Department of Food Science, University of Minnesota, 1334 Eckles Avenue St. Paul, MN 55108, United States.
Food Chem. 2013 Aug 15;139(1-4):313-9. doi: 10.1016/j.foodchem.2012.12.050. Epub 2013 Jan 16.
Maillard-induced glycosylation of whey protein improves solubility and thermal stability over a wide pH range. However, the relationship between structural changes and functional enhancement upon glycosylation is not well-characterized. Therefore, our objective was to characterise these structural changes and determine the protein conformation at various pH and thermal treatments, using surface-enhanced Raman-spectroscopy. The spectra of glycosylated protein revealed a new peak at 983 cm(-1) that can be used as a Raman marker for the early stage glycosylation. Upon glycosylation, structural variations were significant at the disulfide, hydrophobic, amide III, amide II, and amide I regions. Ionisation of carboxyl groups at all tested pH values, and increased β-sheet configuration were also observed. The noted structural modifications imparted molecular rigidity and a consequent resistance to denaturation upon thermal treatment over a wide pH range. These findings can be used to explain various functional enhancements of whey protein upon glycosylation.
美拉德诱导的乳清蛋白糖化作用可提高蛋白质在宽 pH 范围内的溶解度和热稳定性。然而，糖化作用导致的结构变化与功能增强之间的关系尚未得到很好的阐明。因此，本研究旨在利用表面增强拉曼光谱对这些结构变化进行表征，并确定不同 pH 值和热处理条件下的蛋白质构象。糖基化蛋白的光谱在 983 cm(-1)处出现新的峰，可作为早期糖基化的拉曼标记物。糖基化后，二硫键、疏水、酰胺 III、酰胺 II 和酰胺 I 区域的结构变化显著。在所有测试的 pH 值下，羧基离子化和β-折叠结构的增加也被观察到。这些结构修饰赋予了分子刚性，从而在宽 pH 范围内的热处理过程中提高了蛋白质的抗变性能力。这些发现可以用来解释乳清蛋白糖化作用带来的各种功能增强。
