Moreira Ana S P, Nunes Fernando M, Simões Cristiana, Maciel Elisabete, Domingues Pedro, Domingues M Rosário M, Coimbra Manuel A
QOPNA, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
CQ-VR, Chemistry Research Centre, Department of Chemistry, University of Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal.
Food Chem. 2017 Jul 15;227:422-431. doi: 10.1016/j.foodchem.2017.01.107. Epub 2017 Jan 23.
Under roasting conditions, polysaccharides depolymerize and also are able to polymerize, forming new polymers through non-enzymatic transglycosylation reactions (TGRs). TGRs can also occur between carbohydrates and aglycones, such as the phenolic compounds present in daily consumed foods like coffee. In this study, glycosidically-linked phenolic compounds were quantified in coffee melanoidins, the polymeric nitrogenous brown-colored compounds formed during roasting, defined as end-products of Maillard reaction. One third of the phenolics present were in glycosidically-linked form. In addition, the roasting of solid-state mixtures mimicking coffee beans composition allowed the conclusion that proteins play a regulatory role in TGRs extension and, consequently, modulate melanoidins composition. Overall, the results obtained showed that TGRs are a main mechanism of phenolics incorporation in melanoidins and are inhibited by amino groups through Maillard reaction.
在烘焙条件下，多糖会发生解聚，同时也能够聚合，通过非酶转糖基化反应（TGRs）形成新的聚合物。TGRs也可能发生在碳水化合物和糖苷配基之间，比如日常食用的食物（如咖啡）中存在的酚类化合物。在本研究中，对咖啡黑素中的糖苷键连接的酚类化合物进行了定量分析，咖啡黑素是烘焙过程中形成的聚合含氮棕色化合物，被定义为美拉德反应的终产物。所呈现的酚类物质中有三分之一是以糖苷键连接的形式存在。此外，对模拟咖啡豆成分的固态混合物进行烘焙后得出结论：蛋白质在TGRs的扩展过程中起调节作用，因此会调节黑素的组成。总体而言，所获得的结果表明，TGRs是酚类物质掺入黑素的主要机制，并且会被氨基通过美拉德反应所抑制。
