Study On The Maillard Reaction Of Glutamic Acid And Glucose System Under Mild Conditions

Maillard reaction is of most importance with regard to quality of foods and human healthy,as it plays an important role in color,flavor,taste and nutrition value.The Maillard reaction products?MRPs?have important contributions to the development of flavors,spices,pigments and so on.The current research on the Maillard reaction were focused on the model system under high temperature conditions.The Maillard reaction can produce a variety of key flavors that are important for food under mild conditions of low temperature.However,the occurrence of Maillard reaction and possible reaction mechanism of free amino acids in food during long-term storage is rarely reported.Therefore,it is necessary to explore the possible mechanism of the Maillard reaction of free amino acids in food under mild conditions.In order to study the mechanism of the glutamic acid and glucose Maillard reaction system under mild conditions,the model system of glutamic acid and glucose was constructed by setting different reaction temperature,time and reactants concentration ratio.A series of index of the Maillard reaction products under various reaction conditions,such as p H value,the absorbance,volatile components,the concentration of glucose and non-volatile components were determined.The main results showed as follows:1.Effects of reaction conditions on pH,intermediate products?A294nm,A360nm?of the Maillard reaction of glutamic acid and glucose systemThe pH value of the glutamic acid and glucose Maillard system was relatively stable,which always maintained in the acidic environment.Under the same reaction temperature and reactant concentration,the absorbance value of 294 nm and 360 nm increased with the extension of reaction time,which indicated that intermediates were sharply increased.Under the same reaction time and reactant concentration,the absorbance of this system gradually increased at 10??20??30?,and sharply increased at 40?.Under the same reaction time and temperature,the absorbance of the system was positively correlated with the concentration of the reactants.2.Effects of reaction conditions on volatile components of the Maillard reaction of glutamic acid and glucose systemThe results showed that the volatile products produced in the glutamic acid and glucose system changed at different reaction conditions through the principal component analysis.The volatile product information of the sample under different reaction conditions can be successfully distinguished by the principal component analysis method.Meanwhile,the volatile compounds of the glutamic acid?0.02mol/L?and glucose?0.02mol/L?system was determined by SPME-GC-MS.Under mild conditions,the aldehydes in the volatile flavor compounds produced by the glutamic acid-glucose?0.02 mol/L: 0.02 mol/L?system were relatively high in the kinds number and relative content?%?of the compound species.3.Effects of reaction conditions on non-volatile components of the Maillard reaction of glutamic acid and glucose systemThe non-volatile product information of the glutamic acid and glucose system under different reaction conditions can be successfully distinguished by the discriminant analysis and inferred changes in the non-volatile components of different system.In some systems,there were some regular changes in the non-volatile products.4.Effects of reaction conditions on the glucose concentration of the Maillard reaction of glutamic acid and glucose system and its kinetic modelUnder the same reaction temperature and reactant concentration,the concentration of glucose gradually decreased along with the prolongation of reaction time.Under the same reaction time and temperature,the higher the concentration of reactants,the Maillard reaction was severe,the glucose concentration decreased significantly.The order of glucose concentration difference was from glutamic acid to glucose?0.06mol/L:0.02mol/L?,glutamic acid glucose?0.02mol/L:0.06mol/L?,glutamic acid glucose?0.02mol/L:0.02mol/L?.The glucose concentration followed the Boltzmann model with the temperature and time,which can be reasonably used to predict the reaction process..The kinetic equation was y=A₂+?A₁-A₂?/?1+exp??x-x₀?/d_x??.