Probe mobility in native phosphocaseinate suspensions and in a concentrated rennet gel: effects of probe flexibility and size.
Probe mobility in native phosphocaseinate suspensions and in a concentrated rennet gel: effects of probe flexibility and size.
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天然磷酸酪蛋白酸盐悬浮液和浓缩凝乳酶凝胶中的探针迁移率：探针灵活性和尺寸的影响。
DOI：
10.1021/jf304949c
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发表时间：
2013
影响因子：
6.1
通讯作者：
F. Mariette
中科院分区：
文献类型：
--
作者：
S. Salami;C. Rondeau;J. V. van Duynhoven;F. Mariette
脉冲场梯度核磁共振和质子核磁共振弛豫法被用来研究自扩散系数和分子动力学的线性（PEG）和球形探针（树枝状聚合物）在本地磷酸酪蛋白悬浮液和浓缩凝乳酶凝胶。结果表明，扩散分子的大小和形状以及基体形貌都影响扩散和弛豫速率。在悬浮液中，平移和旋转扩散随着酪蛋白浓度的增加而减少，这是由于运动自由度的限制增加。然而，旋转扩散比平移扩散受到的阻碍要小。凝固后，平移扩散增加，但旋转扩散减少。不同尺寸的探针的T_（max）弛豫时间的分析将由几个单体单元形成的游离短链弛豫与（i）附接至长聚合物链的质子的弛豫和（ii）附接至刚性树枝状聚合物核心的短链弛豫区分开。
Pulsed field gradient nuclear magnetic resonance and proton nuclear magnetic resonance relaxometry were used to study the self-diffusion coefficients and molecular dynamics of linear (PEGs) and spherical probes (dendrimers) in native phosphocaseinate suspensions and in a concentrated rennet gel. It was shown that both the size and the shape of the diffusing molecules and the matrix topography affected the diffusion and relaxation rates. In suspensions, both translational and rotational diffusion decreased with increasing casein concentrations due to increased restriction in the freedom of motion. Rotational diffusion was, however, less hindered than translational diffusion. After coagulation, translational diffusion increased but rotational diffusion decreased. Analysis of the T₂ relaxation times obtained for probes of different sizes distinguished the free short-chain relaxation formed from a few monomeric units from (i) the relaxation of protons attached to long polymer chains and (ii) the short-chain relaxation attached to a rigid dendrimer core.