Amadori rearrangement products of asparagine with glucose (Asn-Glc-ARP) were first prepared through Maillard model reactions and identified via liquid chromatography–mass spectroscopy. With the study on the effect of the reaction temperature, pH values, and reaction time, the ideal reaction condition for accumulation of Asn-Glc-ARP was determined at 100 °C for 40 min under pH 7. Asparagine (Asn) was prone to degrade from Asn-Glc-ARP in alkaline pH values within a lower temperature range, while in an acidic environment with high temperatures, deamidation of Asn-Glc-ARP to Asp-Glc-ARP (Amadori rearrangement products of aspartic acid with glucose) was displayed as the dominant pathway. The deamidation reaction on the side chain of the amide group took place at Asn-Glc-ARP and transferred it into the hydroxyl group, forming Asp-Glc-ARP at the end. Considering that lyophilization as pretreatment led to limited water activity, a single aspartic acid was not deamidated from Asn directly nor did it degrade from Asp-Glc-ARP even at 120 °C. The degradation of Asn-Glc-ARP through tandem mass spectrometry (MS/MS) analysis showed the obvious fragment ion at m/z 211, indicating that the stable oxonium ion formed during fragmentation. The structure of Asn-Glc-ARP was proposed as 1-deoxy-1-l-asparagino-d-fructose after separation and purification. Also, the content of Asn-Glc-ARP within dry jujube fruit (HeTianYuZao) was quantitated as high as 8.1 ± 0.5 mg/g.

中文翻译：

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天冬酰胺-葡萄糖 Amadori 化合物：干枣果中的形成、表征和分析

天冬酰胺与葡萄糖的阿马多里重排产物（Asn-Glc-ARP）首先通过美拉德模型反应制备，并通过液相色谱-质谱法进行鉴定。通过研究反应温度、pH值和反应时间的影响，确定了Asn-Glc-ARP积累的理想反应条件为100℃、pH 7、40min。在碱性pH值下，Asn-Glc-ARP在较低温度范围内降解，而在高温酸性环境下，Asn-Glc-ARP脱酰胺为Asp-Glc-ARP（天冬氨酸与葡萄糖的Amadori重排产物）显示为主导途径。酰胺基侧链在Asn-Glc-ARP处发生脱酰胺反应，转移到羟基上，最终形成Asp-Glc-ARP。考虑到冻干作为预处理导致水活度有限，单个天冬氨酸不会直接从 Asn 脱酰胺，即使在 120 °C 也不会从 Asp-Glc-ARP 降解。通过串联质谱（MS/MS）分析Asn-Glc-ARP的降解结果显示在m / z 211处有明显的碎片离子，表明碎片过程中形成了稳定的氧鎓离子。经分离纯化后，Asn-Glc-ARP的结构为1-脱氧-1- l-天冬酰胺-d-果糖。此外，干枣果 (和田玉枣) 中 Asn-Glc-ARP 的含量高达 8.1 ± 0.5 mg/g。