The Role And Mechanism Of Enzymatic Hydrolysate Components In The Formation Of Thermal Reaction Meat Flavor

In this paper,to study the contribution of amino acids and peptides with different molecular weight to the formation of flavor and taste with the addition of oxidized chicken fat.And to study the contribution of other amino acids to the formation of meat flavor in the “cysteine+reducing sugar” maillard reaction.The research results have some guiding significance for optimizing the preparation technology of meat flavors and preparing better flavor flavors.Based on the preparation of amino acids and different molecular weight peptide components from chicken enzymatic hydrolysate,two kinds of model thermal reaction systems of chicken fat without oxidation and chicken fat with oxidation were designed to compare the contribution of chicken enzymatic hydrolysate components on the formation of meat aroma in thermal reaction.For the reaction products,the changes of browning and p H values were measured,and the volatile flavor components were analyzed by solid phase microextraction(SPME)and gas chromatography-mass spectrometry(GC-MS).It showed that for both the two types of reactions,with the increase of molecular weight of the aminocontaining samples,the changes of browning and the amounts of generated sulfur-containing compounds and nitrogen-containing heterocyclic compounds were decreased.Among them,the free amino acid samples behaved the best in the generation of sulfur-containing compounds,and the < 1 k Da peptides samples behaved the best in the generation of pyrazine compounds.Thus it is concluded that amino-containing precursors with larger molecular weights in the enzymatically hydrolyzed chicken have a lower reactivity.On the other hand,in comparsion,with the addition of oxidized chicken fat,the changes of browning of the reactions were just slightly increased;while the amounts of the generated flavor compounds were considerably decreased,which led to smaller differences between the 1 k Da and 1-5 k Da fractions in formation of the pyrazine compounds,and almost no contribution to meat flavor formation for the > 5 k Da peptide fraction.The decrease phenomena in flavor formation with the addition of oxidized chicken fat was attributed to inhibition effect from the lipid degradation products in the oxidized chicken fat on the Maillard reaction.Based on enzymatic hydrolysate components from chicken enzymatic hydrolysis,“enzymatic hydrolysate components + xylose”,“enzymatic hydrolysate components + oxidized chicken fat”,“enzymatic hydrolysate components + solvent-assisted flavor evaporation(SAFE)concentrated solution from oxidized chicken fat”,“enzymatic hydrolysate components + octadecanal”,“enzymatic hydrolysate components + xylose + oxidized chicken fat”,“enzymatic hydrolysate components + xylose + SAFE concentrated solution from oxidized chicken fat” and “enzymatic hydrolysate components + xylose + octadecanal” reaction systems were designed to study the effect of meat enzymatic hydrolysate components on the taste of thermal reaction products.By monitoring the changes of browning,p H value of the system,it was found that the higher reaction rate was the thermal reaction system with xylose and octadecanal added at the same time.The sensory evaluation of the thermal reaction products showed that in the thermal reaction system of enzymatic hydrolysis powder,the thermal reaction system of “enzymatic hydrolysis powder + xylose + SAFE concentrated solution from oxidized chicken fat” had stronger meat flavor and thickness.In the thermal reaction system of different molecular weight peptide components,“1-5 k Da peptide component + xylose + octadecanal” thermal reaction system was the stronger thickness,followed by “0.2-1 k Da peptide component + xylose + octadecanal”.Based on “cysteine+xylose” system and “cysteine+xylose” system with enzymatic hydrolysis powder as substrate,the other free amino acids were added to the system.To study the effects of other free amino acid components on the formation of meat flavor and taste of thermal reaction products.By monitoring the changes of browning,p H value of the system,it was found that all the reaction systems with higher reaction rate were those with lysine added.By monitoring the volatile flavor components,it showed that the total amount of sulfur compounds produced by the reaction system containing glutamic acid was higher,and the maximum sulfur compounds were obtained when the concentration of glutamic acid was 4 times higher than cysteine.In the aroma extract dilution analysis(AEDA)of gas chromatography-olfactometry(GC-O)analysis,the compounds found with high flavor dilution factors(FD ? 256)were 2-methyl-3-furanthiol,3-mercapto-2-pentanone,2-furfurylthiol,3-thiophenethiol,bis(2-methyl-3-furyl)disulfide.