrated for the first time that interferon-b(IFN-b)pharmaceuticals,used for treatment of patients with multiple sclerosis,do contain advanced glycation end products(AGEs)that contribute to IFN-b immunogenicity.AGEs are the final products of a chemical reaction known as the Maillard reaction or glycation,which implication in protein drugs' immunogenicity has been overlooked so far.Therefore,the aim of the present article is to provide a comprehensive overview on the Maillard reaction with emphasis on experimental data and theoretical consideration telling us why the Maillard reaction warrants special attention in the context of the welldocumented protein drugs' immunogenicity.
文摘Isovaleraldehyde possesses malty,fruity,cocoa-like odor and is widely used in fruit,chocolate,coffee flavors.The preparation of natural isovaleraldehyde by the Maillard model reaction was studied in this paper.The effects of the ratio of D-glucose/L-leucine, reaction temperature and pH value on the yield of isovaleraldehyde were explored.The optimum conditions were as follows: n(D-glucose):n(L-leucine)=4,temperature 150℃,reaction time 3 h,pH 5.The highest yield of isovaleraldehyde obtained was about 32%.
文摘Maillard Reaction Products (MRP) was prepared from glucose and glysine heated at 90°C in air circulating oven for 12 hours. The effect of MRP on chlorophyll stability in green peas was investigated. The addition of Maillard Reaction Products (MRP) decreased the loss of chlorophyll a, chlorophyll b and total chlorophyll. The conversion of pheophytin and pyropheophytin were also reduced by the addition of MRP.
基金supported by a grant from Xiamen Ocean Vocational College (KYG202108)a grant from the young and middle-aged teachers’education research project of Fujian Province (JAT210801,JAT210803)+3 种基金the National Natural Scientific Foundation of China (32072336,31871720,32001695,31901811)the science and technology program of Fujian Province (2021L3013)the science and technology program of Xiamen City (3502Z20203059)grants from the National Key R&D Program of China (2019YFD0901703).
文摘Cra a 4 is a heat stable allergen in oyster,the effect of Maillard reaction on the immunoreactivity and structure of Cra a 4 was investigated.Firstly,Cra a 4 was cloned,expressed and identified.The purified Cra a 4 was incubated with xylose at 100℃,pH 8.5 for 30 min or with glucose for 60 min.After Maillard reaction,the IgE-binding activity of Cra a 4 and in vitro digested samples was reduced by about 50%.The unfoldα-helix and higher surface hydrophobicity of glycated Cra a 4 were identified as the reason for hypo-immunoreactivity.The higher frequency of lysine(13%)in the primary structure and exposure on the surface of the spatial structure was attributed to the hypo-immunoreactivity of Cra a 4 after Maillard reaction.It comprehensively evaluated the effects of Maillard reaction on Cra a 4 and provids new methods for the industrial production of hypoallergenic oyster.The modified Cra a 4 by Maillard reaction could be a hypoallergenic therapeutic agent for allergy to oyster.
基金This work was supported by the Innovative Engineering project of Shandong Academy of Agricultural Sciences(CXGC2022A36)Modern Agricultural Industry Technology System of Shandong Province(SDAIT-07-09).
文摘The characteristic flavor of the enzymatic hydrolysate of Lentinus edodes,which was involved in the Maillard reaction by xylose,fructose,glucose,sucrose,mannose,maltose,vitamin C(VC)and L-arabinose,was determined and analyzed by gas chromatography-ion mobility spectroscopy(GC-IMS).The characteristic flavor fingerprints of Maillard reaction products(MRPs)of L.edodes enzymatic hydrolysate were constructed.The differences in the characteristic flavors of Maillard reaction with different reducing sugars and VC were compared.The main characteristic flavor,characteristic peak,characteristic marker substance and content were determined,a principal component analysis(PCA)of volatile organic compounds(VOCs)was carried out.The results showed that there were 42 kinds of monomers and some dimers of volatile compounds in the samples including 17 aldehydes,5 alcohols,7 ketones,2 esters,2 acids,7 other compounds and 2 ethers.The volatile VOCs of the sample with added sucrose,VC and L-arabinose were significantly higher than those of the enzymatic hydrolysate of L.edodes.After the Maillard reaction,the flavor of the hydrolysate was significantly improved,and the main components changed significantly.
基金supported by the Taishan Scholar Program of Shandong Province,China (tsqn202211162)the National Natural Science Foundation of China (22102079)the Natural Science Foundation of Shandong Province of China (ZR2021YQ10,ZR2022QB163)。
文摘The poor stability of RuO_(2)electrocatalysts has been the primary obstacles for their practical application in polymer electrolyte membrane electrolyzers.To dramatically enhance the durability of RuO_(2)to construct activity-stability trade-off model is full of significance but challenging.Herein,a single atom Zn stabilized RuO_(2)with enriched oxygen vacancies(SA Zn-RuO_(2))is developed as a promising alternative to iridium oxide for acidic oxygen evolution reaction(OER).Compared with commercial RuO_(2),the enhanced Ru–O bond strength of SA Zn-RuO_(2)by forming Zn-O-Ru local structure motif is favorable to stabilize surface Ru,while the electrons transferred from Zn single atoms to adjacent Ru atoms protects the Ru active sites from overoxidation.Simultaneously,the optimized surrounding electronic structure of Ru sites in SA ZnRuO_(2)decreases the adsorption energies of OER intermediates to reduce the reaction barrier.As a result,the representative SA Zn-RuO_(2)exhibits a low overpotential of 210 mV to achieve 10 mA cm^(-2)and a greatly enhanced durability than commercial RuO_(2).This work provides a promising dual-engineering strategy by coupling single atom doping and vacancy for the tradeoff of high activity and catalytic stability toward acidic OER.
