FTIR分析脉冲电场和热处理后的大豆分离蛋白结构变化  

Effects of Pulsed Electric Fields and Heat Treatments on SPI Structure Analyzed by FTIR

作　　者：刘燕燕[1] 曾新安[1] 陈晓东 

机构地区：[1]华南理工大学轻工与食品学院,广东广州510640 [2]Department of Chemical Engineering, Faculty of Engineering, Monash University, Clayton, VIC 3800, Australia

出　　处：《光谱学与光谱分析》2010年第9期2340-2344,共5页Spectroscopy and Spectral Analysis

基　　金：广东省国际合作重点项目(2009B050400003);广东省自然科学基金项目(9151008901000159)资助

摘　　要：采用自行研制的脉冲电场设备,利用傅里叶变换红外光谱(FTIR)比较研究了脉冲电场(PEF)和热处理对大豆分离蛋白(SPI)分子结构的影响。结果表明:50 kV.cm-1的脉冲场强处理引起SPI分子内和分子间氢键增强,分子中C—O—O糖苷键伸缩振动和P O,P—O—C伸缩振动增强,且其增加值与PEF处理时间呈正相关。研究发现较短时间(1 600μs)PEF处理导致了SPI分子结构中α-螺旋和β-折叠分别减少了5.9%和0.7%,β-转角和侧链结构分别增加了7.5%和9.6%;处理时间延长至2 400μs,其α-螺旋和β-折叠减少量增至6.0%和5.6%。对比而言,热处理对SPI分子结构中C—O—O糖苷键伸缩振动和P O,P—O—C伸缩振动的影响程度较大,而对蛋白质二级结构影响程度较小:90℃热处理30 min,α-螺旋和β-折叠分别减小5.1%和6.6%,β-转角结构增加19.1%。由此可以认为PEF和热处理对SPI的影响机理是不一样的。The effects of pulsed electric field（PEF） under 50 kV·cm-1 as well as heat treatments on the secondary structure of soy protein isolate（SPI） were investigated by Fourier transform infrared（FTIR） method in the present paper.A set of self-designed and made PEF equipment was used.It was demonstrated from the FTIR spectra that the PEF treatment under 50 kV·cm-1 had induced the increase in hydrogen bonds amidst in the intermolecule and intramolecule of SPI,and the increase in C—O—O bonds stretch vibration and the PO or P—O—C stretch vibration,which is positive relative to the increase in the time of PEF treatment.It was shown that after PEF treatment,the ratio of α-helix and β-sheet structure in SPI was decreased by 5.9% and 0.7%,respectively.On the other hand,the ratio of β-turn and side chain vibration structure was obviously increased by 7.5% and 9.6% at the treatment time of 1 600 μs,respectively.Comparatively the effect of heat treatments with 90 ℃ for 30 min on the C—O—O bonds stretch vibration and the PO or P—O—C stretch vibration is more evident,but the effect of which on the secondary structure of SPI is less.So it is concluded that the effect mechanism of PEF and HT on SPI structure is significantly different.

关 键 词：高强脉冲电场 热处理 大豆分离蛋白 红外光谱 蛋白质二级结构 

分 类 号：TS214.2[轻工技术与工程—粮食、油脂及植物蛋白工程]