Interactions Between Heterocyclic Amines And Advanced Glycation Endproducts In Roasted Meat Matrixes And Model Systems

Many different types of harmful Maillard reaction products such as heterocyclic amines（HAs）and advanced glycation endproducts（AGEs）commonly exist in heat-processed meat products,but most of the current studies focus on just one type of harmful Maillard reaction product.To simultaneously control different types of harmful Maillard reaction products at the same time,it is necessary to clarify the interaction effect of these harmful products in the process.Furthermore,when an inhibitor was used,a clear understanding of the interaction problems was lacking.HAs and AGEs share precursors,reaction pathways,and intermediates of common active carbonyl intermediates.Theoretically,interaction exists in the reaction pathways.On this basis,we used multi-response dynamic modeling and stable isotope labeling to investigate the simultaneous generation rules of HAs and AGEs in model systems,with the goal of elucidating the interaction between HAs and AGEs in the presence of reaction precursors.Then,using multi-response kinetic modeling,the interaction effect of epigallocatechin gallate（EGCG）on HAs and AGEs in model systems was investigated.Finally,the kinetics of the formation of HAs and AGEs in roasted beef patties was investigated,as well as the effects of polyphosphates and sodium chloride on the formation of these two types of harmful Maillard reaction products.Two types of HAs are imidazoquino（xa）line and pyridine compounds,and two typical AGEs are Nε-carboxymethyl-lysine（CML）and Nε-carboxyethyl-lysine（CEL）.In this paper,simultaneous generation of imidazoquino（xa）line and AGE model systems（lysine/threonine/glucose/creatinine）（IQ-A system）was established.Multi-response kinetics modeling was based on the establishment of mechanism models and changes in the content of precursors,α-dicarbonyl compounds,2,5-dimethylpyrazine intermediates,and the final products（CML,CEL,Me IQx,7,8-Di Me IQx,and 4,8-Di Me IQx）.The interaction between HAs and AGEs was elucidated using the calculated kinetic parameters.It was found that the rate constant of glucose pyrolysis to methylglyoxal was smaller than that of Amadori rearrangement degradation.At 150℃,the reaction rate constant of CML through the oxidation pathway of the Amadori rearrangement product(k₇=3.794×10^-3 min^-1)was twice that of CML generation through the reaction of glyoxal and lysine(k₈=1.815×10^-3 L mol^-1 min^-1).However,as the reaction temperature increases,k₈ approaches k₈;Me IQx,7,8-Di Me IQx,and 4,8-Di Me IQx had the lowest rate constants(9.831×10^-10–1.305×10^-7 L mol^-1 min^-1).These results indicated that the formation of methylglyoxal is mainly due to the degradation of Amadori rearrangement products.CML was mainly generated by oxidation of Amadori rearrangement products at low temperatures,and the contribution of the oxidation pathway of Amadori rearrangement products and glyoxal and lysine reaction pathway to CML was equally important when the temperature increased.The formation of HAs via the reaction between pyrazine and creatinine is a key rate-limiting step.A pyridine HA（2-amino-y1-methyl-6-phenylimidazo[4,5-b]pyridine[Ph IP]）and AGE simultaneous generation system（lysine/phenylalanine/glucose/creatinine）（PA system）was also established,and the interaction relationship was investigated by multi-response dynamic modeling.Multi-response kinetic modeling was based on the reaction network established and the content of precursors,α-dicarbonyl compounds,phenylacetaldehyde,and final products（CML,CEL,and Ph IP）.It was found that the rate constant of CML formation from glyoxal reaction with lysine（k₆）was less than that from oxidation of Amadori rearrangement of Maillard reaction intermediates(k₁₀)(7.264×10^-3,1.317×10^-2,and 2.241×10^-2 min^-1).The rate constants(k₁₁)of CEL generation by oxidation of Amadori rearrangement product(5.807×10^-3[200℃],8.704×10^-3[200℃],1.250×10^-2[200℃]min^-1)are greater than the rate constant（k₅）(k₁₁>k₅).The reaction of phenylacetaldehyde with creatinine to form Ph IP has the lowest rate constant.These results indicated that CML was mainly derived from the oxidation of Amadori rearrangement products,and its contribution increased with increasing temperature.The oxidation pathway of Amadori rearrangement products contributed more to CEL than the reaction between phenylacetaldehyde and lysine.The reaction of creatinine with phenylacetaldehyde is a rate-limiting