| a-Dicarbonyl compounds are important intermediates of Maillard reaction which are easily found from carbohydrate-rich or lipid-rich foods especially at high temperature . a-Dicarbonyl compounds are important precursors of acrylamide,4(5)-hydroxymethyfurfural which are carcinogenity substances produced by Maillard reaction. In this paper, the model system of carbohydrate (monosaccharide, disaccharide,oligosaccharide, polysaccharide) and lysine reacting at different temperature (120?, 140?,160?, 180?) and different heating time (10min, 20min, 30min) was studied. Exploring the regulation and mechanism of a-dicarbonyl compounds could provide the basic for controlling the hazardous substances. In this experiment, the most normal a-dicarbonyl compounds (3-deoxyglucosone, glyoxal, methyglyoxal and 2,3-butanedione) were studied among various kinds of which had been found already.The results showed that at the same heating time, the total amount of a-dicarbonyl compounds was increased with the increasing temperature. Glucose, fructose, ribose and maltose could produce the most amount of a-dicarbonyl compounds when heated at 180?for 10min, while sucrose, dextrin and starch could produce the most amount when heated at 180? for 30min. The rough order that carbohydrate produced a-dicarbonyl compounds at above 120? was fructose>glucose>maltose>ribose>sucrose>?-dextrin>starch. Compared with disaccharides, the amount of a-dicarbonyl compounds that maltose produced was much more than sucrose. The highlight of this study was the adding of starch,a kind of polysaccharide. Starch was abundant in actual consumption food such as cookies, steamed stuffed bun and bread which contained more starch than the general saccharides. The experiment found that the concentration of a-dicarbonyl compounds produced by starch during the heating process was increased with the increasing heating time and temperature.So the kind of starch food was not suitable for heating for long time and/or at high temperature which would increase the proportion of decomposition and the content of a-dicarbonyl compounds would also increase.Compared with four kinds of a-dicarbonyl compounds, methyglyoxal was the most adequate one. Starch and ribose couldn't produce 3-deoxyglucosone while heating.Fructose and glucose could produce more 3-deoxyglucosone and methyglyoxal than other saccharides, while ribose and maltose could produce more glyoxal, and 2,3-butanedione than others. While heating for long time or high temperature, the amount of 3-deoxyglucosone decreased which indicated its unstable structure. The increasing rate of a-dicarbonyl compounds was lowest at the process of heating from 140? to 160?compared with the process from 160? to 180? .So the heating temperature had better below 160?. |
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