Simultaneously Enhanced Formation of Pyrazines and Furans during Thermal Degradation of the Glycyl-<scp>l</scp>-glutamine Amadori Compound by Selected Exogenous Amino Acids and Appropriate Elevated Temperatures
Xue Xia, Tong Zhou, Han Zhang, Heping Cui, Foxin Zhang, Khizar Hayat, Xiaoming Zhang, Chi‐Tang Ho
Abstract
The Amadori compound of glucose and glycyl- l -glutamine (Gly-Gln-ARP) was prepared and characterized by UPLC–MS/MS and NMR. Gly-Gln-ARP could be thermally degraded into Gly-Gln and other secondary reaction products like glycyl- l -glutamic acid and its ARP via deamidation. The thermal processing temperature exerted a tremendous influence on the flavor formation of ARP. Furans were mainly formed at 100 °C, while an elevated temperature of 120 °C facilitated the massive accumulation of α-dicarbonyl compounds through the retro-aldolization of deoxyglucosone, and then increased the formation of pyrazines. The extra-added amino acids further promoted the formation of pyrazines at 120 °C, especially Glu, Lys, and His, further increasing the total concentration of pyrazines to 457 ± 6.26, 563 ± 65.5, and 411 ± 59.2 μg/L, respectively, exceeding the pure heated control at 140 °C (296 ± 6.67 μg/L). The total concentration of furans was enhanced to (20.7 × 10 3 ) ± 8.17 μg/L by extra-added Gln. Different increasing effects were observed on the type and flavor intensity of formed pyrazines and furans from different extra-added amino acids.