不同打发状态蛋清泡沫及其凝胶特性的比较

蛋清具有良好的起泡性和凝胶性，其在充气食品中具有难以取代的地位。为研究不同状态蛋清泡沫凝胶的理化性质，该文在室温条件下以恒定搅拌速率（980 r/min）制备了不同打发状态（打发时间为0、50、70和90 s）的蛋清泡沫，并测定了蛋清泡沫的理化特性。随后将不同打发时间的蛋清泡沫加热固化，制备了蛋清泡沫凝胶，通过显微观察、色度、质构和流变分析考察了蛋清泡沫凝胶的特性。实验结果表明，在恒定的搅拌速率下蛋清泡沫的气泡状态会随打发时间的变化而变化。适当延长打发时间，有利于形成比重较低的（0.16～0.17）、具有高起泡性和泡沫稳定性的固态泡沫。打发70 s的蛋清泡沫（蛋清泡沫呈小弯钩状，比重为0.165）稳定性最佳，且经加热固化后，该蛋清泡沫凝胶的亮度（L*=90.28）显著升高，硬度（27.69 g）和弹性（0.78 mm）显著降低（P<0.05），凝胶性质优良。结果揭示了蛋清泡沫的流变学性质能显著影响蛋清泡沫及其凝胶的性能，为蛋清泡沫在充气食品中的应用提供了理论参考。

Comparison of Egg White Foams in Different Whipping States and Their Gel Properties

Egg white has good foaming and gelling properties, thus plays an irreplaceable role in aerated foods. In order to study the physico-chemical properties of egg white foam gels in different states, egg white foams in different whipping states (whipping time: 0, 50, 70 or 90 s) were prepared at room temperature and a constant stirring rate (980 r/min). The physicochemical properties of the egg white foams were determined. Then, the egg white foams with different whipping times were heated for solidification to prepare egg white foam gels. The properties of the egg white foam gels were investigated through microscopic observation, color measurements, texture analysis and rheological analysis. The experimental results showed that at a constant stirring rate, the bubble state of the egg white foam changed with the whipping time. Prolonging the whipping time appropriately could benefit the formation of solid foam with low specific gravity (0.16~0.17), high foaming ability and foam stability. The egg white foam after being whipped for 70 s (foam in small hook-like shape, with a specific gravity of 0.165) had the highest stability. After being heated for solidification, the lightness of such an egg white foam gel (L*=90.28) increased significantly, whilst the hardness (27.69 g) and elasticity (0.78 mm) decreased significantly (P<0.05), exhibiting excellent gel properties. The results revealed that the rheological properties of egg white foam influenced significantly the properties of egg white foam and its gel, which provides a theoretical reference for the application of egg white foam in aerated foods.