Ellagic Acid-mediated Tracing Preparation Mechanism Of Maillard Intermediate And Regulation Of Pyrazine Formation

Maillard reaction products(MRPs)are commonly used as food flavorings,but their physicochemical properties are unstable and it is difficult to maintain the effect of flavor enhancement.Maillard reaction intermediates(MRIs)has stable physicochemical properties at room temperature.Using Maillard reaction intermediates instead of Maillard reaction products can realize the controlled formation of food fresh flavor.Natural polyphenols can interact with Maillard reaction intermediates to inhibit browning,which has the potential as a tracer for the preparation of Maillard reaction intermediates in aqueous phase.In this paper,the water-phase tracer preparation method of glycine-xylose Maillard reaction intermediates was studied,and the tracer mechanism of inhibiting browning by the interaction between ellagic acid,a polyphenolic compound,and targeted intermediates was clarified.The mechanism of polyphenols affecting the formation of key characteristic flavor substances was further analyzed,and the method for regulating the formation of Maillard flavor was established.The specific research contents are as follows:The two-stage variable temperature Maillard reaction was used,and the browning degree(A420)of Maillard reaction was used as evaluation index.Ellagic acid was selected as the polyphenol with the best browning inhibition effect of Maillard reaction,which could trace the formation of Maillard reaction intermediates.The critical formation conditions of ellagic acid acting on target intermediates were further determined as follows:initial pH 7.4,carbonyl-amino ratio 2:1,water phase reaction at 90℃ for 90 min,and the optimal tracer effect was obtained when the ellagic acid content was 5 mmol/L.By studying the intervention effect of ellagic acid on the variation of different components in the reaction system during heat treatment,it was found that ellagic acid could not react with xylose and glycine,and its target substance was xylose-glycine Maillard intermediate Amadori compound.According to the critical formation conditions of Amadori compound determined by the two-stage variable temperature Maillard reaction,xylose-glycine Amadori compound was further efficiently prepared by thermal reaction and vacuum dehydration coupling technology.The effect of vacuum dehydration reaction time on the yield of Amadori compound was studied,and it was determined that the yield of Amadori compound was the highest at 90℃after 80 min of atmospheric water phase reaction and 10 min of vacuum dehydration reaction.The Amadori compound was prepared under this condition,and its separation,purification and structural characterization were further carried out.The relative molecular mass of the obtained Amadori compound was 207,and the molecular formula was C7H13NO6,and there were 5 isomers in water.The mechanism of ellagic acid inhibiting Maillard browning and tracing xylose-glycine Amadori compound was studied.The ellagic acid/Amadori compound model system was used as research object,and the concentration of Amadori compound and its degradation product glycine during heat treatment were analyzed by high performance liquid chromatography with evaporative light scattering detector.The ellagic acid-Amadori compound interaction product was analyzed by ultra performance liquid chromatograph tandem quadrupole mass spectrometry.It was found that the ellagic acid lactone bond was hydrolyzed and then formed an adduct with Amadori compound through nucleophilic addition reaction.The additive effect inhibited the degradation of Amadori compound and affected the formation of regenerated amino acids.Furthermore,by analyzing the concentration of 1-deoxyosone,3-deoxyosone,glyoxal,and methylglyoxal,the downstream products of Amadori thermal degradation under the intervention of ellagic acid,the effective mechanism of the stabilization of Amadori compound under the addition of ellagic acid was clarified.The capture of Amadori compound by ellagic acid hindered the formation of α-dicarbonyls and inhibited Maillard browning.Ellagic acid was added to the system at the time when xylose-glycine Amadori compound were formed in large quantities.Ellagic acid and Amadori compound formed a large number of adducts,which inhibited the transformation of Amadori compound to melanoidins.At this time,the color of formed Maillard reaction products was the lightest,and the purpose of tracing the formation of aqueous phase of Amadori compound was achieved.Due to the good browning inhibition of ellagic acid,the combination of ellagic acid and Maillard reaction intermediates can develop light color Maillard reaction flavorings and broaden the application of Maillard reaction products in food flavor enhancement.However,the interaction between ellagic acid and Maillard reaction intermediates also affects the formation of Maillard flavor,and the most significant inhibitory effect was on the formation of pyrazines.The mechanism of ellagic acid on pyrazines formation in xylose-glycine Maillard reaction system was studied,and the key pathway of ellagic acid combined with Amadori compound inhibiting the degradation of Amadori compound and inhibiting the formation of pyrazines was clarified.The formation of pyrazines in Maillard reaction of glycine-glyoxal and glycine-methylglyoxal model systems under the intervention of ellagic acid were further studied,and it was found that ellagic acid could promote pyrazines formation.The oxidation of ellagic acid itself could form quinone in the thermal reaction,which promoted the formation of dihydropyrazine to pyrazine.Moreover,with the increase of ellagic acid addition amount,the concentration of pyrazines formation increased,which further proved the effective mechanism of ellagic acid oxidation promote pyrazines formation.The addition of ellagic acid during the accumulation period of Amadori compound in Maillard reaction inhibited pyrazines formation due to its trapping effect on Amadori compound.When ellagic acid was added at the initial stage of Maillard reaction or after the degradation of Amadori compound in the late stage of Maillard reaction,the oxidation of ellagic acid itself promoted pyrazines formation.Based on the above results,a new method for regulating the formation of pyrazines by staged Maillard reaction was proposed.