Institut für Lebensmitteltechnologie und Lebensmittelchemie, Fachgruppe Lebensmittelchemie und Analytik, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany; Ministry of High Education and Scientific Research, Street 52, 55509 Baghdad, Iraq.
Institut für Chemie, Max-Volmer-Labor für Biophysikalische Chemie, Technische Universität Berlin, Straße des 17. Juni, 135, 10623 Berlin, Germany.
Food Chem. 2019 May 30;281:106-113. doi: 10.1016/j.foodchem.2018.12.054. Epub 2018 Dec 19.
Melanoidins formed from different carbohydrates, such as d-glucose, d-fructose, and d-xylose, and their typical degradation products, such as hydroxymethylfurfural, furfural, glyoxal, and methylglyoxal, with l-alanine were analyzed with Fourier transform infrared spectroscopy (FTIR). Characteristic infrared bands were identified representing spectral differences between the investigated melanoidin species due to their different molecular compositions. With the help of principal components analysis (PCA) the IR data allowed for a fast discrimination between the different model melanoidins. From this study it is inferred that the intensity and relative absorption wavelength of CO single versus CO double bonds are characteristic features of the investigated melanoidins. Melanoidins formed from carbohydrates exhibit less carbonyl functions in comparison to melanoidins from the degradation products, the situation is opposite for the CO bond. The amount of CO is additionally correlated with a higher absorption at 420 nm indicating that strong colored melanoidins contain more carbonyl functions.
采用傅里叶变换红外光谱（FTIR）分析了不同碳水化合物（如 d-葡萄糖、d-果糖和 d-木糖）及其典型降解产物（如羟甲基糠醛、糠醛、乙二醛和甲基乙二醛）与 l-丙氨酸形成的类黑精。特征红外带的识别代表了由于不同的分子组成而导致的所研究的类黑精种类之间的光谱差异。借助主成分分析（PCA），IR 数据允许快速区分不同的模型类黑精。从这项研究中可以推断，CO 单键与 CO 双键的强度和相对吸收波长是所研究的类黑精的特征。与降解产物形成的类黑精相比，碳水化合物形成的类黑精的羰基功能较少，而 CO 键的情况则相反。CO 的数量还与 420nm 处的更高吸收相关，这表明强烈着色的类黑精含有更多的羰基功能。
