A kinetic model for N-(1-deoxy-D-fructos-1-yl)-glycine (DFG) thermal decomposition was proposed. Two temperatures (100 and 120 degrees C) and two pHs (5.5 and 6.8) were studied. The measured responses were DFG, 3-deoxyosone, 1-deoxyosone, methylglyoxal, acetic acid, formic acid, glucose, fructose, mannose and melanoidins. For each system the model parameters, the rate constants, were estimated by non-linear regression, via multiresponse modelling. The determinant criterion was used as the statistical fit criterion. Model discrimination was performed by both chemical insight and statistical tests (Posterior Probability and Akaike criterion). Kinetic analysis showed that at lower pH DFG 1,2-enolization is favoured whereas with increasing pH 2,3-enolization becomes a more relevant degradation pathway. The lower amount observed of 1-DG is related with its high reactivity. It was shown that acetic acid, a main degradation product from DFG, was mainly formed through 1-DG degradation. Also from the estimated parameters 3-DG was found to be the main precursor in carbohydrate fragments formation, responsible for colour formation. Some indication was given that as the reaction proceeded other compounds besides DFG become reactants themselves with the formation among others of methylglyoxal. The multiresponse kinetic analysis was shown to be both helpful in deriving relevant kinetic parameters as well as in obtaining insight into the reaction mechanism.

中文翻译：

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Amadori N-（1-脱氧-D-果糖-1-基）-甘氨酸降解途径的动力学模型。第二部分-动力学分析。

提出了N-（1-脱氧-D-果糖-1-基）-甘氨酸（DFG）热分解的动力学模型。研究了两个温度（100和120摄氏度）和两个pH（5.5和6.8）。测得的响应是​​DFG，3-脱氧松酮，1-脱氧松酮，甲基乙二醛，乙酸，甲酸，葡萄糖，果糖，甘露糖和黑色素。对于每个系统，通过多响应建模，通过非线性回归估算模型参数，即速率常数。行列式标准用作统计拟合标准。通过化学观察和统计检验（后验概率和Akaike准则）进行模型判别。动力学分析表明，在较低的pH值下，DFG有利于1,2-烯化，而随着pH值的升高，2,3-烯化成为更相关的降解途径。观察到的1-DG含量较低与其高反应性有关。结果表明，乙酸是DFG的主要降解产物，主要是通过1-DG降解形成的。另外，根据估计的参数，发现3-DG是碳水化合物片段形成中的主要前体，其负责颜色形成。有迹象表明，随着反应的进行，除DFG外，其他化合物本身也成为反应物，并形成了甲基乙二醛。结果表明，多响应动力学分析不仅有助于推导相关的动力学参数，而且有助于深入了解反应机理。另外，根据估计的参数，发现3-DG是碳水化合物片段形成中的主要前体，其负责颜色形成。有迹象表明，随着反应的进行，除DFG外，其他化合物本身也成为反应物，并形成了甲基乙二醛。结果表明，多响应动力学分析不仅有助于推导相关的动力学参数，而且有助于深入了解反应机理。另外，根据估计的参数，发现3-DG是碳水化合物片段形成中的主要前体，其负责颜色形成。有迹象表明，随着反应的进行，除DFG外，其他化合物本身也成为反应物，并形成了甲基乙二醛。结果表明，多响应动力学分析不仅有助于推导相关的动力学参数，而且有助于深入了解反应机理。