The effect of high pressure on the formation of volatile products in a model Maillard reaction

Reaction progress in the formation and subsequent decay of several of the v olatile products from a model Maillard reaction between lysine and xylose h as been followed at pH 7 and 10 and at elevated pressures. At low pH, the b uildup and decay of 5-methyl-4-hydroxy-3(2H)-furanone and several minor pro ducts were observed. The application of high pressure results in a much dim inished maximum concentration of each although the time to the maximum is u naffected. At pH 10, products contain nitrogen heterocycles with 2-methylpy razine being the principal one which builds up and only slowly decays with time. Again, the yield is greatly reduced by pressure. The results are inte rpreted in terms of the inhibition by pressure of the formation of the prec ursor, the Amadori rearrangement product which affects subsequent products. In some instances rates of formation are also found to be slightly inhibit ed while degradation of these products is accelerated. The corresponding me chanisms are examined in the light of these results.