微波功率对蛋清蛋白粉乳化特性的影响

Effect of microwave power on emulsifying properties of egg white protein powder

【目的】研究微波真空冷冻干燥不同功率(100~500 W)对蛋清蛋白粉乳化特性的影响,为生产高品质蛋清蛋白粉提供参考。【方法】通过乳化性、Zeta电位、粒径、浊度以及傅里叶变换红外光谱、内源荧光光谱、扫描电镜、光学显微镜探究微波真空冷冻干燥不同功率对蛋清蛋白粉乳化特性和结构的影响。【结果】乳化性分析表明:随着微波功率的增加,蛋清蛋白粉乳液的乳化性和Zeta电位绝对值先增加后减小,平均粒径和浊度先降低后增加(P<0.05),其中微波功率为300 W时,蛋清蛋白粉乳液的乳化活性指数和乳化稳定性指数均达到最大值,分别为62.35 m^(2)/g和33.53 min;平均粒径最小,为1203.67 nm,蛋清蛋白粉乳液粒度分布呈现单峰曲线,蛋白质更均匀地分布在乳液中。结构分析表明:随着微波功率的增加,蛋清蛋白粉二级结构中α-螺旋相对含量降低,β-转角相对含量先增加后降低;最大荧光发射强度降低,最大发射波长发生蓝移,蛋清蛋白粉微观结构展开程度先增加后减小,乳液液滴直径先减小后增大;其中微波功率为300 W时,蛋清蛋白粉乳液液滴直径最小且分布最均匀,蛋清蛋白表面展开程度最大,质地最疏松。【结论】微波真空冷冻干燥功率对蛋清蛋白粉乳化特性的影响显著,采用300 W微波功率处理蛋清蛋白,可显著改善其乳化特性。

【Objective】This study investigated the effect of microwave vacuum freeze drying with different power(100-500 W)on emulsification characteristics of egg white protein powder to provide refe-rence for producing high-quality egg white protein powder.【Method】The characteristics of emulsification,Zeta potential,particle size and turbidity were analyzed and Fourier transform infrared spectroscopy,endo-genous fluorescence spectroscopy,scanning electron microscopy and optical microscopy were used to investigate the effects of different microwave power conditions on the emulsification properties and structure of egg white protein powder.【Result】The emulsification analysis showed that with the increase of microwave power,emulsification property of emulsion and absolute value of Zeta potential first increased and then decreased,while the average particle size and turbidity first decreased and then increased(P<0.05).When the microwave power was 300 W,the emulsification activity and emulsification stability reached the maximum values of 62.35 m^(2)/g and 33.53 min,and the average particle size reached the smallest value of 1203.67 nm.The particle size distribution of egg white protein powder emulsion showed a unimodal distribution,and protein was more evenly distributed in the emulsion.Structural analysis showed that the relative content ofα-helix in the secondary structure of egg white protein powder decreased with the increase of microwave power,the relative content ofβ-turn angle first increased and then decreased,while the maximum fluorescence emission intensity decreased.The maximum emission wavelength shifted to blue,the degree of microstructure expansion of egg white protein powder first increased and then decreased,and the droplet diameter of emulsion first decreased and then increased.When the microwave power was 300 W,the emulsion droplet diameter was the smallest and the distribution was the most uniform.The surface spread of egg white protein was the largest and the texture was the loosest.【Conclusion】The power of microwave vacuum freeze drying had significant effects on emulsifying properties of egg white protein powder and the optimal microwave power was 300 W.