The intervention of cysteine (Cys) on the formation of 2,3-butanedione and pyrazines was evaluated during the thermal processing of the alanine-xylose Amadori compound (AX-ARP). With the involvement of Cys, the competitive formation of 2,3-butanedione and pyrazines was induced. The formation of 2,3-butanedione in the AX-ARP/Cys model was suppressed due to the inhibitory effect of the precursors of 2,3-butanedione like deoxypentosones, while the added Cys in the AX-ARP/Cys model competed with the recovered alanine (Ala) to capture glyoxal and methylglyoxal to make up for the absence of pyrazines in the AX-ARP model at an initial pH value of 7. The content of pyrazines increased from 0 up to 16.48 μg/L (120 °C, 120 min). Exogenous Cys itself showed lower reactivity with 2,3-butanedione through the Strecker degradation reaction; while the pH was increased to 8, the degradative products of Cys were facilitated to consume the residual 2,3-butanedione giving rise to the formation of 2,4,5-trimethylthiazole at 120 °C. It was the degradative products of Cys that accelerated the reaction for consumption of 2,3-butanedione rather than Cys itself. Additionally, the inhibitory effect of Cys on 2,3-butanedione formation was weakened under a basic condition, while the promotional effect on the formation of pyrazines was further boosted. With more Cys participating in the process of AX-ARP thermal degradation, the formation of 2,3-butanedione was further inhibited, while the yields of pyrazines were increased.

中文翻译：

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在丙氨酸-木糖 Amadori 化合物的热加工过程中通过添加半胱氨酸的干预竞争形成 2,3-丁二酮和吡嗪

在丙氨酸-木糖 Amadori 化合物 (AX-ARP) 的热处理过程中评估了半胱氨酸 (Cys) 对 2,3-丁二酮和吡嗪形成的干预作用。在Cys的参与下，诱导了2,3-丁二酮和吡嗪的竞争形成。AX-ARP/Cys 模型中 2,3-丁二酮的形成由于 2,3-丁二酮前体如脱氧戊酮的抑制作用而受到抑制，而 AX-ARP/Cys 模型中添加的 Cys 与回收丙氨酸 (Ala) 以捕获乙二醛和甲基乙二醛，以弥补初始 pH 值为 7 时 AX-ARP 模型中吡嗪的缺失。吡嗪的含量从 0 增加到 16.48 μg/L（120 °C， 120 分钟）。通过 Strecker 降解反应，外源性 Cys 本身与 2,3-丁二酮的反应活性较低；当 pH 值增加到 8 时，Cys 的降解产物有利于消耗残留的 2,3-丁二酮，从而在 120 °C 下形成 2,4,5-三甲基噻唑。是 Cys 的降解产物加速了消耗 2,3-丁二酮的反应，而不是 Cys 本身。此外，Cys对2,3-丁二酮生成的抑制作用在碱性条件下减弱，而对吡嗪生成的促进作用进一步增强。随着更多的Cys参与AX-ARP热降解过程，进一步抑制了2,3-丁二酮的生成，同时提高了吡嗪类化合物的产率。是 Cys 的降解产物加速了消耗 2,3-丁二酮的反应，而不是 Cys 本身。此外，Cys对2,3-丁二酮生成的抑制作用在碱性条件下减弱，而对吡嗪生成的促进作用进一步增强。随着更多的Cys参与AX-ARP热降解过程，进一步抑制了2,3-丁二酮的生成，同时提高了吡嗪类化合物的产率。是 Cys 的降解产物加速了消耗 2,3-丁二酮的反应，而不是 Cys 本身。此外，Cys对2,3-丁二酮生成的抑制作用在碱性条件下减弱，而对吡嗪生成的促进作用进一步增强。随着更多的Cys参与AX-ARP热降解过程，进一步抑制了2,3-丁二酮的生成，同时提高了吡嗪类化合物的产率。