Floury Juliane, Bianchi Tiago, Thévenot Jonathan, Dupont Didier, Jamme Frédéric, Lutton Evelyne, Panouillé Maud, Boué François, Le Feunteun Steven
UMR STLO, Agrocampus Ouest, INRA, 35000 Rennes, France.
IRTA-Food Industries, Monells, Spain.
Food Chem. 2018 Jan 15;239:898-910. doi: 10.1016/j.foodchem.2017.07.023. Epub 2017 Jul 8.
A novel time-lapse synchrotron deep-UV microscopy methodology was developed that made use of the natural tryptophan fluorescence of proteins. It enabled the monitoring in situ of the microstructural changes of protein gels during simulated gastric digestion. Two dairy gels with an identical composition, but differing by the coagulation mode, were submitted to static in vitro gastric digestion. The kinetics of gel particle breakdown were quantified by image analysis and physico-chemical analyses of digesta. The results confirm the tendency of rennet gels, but not acid gels, to form compact protein aggregates under acidic conditions of the stomach. Consequently, the kinetics of proteolysis were much slower for the rennet gel, confirming the hypothesis of a reduced pepsin accessibility to its substrate. The particle shapes remained unchanged and the disintegration kinetics followed an exponential trend, suggesting that erosion was the predominant mechanism of the enzymatic breakdown of dairy gels in these experimental conditions.
开发了一种新型的延时同步加速器深紫外显微镜方法，该方法利用了蛋白质的天然色氨酸荧光。它能够在模拟胃消化过程中原位监测蛋白质凝胶的微观结构变化。将两种组成相同但凝固方式不同的乳凝胶进行静态体外胃消化。通过对消化物的图像分析和物理化学分析来量化凝胶颗粒分解的动力学。结果证实了在胃的酸性条件下，凝乳酶凝胶而非酸凝胶形成紧密蛋白质聚集体的趋势。因此，凝乳酶凝胶的蛋白水解动力学要慢得多，这证实了胃蛋白酶对其底物的可及性降低的假设。颗粒形状保持不变，崩解动力学呈指数趋势，这表明在这些实验条件下，侵蚀是乳凝胶酶促分解的主要机制。
