School of Applied Sciences, RMIT University, City Campus, Melbourne, Vic. 3001, Australia.
School of Applied Sciences, RMIT University, City Campus, Melbourne, Vic. 3001, Australia.
Food Chem. 2014 May 1;150:469-76. doi: 10.1016/j.foodchem.2013.11.029. Epub 2013 Nov 16.
The present study shows that application of high hydrostatic pressure of 600MPa for 15min at ambient temperature on condensed bovine serum albumin systems (BSA) with up to 80% w/w solids content has a limited effect on the conformational structure of the protein, as compared to thermal treatment. This was demonstrated throughout the experimental concentration range using small-deformation dynamic oscillation, differential scanning calorimetry and infrared spectroscopy. BSA possesses seventeen disulfide linkages per molecule, which constitutes a stable arrangement with high energy requirements for substantial structure alteration. Upon cooling, pressurised materials undergo vitrification and networks exhibit comparative mechanical strength to that of thermally treated counterparts. The mechanical manifestation of the glass transition region and glassy state for atmospheric and pressurised samples was examined by the method of reduced variables and the combined framework of WLF/free volume theory producing disparate predictions of the glass transition temperature for the two types of polymeric network.
本研究表明，与热处理相比，在环境温度下将 600MPa 的高压应用于高达 80%w/w 固体含量的浓缩牛血清白蛋白（BSA）体系 15 分钟，对蛋白质的构象结构只有有限的影响。在整个实验浓度范围内，使用小变形动态振荡、差示扫描量热法和红外光谱法进行了证明。BSA 每个分子有十七个二硫键，这构成了一个稳定的排列，需要大量的结构改变来达到高能量。冷却时，加压材料经历玻璃化转变，网络表现出与热处理对应物相当的机械强度。通过降维法和 WLF/自由体积理论的组合框架，对常压和加压样品的玻璃化转变区和玻璃态的力学表现进行了研究，这两种类型的聚合物网络对玻璃化转变温度有不同的预测。
