Dual role of exogenous xylose in regulating pyrazines and furans formation during the thermal degradation of Nα,Nε-di(1-deoxy-d-xylulos-1-yl)lysine through temperature, reaction time, and xylose concentration control

Exogenous xylose exhibited a significant temperature-dependent regulatory effect on the furans and pyrazines formation during the degradation of dual-glycated Amadori rearrangement product of lysine (Lys), N α ,N ε -di(1-deoxy- d -xylulos-1-yl)lysine ( N α ,N ε -di-Xul-Lys ARP). At 100 °C, xylose primarily enhanced the dehydration pathway of deoxypentosone. This significantly increased furans yield, while delaying lysine release by interacting with mono-glycated Lys-ARPs, thereby inhibiting the early formation of pyrazines. 120 °C accelerated the dehydration and retro-aldolization of deoxypentosone, markedly boosting furans formation and further promoting the substantial production of α -dicarbonyl compound with extra-added xylose. Additionally, xylose buffered the rapid pH decline, enhancing the α -aminoketones electrophilicity and facilitating pyrazines formation in N α ,N ε -di-Xul-Lys ARP. At 140 °C, xylose hindered furans formation but notably increased methylpyrazine levels during 30–60 min. Furthermore, increasing the xylose concentration to 60 mmol/L at 120 °C markedly enhanced glyoxal and methylglyoxal production, yielding the highest pyrazine concentration of 98.04 μg/L within 60 min.