采用自行研制的高强脉冲电场设备, 利用拉曼光谱分析脉冲电场对大豆分离蛋白微观结构的影响. 结果表明, 在50 kV·cm-1的高强脉冲场强下, PEF诱导2 886 cm-1附近峰明显消失, 脂肪族侧链C—H伸缩振动微环境极性和色氨酸残基微环境极性不断增强; 诱使C—H平面弯曲振动、 C—N伸缩振动, 以及天冬氨酸和谷氨酸中的CO伸缩振动减弱; 诱导酰胺键CO伸缩振动和N—H摇摆振动增强. 同时发现酪氨酸被包埋程度随着脉冲时间的延长而先增加后减小, 在脉冲处理时间为1 600 μs 时, 酪氨酸包埋程度最大.

The effect of pulsed electric field on molecular structure of soy protein isolate (SPI) was investigated by Raman spectroscopy method. The applied pulsed electric field was up to 50 kV·cm-1 with pulse width 40 μs. It was demonstrated from the Raman spectra that the PEF treatment under 50 kV·cm-1 had induced disappearance significantly of peak near 2 886 cm-1 bond. It was also explored that with the increase in treatment time, the polarity of microenvironment of aliphatic amino acid residues and the exposure of tryptophan residues from a buried hydrophobic microenvironment were increased. On the other hand, the interaction of serine acid residues, the C—H plane bend vibration, C—N stretch vibration, and the CO stretch vibration of aspartic acid and glutamic acid were decreased. The embeding or participation of the tyrosine phenolic groups as hydrogen bond donors was firstly increased with the treatment time (less than 1 600 μs), and afterwards decreased (from 1 600 to 3 200 μs).