超声波加工对蛋清蛋白质结构和凝胶特性的影响

为研究超声波加工对蛋清蛋白质结构和凝胶特性的影响,以蛋清为原料进行超声处理,通过对超声前后蛋清蛋白质的空间结构、分子分布和流变学性能进行分析,同时对超声后蛋清凝胶的保水性、质构特性等进行测定。结果表明,在200 W和400 W的超声处理下,蛋清蛋白发生了折叠和聚集,也有小部分发生了降解。在600 W的超声处理下,蛋清蛋白发生了部分降解,同时还有小部分蛋白发生了聚集。因此,超声使部分蛋白质分子粒径变大,部分蛋白质分子粒径变小,整体分子粒径分布变窄。200 W、10 min和600 W、30 min的超声处理下,蛋清溶液偏向于液体的流变性。在200、400 W和600 W 3种功率的超声处理下,蛋清凝胶的保水性增强。200 W和400 W的超声处理有利于增强蛋清的凝胶强度,使凝胶更加坚固和致密。600 W、30 min的超声处理会使蛋清的凝胶强度显著降低,从而使凝胶的稳定性降低。研究结果可为改善蛋清的凝胶性能提供一定的参考。

Effect of Ultrasonic Processing on Protein Structure and Gel Properties of Egg White

In order to explore the effect of ultrasound on the structure and gel properties of egg white proteins, the spatial structure, molecular distribution and rheological properties of egg white proteins before and after ultrasonic treatment were analyzed, and the water retention and texture properties of egg white gel were determined. Results showed that at ultrasound powers of 200 and 400 W, the structure of some egg white proteins were folded and aggregated; meanwhile, only a small fraction were degraded. On the other hand, at 600 W ultrasound power, egg white proteins were partially degraded, and only a small fraction were aggregated. Therefore, ultrasound could increased the particle sizes of some proteins, and decreased the particle sizes of others, narrowing the overall particle size distribution. Egg white treated at 200 W for 10 min or at 600 W for 30 min had similar rheological properties to those of a liquid. At all three powers, water-holding capacity of egg white gel was increased. Ultrasonic treatment at 200 or 400 W enhanced gel strength, making the gel more firm and compacted. On the contrary, ultrasonic treatment at 600 W for 30 min significantly decreased gel strength and consequently decreased gel stability. These results may provide a basis for improving gel properties of egg white proteins.