INFLUENCE OF PROTEIN CHARGE ON THERMAL PROPERTIES AS WELL AS MICROSTRUCTURE AND RHEOLOGY OF HEAT INDUCED NETWORKS FOR OVALBUMIN AND VICILIN
INFLUENCE OF PROTEIN CHARGE ON THERMAL PROPERTIES AS WELL AS MICROSTRUCTURE AND RHEOLOGY OF HEAT INDUCED NETWORKS FOR OVALBUMIN AND VICILIN
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蛋白质电荷对卵清蛋白和豌豆蛋白的热性质以及热诱导网络的微观结构和流变学的影响
DOI：
10.1111/j.1745-4603.1990.tb00481.x
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发表时间：
1990
影响因子：
3.2
通讯作者：
M. Ismond
中科院分区：
文献类型：
--
作者：
S. Arntfield;E. Murray;M. Ismond
卵清蛋白和豌豆球蛋白的储能模量（G′）和损耗模量（G″）均表现出对pH的双峰响应;在等电点（IEP）附近和pH极值处获得较低的值。在IEP附近，蛋白质网络具有高的tan δ（G″/G′）值，并且具有高度聚集的特征。在远离IEP的pH值下，微观结构表现为交联良好的网络，具有相应的较低的tan δ值。在大多数情况下，（除了在酸性条件下的卵清蛋白）这种趋势在极端pH值下不会逆转。包括十二烷基硫酸钠（SDS）在pH 8.5的影响类似于增加pH值。对于这两种蛋白质，在高SDS浓度的网络恶化与蛋白质展开和增加蛋白质溶剂相互作用。对于具有低tan δ值的网络（例如，在碱性条件下的卵清蛋白），最终网络中的G模量受到初始冷却阶段期间的变化的影响，而对于聚集产物和大多数豌豆球蛋白网络，最终冷却阶段期间G模量的变化是显著的。静电相互作用的贡献以及交联网络从豌豆球蛋白和卵清蛋白是作为一个排斥力的平衡所需的网络形成。对于豌豆球蛋白，静电相互作用也似乎是一种吸引力，即使在合理的网络形成的条件下。这可以解释两种蛋白质的网络质量的差异。
The storage modulus (G′) and loss modulus (G″) for both ovalbumin and vicilin exhibited bimodal responses with respect to pH; lower values were obtained around the isoelectric points (IEP) and at pH extremes. Around the IEP, protein networks were characterized as highly aggregated with high tan δ (G″/G′) values. At pH values away from the IEP, the microstructure appeared as well crosslinked networks with corresponding lower tan δ values. In most cases, (except ovalbumin in acid conditions) this trend was not reversed at pH extremes. Inclusion of sodium dodecylsulfate (SDS) at pH 8.5 had an effect similar to increasing pH. For both proteins, network deterioration at high SDS concentrations was associated with protein unfolding and increased protein solvent interactions. For networks with low tan δ values (e.g. ovalbumin in alkaline conditions) the G moduli in the final network were influenced by changes during the initial cooling phase, whereas for aggregated products and most vicilin networks, changes in the G moduli during the final cooling phase were prominent. The contribution of electrostatic interactions to well crosslinked networks from both vicilin and ovalbumin was as a repulsive force in the balance required for network formation. For vicilin, electrostatic interactions also appeared to serve as an attractive force even under conditions of reasonable network formation. This may account for the difference in network quality for the two proteins.