基金supported by the State Key Program of National Natural Science Foundation of China(Grant No.12132003)State Key Laboratory of Explosion Science and Technology(Grant No.QNKT20-07)。
文摘The shock-induced reaction mechanism and characteristics of Ni/Al system,considering an Al nanoparticle-embedded Ni single crystal,are investigated through molecular dynamics simulation.For the shock melting of Al nanoparticle,interfacial crystallization and dissolution are the main characteristics.The reaction degree of Al particle first increases linearly and then logarithmically with time driven by rapid mechanical mixing and following dissolution.The reaction rate increases with the decrease of particle diameter,however,the reaction is seriously hindered by interfacial crystallization when the diameter is lower than 9 nm in our simulations.Meanwhile,we found a negative exponential growth in the fraction of crystallized Al atoms,and the crystallinity of B2-NiAl(up to 20%)is positively correlated with the specific surface area of Al particle.This can be attributed to the formation mechanism of B2-NiAl by structural evolution of finite mixing layer near the collapsed interface.For shock melting of both Al particle and Ni matrix,the liquid-liquid phase inter-diffusion is the main reaction mechanism that can be enhanced by the formation of internal jet.In addition,the enhanced diffusion is manifested in the logarithmic growth law of mean square displacement,which results in an almost constant reaction rate similar to the mechanical mixing process.
基金the staff at Beamline (BL08U1-A and BL11B)of the Shanghai Synchrotron Radiation Facility (SSRF)the support from the National Key Research&Development Program of China (2022YFB3803700)+2 种基金the National Natural Science Foundation of China (52171186)the support through the Overseas Outstanding Youth Fund and Shanghai Pujiang Talent Project (21PJ1408500)the financial support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘High efficiency,cost-effective and durable electrocatalysts are of pivotal importance in energy conversion and storage systems.The electro-oxidation of water to oxygen plays a crucial role in such energy conversion technologies.Herein,we report a robust method for the synthesis of a bimetallic alkoxide for efficient oxygen evolution reaction(OER)for alkaline electrolysis,which yields current density of 10 mA cm^(-2)at an overpotential of 215 mV in 0.1 M KOH electrolyte.The catalyst demonstrates an excellent durability for more than 540 h operation with negligible degradation in activity.Raman spectra revealed that the catalyst underwent structure reconstruction during OER,evolving into oxyhydroxide,which was the active site proceeding OER in alkaline electrolyte.In-situ synchrotron X-ray absorption experiment combined with density functional theory calculation suggests a lattice oxygen involved electrocatalytic reaction mechanism for the in-situ generated nickel–iron bimetal-oxyhydroxide catalyst.This mechanism together with the synergy between nickel and iron are responsible for the enhanced catalytic activity and durability.These findings provide promising strategies for the rational design of nonnoble metal OER catalysts.
基金supported by the National Natural Science Foundation of China(22168002,22108070,21878078)the Natural Science Foundation of Guangxi Province(2020GXNSFAA159119)+2 种基金the Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021Z012)the Open Fund of the State Key Laboratory of Molecular Reaction Dynamics in DICP(SKLMRD-K202106)the Young Elite Scientists Sponsorship Program by CAST(2022QNRC001)。
文摘Extensive experimental studies have been performed on the Diels-Alder(DA)reactions in ionic liquids(ILs),which demonstrate that the IL environment can significantly influence the reaction rates and selectivity.However,the underlying microscopic mechanism remains ambiguous.In this work,the multiscale reaction density functional theory is applied to explore the effect of 1-butyl-3-methylimidazolium hexafluorophosphate([BMIM][PF_(6)])solvent on the reaction of cyclopentadiene(CP)with acrolein,methyl acrylate,or acrylonitrile.By analyzing the free energy landscape during the reaction,it is found that the polarization effect has a relatively small influence,while the solvation effect makes both the activation free energy and reaction free energy decrease.In addition,the rearrangement of local solvent structure shows that the cation spatial distribution responds more evidently to the reaction than the anion,and this indicates that the cation plays a dominant role in the solvation effect and so as to affect the reaction rates and selectivity of the DA reactions.
基金the immense support provided by the National Research Foundation of Korea(NRF)Grant funded by the Korean Government(MSIT)(RS-2023–00210114)the National R&D Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(2021M3D1A2051636)。
文摘Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy future.Computational methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic insights.In this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the HER.In addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during HER.These spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.
基金finically supported by the National Natural Science Foundation of China(22075055)the Guangxi Science and Technology Project(AB16380030)。
文摘Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.
