| Using maillard reaction to prepare fragrance with specific flavors has extensive application in the food industry, however, maillard reaction can also produce α-dicarbonyl compounds and other harmful substances. It’s of great significance to prepare target flavors using maillard reaction while reduce the generation of hazardous compounds. α-dicarbonyl compound can be formed by the caramelization reaction(the aldol condensation or sugar autoxidation process) of monosaccharides, oligosaccharides or polysaccharides. It can also be produced by the pyrolysis of Amadori intermediates generated during maillard reaction. This thesis investigated the regularity of sweet flavor compounds and α-dicarbonyl compounds as well as their relationship of three maillard reaction model systems(glucose-glycine, glucose-alanine and glucose-ammonium hydroxide), so as to reduce the formation of hazardous substances when prepare sweet flavor compounds. It’s important for the safety control of the preparation of specific flavor compounds.HPLC was employed to investigate the generation regularity of three α-dicarbonyl compounds(glyoxal, GO; methylglyoxal, MGO; 3-deoxyglucosone, 3-DG) of three reaction systems under different reaction conditions(temperature, initial pH value, reaction duration and the ratio of reactants). The results showed that the increase of reaction temperature promoted the formation of three α-dicarbonyl compounds of maillard reaction systems in the range of 80~140oC, but the content of 3-DG reduced when the reaction temperature reached 110 oC or 120 oC. The production of 3-DG decreased when the initial pH value was above 6, but it slowly promoted the generation of GO and MGO. The content of 3-DG, GO and MGO increased during the increasing of reaction duration. the content of these three α-dicarbonyl compounds remained almost the same when the reaction duration reached 120 min.The content of 3-DG of glucose-glycine and glucose-alanine system gradually increased during the increasing of the proportion of glucose and amino acid levels, while the generation of GO and MGO was supressed. But in the glucose-ammonia hydroxide system, the content of three α-dicarbonyl compounds increased during the increasing of the proportion of glucose and amino acid.Solid phase microextraction-gas chromatography-mass spectrometry(SPME-GC-MS) was utilized to explore the generation regularity of typical sweet flavor compounds such as furans and furanones as well as other main flavor compounds including aldehydes, ketones and pyrazines under different reaction conditions(reaction temperature, initial pH value, reaction duration and the ratio of reactants) of three maillard reaction model systems. The results showed that the increase of temperature accelerated the generation of major flavor compounds, in particular the ketones and pyrazines, but the amount of furans and furanones increased relatively slowly. The effect of initial pH on the generation of flavors of the three systems was diffferent. The increase of initial pH accelerated the generation of pyrazines of glucose-glycine and glucose-alanine system, and the production of furans and furanones were less than pyrazines and remained constant. The increase of initial pH was bad for the generation of aldehydes and ketones of glucose-glycine system, but promoted their generation in the glucose-alanine system. The production of ketones, furans, furanones and pyrazines of glucose-ammonia hydroxide system were maximum under neutral conditions. Within reaction duration of 120 min, the content of ketones and pyrazines increased with the increasing of reaction duration, but the content of the aldehydes, furans and furanones changed slightly in the entire reaction duration. The increase of the ratio of glucose and amino acid or ammonia hydroxide concentration promoted the generation of furans and decreased the generation of pyrazines.Correlation analysis was used to examine the association regularity between α-dicarbonyl compounds and the main flavor compounds of the three model systems.The results showed that for the glucose-glycine system, GO and the flavor compounds(furans, furanones, pyrazines) presented a significant positive correlation under different reaction temperature(p≤0.05). GO and the flavor compounds(furanones and pyrazines) showed a significant correlation(furanone: negative correlation p≤0.05, pyrazine: positive correlation p≤0.01) under different initial reaction pH value; MGO and the flavor compounds(furans, furanones, pyrazines) showed a significant positive correlation under different reaction duration(p≤0.05). MGO and furans showed a significant negative correlation when the concentration ratio of glucose and glycine changed(p≤0.05); For glucose-alanine system, 3-DG and the flavor compounds(furans, furanones, pyrazines) showed a significant positive correlation under different reaction duration(furans: p≤0.05, furanones and pyranzines:p≤0.01). GO and furanones showed a significant positive correlation when the initial pH value changed(p≤0.05), and had a positive correlation with the three kinds of flavor compounds under different reaction duration(p≤0.05), also GO had a significant negative correlation with furans when the concentration ratio of glucose and alanine changed(p≤0.05). MGO had a significant positive correlation with the flavor compounds(furans, furanones, pyrazines) under different reaction duration(p≤0.01); For the glucose-ammonia hydroxide system, 3-DG had a significant positive correlation with the flavors(furans, furanones, pyrazines) when the reaction duration changed(furans: p≤0.05, furanones and pyrazines: p≤0.01). GO had a significant positive correlation with the flavor compounds(furanones, pyrazines) during the different reaction duration(furanones: p≤0.05, pyrazines: p≤0.01). MGO had a significant positive correlation with the flavor compounds(furans, furanones, pyrazines) when the reaction temperature changed(p≤0.01) and the flavor compounds(furanones, pyrazines) under different reaction duration(p≤0.01).The research showed that the increase of the reaction duration and temperature would promote the generation of α-dicarbonyl compounds and the main flavors. But it reduced the GO generation and promoted the furanones generation when reduced the initial reaction pH value(glucose-glycine system). While increasing the ratio of the glucose and amino acid concentration, it would help to reduce the concentration of GO(glucose-alanine system) and MGO(glucose-glycine system) generation and improve the productivity of furans. |
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