Abstract:In this study, egg albumin was used to study the functional properties and structural changes of its relative powder under the optimal spray drying conditions. Taking powder yield rate as index, the optimum process conditions of spray drying were made of the de-sugaring time of 32 h, the feed liquid speed of 466 mL/h, the egg white liquid mass concentration of 29%, the inlet temperature of 140 ℃ and the outlet temperature of 65 ℃. Under this condition, the powder yield rate was 16.17%. The effect of spray drying on the functional properties of egg albumin, such as solubility, emulsifying property, foaming property, foaming stability, moisture content and color difference, were studied, with the vacuum-freeze drying as control. The results showed that no significant difference in solubility, emulsification, foaming ability, foam stability and moisture content was found between the spray-dried protein and the vacuum freeze-dried protein (P>0.05). Moreover, the spray-dried protein had higher brightness, lower redness and yellowness, and maintained good color quality. Fourier transform infrared (FT-IR) analysis showed that the spray-dried protein was red-shifted at the amide I band, resulting in the C═O stretching oscillation of the amide I band. Scanning electron microscopy (SEM) analysis showed that the surface of spray-dried protein was a spherical shape with different sizes, small particles and irregular shape, while the surface of vacuum freeze-dried protein presented a smooth lamellar structure.