step in the Ph IP pathway.These two kinetic models illustrate the interaction between the two kinds of harmful Maillard reactions.A stable isotope recording experiment with[U-¹³C₆]glucose was used to clarify the distribution of precursor glucose carbon atoms in the reaction products of HA and AGE model systems.Analysis of the reaction products by LC-MS or GC-MS indicated that glucose formed pyruvaldehyde in the form of C₃ fragments.Most of the carbon in 2,5-dimethylpyrazine was derived from C₃/C₃of glucose pyrolysis.C₂ and C₃ fragments of glucose pyrolysis were involved in three carbon atoms of the CML carboxymethyl group and the CEL carboxyethyl group,respectively.The C₃/C₁ fragment of glucose or two C₃ and one C₁ fragment is involved in Me IQx production;The carbon atoms in glucose did not enter phenylacetaldehyde and Ph IP molecules.The effects of EGCG on the simultaneous generation of imidazoquino（xa）line HA and AGE system（IQ-A system）and the PA system were investigated.The multi-response kinetics of the IQ-A system at 200℃indicated that the rate constants of oxidation（k₇）from the Amadori rearrangement product and CML from the glyoxal and lysine reaction（k₈）increased by 681%and 1006%,respectively.The degradation rate constant(k₁₃)of CML was increased by 766%(k₁₃>k₇ and k₈).These results suggested that the inhibition of CML by EGCG at high temperatures might be related to the pathway promoting CML degradation.The rate constants of Me IQx,7,8-Me IQx,and 4,8-Me IQx formation(k₁₅,k₁₆,and k₁₇)decreased by 40%,40%,and 44%,respectively,in the presence of EGCG,suggesting that EGCG could inhibit the reaction of 2,5-dimethylpyrazine with creatinine.The effect of EGCG on the dynamics of the PA system indicated that the rate constant of the glyoxal and lysine reaction to generate CML increases by about 65%in the presence of EGCG.EGCG can reduce the rate constant（k₈）of the reaction between phenylalanine and methylglyoxal to form phenylacetaldehyde by 75%and the rate constant of the reaction between phenylacetaldehyde and lysine(k₁₂)decreased by 88%.Therefore,EGCG can inhibit the reaction between phenylalanine and methylglyoxal and promote the degradation of phenylacetaldehyde,thus reducing the content of phenylacetaldehyde.In the presence of EGCG,the rate constant of Ph IP formation from the reaction of phenylacetaldehyde and creatinine decreased by 77%,which significantly inhibited Ph IP formation.To investigate the formation of HAs and AGEs in meat products,dynamic changes in HAs and AGEs were investigated in beef patties roasted at 150°C,175°C,200°C,and 225°C for 5–50 min（1/2 total time for each side）.The results indicated that the formation of HAs and AGEs in roasted beef was in accordance with first-order reaction kinetics.Me IQx and Ph IP had higher activation energies(34.12±7.86 and 28.19±8.07 k J mol^-1)and were more sensitive to temperature.However,CML and CEL have lower activation energies(19.55±5.25 and9.36±0.41 k J mol^-1),which are less dependent on temperature and can be formed at relatively low temperatures.The Eyring equation was used to investigate the relationship between the rate constant and the temperature;the activation entropy of HAs and AGEs is less than 0,indicating that the formation of these two kinds of harmful Maillard reaction products follows a bimolecular mechanism.Finally,the effects of different ionic strengths of sodium tripolyphosphate（TPP）,sodium pyrophosphate（PP）,and NaCl on HAs and AGEs in roasted beef patties were investigated.The results showed that after roasting at 225℃for 20 min,adding NaCl and（or）polyphosphate with different ionic strengths could significantly reduce cooking loss and increase the moisture content,increase the hardness of the patties,increase the surface temperature of the patties,the higher the ionic strength of the patties.NaCl and polyphosphate significantly increased the content of Ph IP,imidazoquino（xa）line（Me IQx,4,8-Di Me IQx,and IQ）,β-carboline（harman and norharman）,total HAs,CML,and CEL（P<0.05）.Principal component analysis and correlation analysis showed that the content of Ph IP,Me IQx,4,8-Di Me IQx,IQ,harman,norharman,CML,and CEL were significantly correlated with the moisture content and cooking loss of beef patties treated with polyphosphate and NaCl（P<0.05）.The increase in the content of HAs,CML,and CEL in beef patty may be related to the pro-oxidation effect of salt,but the main reason is that the surface temperature of the beef patty is increased by high ionic strength.