Characterization of commercial and experimental sodium caseinates by multiangle laser light scattering and size-exclusion chromatography.
Characterization of commercial and experimental sodium caseinates by multiangle laser light scattering and size-exclusion chromatography.
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DOI：
10.1021/jf990769z
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发表时间：
2000-04
影响因子：
6.1
通讯作者：
J. Lucey;M. Srinivasan;H. Singh;P. Munro
中科院分区：
文献类型：
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作者：
J. Lucey;M. Srinivasan;H. Singh;P. Munro
一系列酪蛋白酸钠样品的特点是由多角度激光散射（MALLS）系统或使用MALLS作为在线检测器与尺寸排阻色谱（SEC）。单独使用MALLS系统分析酪蛋白酸钠溶液，得到1200-4700 kDa范围内的重均摩尔质量（M（w））值和约50 - 120 nm范围内的z-平均均方根半径（R（g））值。当这些溶液在90000 g下超浓缩1小时时，形成浑浊的顶层;小心地除去下层液并通过SEC-MALLS分析。发现M（w）值在约30-575 kDa的范围内，R（g）值在约22 - 49 nm的范围内。在SEC期间，MALLS系统检测到一些非常大尺寸的材料，其在空隙体积附近洗脱;该材料几乎不能被浓度检测器检测到，即，紫外线（UV）和差示折射率（DRI）。来自这种非常大尺寸的材料的光散射（LS）信号的强度在下清液中大大降低。酪蛋白酸钠样品的SEC显示两个主峰，M（w）分别为约420-750 kDa和39-69 kDa。蛋白质分子的R（g）值非常大，初步计算表明酪蛋白酸盐分子的形状可能是高度细长的。
A range of sodium caseinate samples were characterized by a multiangle laser light scattering (MALLS) system or by the use of MALLS as an on-line detector with size-exclusion chromatography (SEC). Sodium caseinate solutions, analyzed using a MALLS system alone, gave weight-average molar mass (M(w)) values in the range 1200-4700 kDa and z-average root-mean-square radius (R(g)) values ranged from approximately 50 to 120 nm. When these solutions were ultracentrifuged at 90000g for 1 h, a cloudy top layer was formed; the subnatant was carefully removed and analyzed by SEC-MALLS. The M(w) values were found to be in the range approximately 30-575 kDa, and R(g) values ranged from approximately 22 to 49 nm. During SEC, the MALLS system detected some very large-sized material that eluted close to the void volume; this material was hardly detected by the concentration detectors, i.e., ultra-violet (UV) and differential refractive index (DRI). The intensity of the light scattering (LS) signal from this very large sized material was greatly reduced in the subnatant. SEC of sodium caseinate samples revealed two main peaks with M(w) of approximately 420-750 kDa and 39-69 kDa, respectively. The R(g) values were very large for a protein molecule, and initial calculations suggested that the shape of caseinate molecules was likely to be highly elongated.