Reaction Mechanism of Maillard Reaction between Glucosamine and Sulfur-containing Amino Acids

Abstract

Maillard reaction is an important reaction in food industry. It is responsible for the formation of color and aroma, as well as toxic compounds as the recent discovered acrylamide. The knowledge of reaction condition to maximize Maillard reaction to form optimum browning and aroma is very important in food processing industry. Maillard reaction is mainly influenced by many factors such as temperature, pH, water activity, heating time, buffer concentration, reactant concentrations and reactant source and sugar involved to the reaction. Even though lots of experiments have been done on this complex network of chemical reactions, very few papers is available on Maillard reaction between glucosamine and sulfur-containing amino acids. Optimization of Maillard reaction conditions and identification of Maillard reaction products are presented in each of the chapters. The reaction condition of initial pH, reaction time, reaction temperature and reactant concentration ratio was subjected to optimize by using response surface methodology in aqueous model systems. Maillard reaction between glucosamine and cysteine (chapter 1) was optimized and found that initial pH and the concentration ratio of the reactants have the significant effects on Maillard reaction. The central composite design matrix showed that the optimum absorbance can be achieved with the independent variable set at 1.30 concentration ratio, initial pH 8.01, temperature 1110C and 2.47 hr reaction time. Its optimum color change can be achieved by the independent variable set at concentration ratio 1.30, initial pH 8.01, temperature 1110C and reaction time 2.47 hours. Sulfur dioxide, methanethiol, carbon disulfide, methanesulfonic anhydride, and ethylene sulfide were identified in Maillard reaction products of glucosamine and cysteine. The optimum conditions for Maillard reaction between glucosamine and methionine are described in chapter 2. Maillard reaction between glucosamine and methionine was optimized and found that the linear coefficient of pH, reaction time, and reaction temperature and concentration ratio were significant. The optimal reaction conditions for absorbance were 113.90C reaction temperature, 1.76 hr reaction time, initial pH 8.4 and 1.26 concentration ratio of reactants. The optimal reaction conditions for color development were 93.20C reaction temperature, 1.9 hr reaction time, initial pH 6.18 and 0.9 concentration ratio of reactants. The effect of initial pH on Maillard reaction between glucosamine and sulfur-containing amino acids were studied in Chapter 3. Cysteine, methionine and taurine were reacted at fixed reaction temperature, concentration ratio and reaction time, while pH was varied at pH 5, pH 7 and pH 9. Flavor volatiles were isolated and identified by using GC-MSD. Maillard reaction between glucosamine and taurine showed the highest amount of different kinds of sulfur-containing volatile compounds.