乳化性能是磷脂酶A2改性蛋黄粉的重要指标。 将磷脂酶A2改性蛋黄液分别在150, 170及190 ℃条件下喷雾干燥制成蛋黄粉, 运用FTIR技术并结合去卷积、 二阶导数、 曲线拟合方法对蛋白质二级结构进行分析。 结果表明, 随喷雾干燥温度的升高, 蛋黄粉的乳化性能及α-螺旋含量均呈现先升高后下降的趋势, 蛋黄粉乳化液的热稳定性不受喷雾干燥温度的影响, 但二级结构会呈现出从α-螺旋向β-折叠转变的趋势, 而代表蛋白质分子内部紧密程度的β+α结构总含量相对稳定。

Spray drying is an important processing of producing modificatied yolk powder (MEYP). To investigate the correlation between the secondary structure and emulsifying property of MEYP made at different spray-drying-temperatures, Fourier transform infrared spectroscopy (FTIR) was applied in the present study. The result indicated that emulsifiability and the percentage of α-helix were both significantly increased firstly and then remarkably decreased with rising of spray-drying-temperature, and the emulsifying property of MEYP was relative to the percentage of α-helix. After heat-treating, the percentage of α-helix was significantly decreased and the percentage of β-sheet was remarkably increased, however, the total percentage of the two structures was maintained. The stable total percentage of α-helix and β-sheet would be a good explanation for the great heat stability of emulsion presented in the MEYP made at different spray-drying temperature.