高场强超声对蛋清液起泡特性的影响

为改善蛋清液的起泡性,采用不同超声功率(120,240 W)和超声时间(1,5,10,20,30 min)的高场强超声(20 kHz)对蛋清蛋白进行改性。结果表明,在功率120 W下超声处理20 min,蛋清蛋白的起泡性最佳(266.7%),是未处理蛋清的6.9倍。超声处理显著降低了蛋清液的表观黏度、表面张力和粒径大小(P <0.05),使蛋白质分子更易吸附到气-液界面进行展开和重排。Zeta电位测定结果表明,相比未处理蛋清,在功率120 W下超声20 min,蛋白质表面的负电荷明显减少(由-14.47 mV减至-8.16 mV,P <0.05)。流变结果显示:蛋清蛋白在界面处的蛋白膜一直以弹性为主导,表现出黏弹性固体性质。超声处理没有改变其流体状态,始终呈假塑性流体状态。

Effects of High Intensity Ultrasound on Foaming Characteristics of Egg White Liquid

The foaming property of egg white protein is widely used in bakery food.In order to improve the foaming property of egg white liquid,high field intensity ultrasound (20 kHz) with different ultrasonic power (120,240 W) and ultrasonic time (1,5,10,20,30 min) was set to modify the egg white protein.It was found that the foaming ability of egg white was the best (266.7%) when treated with 120 W ultrasound for 20 min,which was 6.9 times of that of untreated egg white.Ultrasonic treatment significantly reduced the viscosity,surface tension and particle size of the egg white (P < 0.05),which made the protein molecules more easily adsorbed to the gas-liquid interface for unfolding and rearrangement.The results of zeta potential indicated that the negative charge on the protein surface was significantly decreased at 120 W for 20 min compared with untreated egg white (reduced from -14.47 to -8.16 mV,P < 0.05).The rheology results showed that the protein membrane of egg white at the interface was always dominated by elasticity,showing the properties of viscoelastic solid,and the ultrasonic treatment didn''t change its fluid state,showing a pseudoplastic fluid state all the time.