Effects of Acidification with and without Rennet on a Concentrated Casein System: A Kinetic NMR Probe Diffusion Study
Effects of Acidification with and without Rennet on a Concentrated Casein System: A Kinetic NMR Probe Diffusion Study
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使用和不使用凝乳酶的酸化对浓缩酪蛋白系统的影响：动力学 NMR 探针扩散研究
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
F. Mariette
中科院分区：
文献类型：
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作者：
S. Feunteun;F. Mariette
在单独酸化和凝乳酶联合作用诱导的浓缩酪蛋白悬浮液的整个凝固过程中，通过脉冲场梯度 (PFG)-NMR 测量了 620 和 96-750 g/mol 聚乙二醇 (PEG) 的自扩散系数。还研究了酸化过程中水分子的扩散。在所有实验中，所研究的分子的扩散系数都是非线性修改的，其演化变化的精确时刻对应于两个凝固过程的关键阶段。这些变化与流变测量揭示的溶胶-凝胶转变并不直接相关，而是由样品中其他类型的结构变化引起，无论其粘弹性状态（溶液或凝胶）如何。大PEG的扩散对胶凝前后酪蛋白颗粒和构成网络的酪蛋白聚集体的尺寸变化非常敏感。相比之下，扩散...
The self-diffusion coefficients of 620 and 96 750 g/mol poly(ethylene glycol) (PEG) were measured by pulsed field gradient (PFG)-NMR throughout the coagulation processes of a concentrated casein suspension induced by acidification alone and with the concomitant action of chymosin. The diffusion of water molecules was also investigated during the acidification process. In all experiments, the diffusion coefficient of the molecule studied was modified nonlinearly, and the precise moments at which its evolution changed corresponded to key stages of both coagulation processes. These variations were not directly related to sol−gel transitions as revealed by rheological measurements but were caused by other types of structural changes in the sample whatever its viscoelastic state (solution or gel). The diffusion of the large PEG was very sensitive to variations in the size of the casein particles and the casein aggregates constituting the network before and after gelation, respectively. In contrast, the diffusi...