Viscoelastic behaviour of β-lactoglobulin gel structures
Viscoelastic behaviour of β-lactoglobulin gel structures
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DOI：
10.1016/s0268-005x(09)80013-1
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发表时间：
1990-06
影响因子：
10.7
通讯作者：
M. Stading;A. Hermansson
中科院分区：
文献类型：
--
作者：
M. Stading;A. Hermansson
本文用动态流变学方法研究了β-乳球蛋白溶于蒸馏水制成的β-乳球蛋白凝胶在pH2.5 -9.0范围内的粘弹性能。在pH 4-6下形成的凝胶是不透明的，并被定义为聚集体或颗粒凝胶;在低于或高于该范围的pH下，凝胶是透明的，并被定义为细链凝胶。聚集体凝胶在凝胶化过程中更应变敏感，并且比细链凝胶更依赖于频率。在12%（w/w）的恒定β-乳球蛋白浓度下，它们还具有比细链凝胶更高的储能模量。凝胶形成的临界浓度是较低的聚集体凝胶比细链凝胶，低至1%的pH范围内4.5-5.5。这是一个非常开放的结构。在中等pH值下，12% β-乳球蛋白凝胶的凝胶化起始温度远低于变性温度，当在1 Hz下测量G ′=G″时，或当可测量的G ′出现时。在较高或较低的pH下情况并非如此，其中凝胶化的开始高于变性温度。凝胶形成过程中的加热速率在0.008和1°C/min之间变化。发现细链凝胶的凝胶化温度随着加热速率的增加而增加。
The viscoelastic properties of β-lactoglobulin gels, made by dissolution of β-lactoglobulin in distilled water, have been investigated by dynamic rheological measurements at pH 2.5–9.0. Gels formed at pH 4–6 were opaque and have been defined as aggregate or particle gels; at pH below or above this range gels were transparent and have been defined as fine-stranded gels. The aggregate gels were more strain sensitive during gelation and more frequency dependent than the fine-stranded gels. They also had a higher storage modulus than the fine-stranded gels at a constant β-lactoglobulin concentration of 12% (w/w). The critical concentration for gel formation was lower for the aggregate gels than for the fine-stranded gels, and as low as 1% in the pH range 4.5–5.5. This indicates a very open structure. The onset of gelation of 12% β-lactoglobulin gels at intermediate pH, when measured asG′=G″at 1 Hz or as the development of a measurableG′ takes place at temperatures far below the temperature of denaturation. This is not the case at higher or lower pH, where the onset of gelation is above the temperature of denaturation. The heating rate during gel formation was varied between 0.008 and 1°C/min. The gelation temperature of the fine-stranded gels was found to increase with an increasing heating rate.