Heat and/or ultrasound pretreatments motivated enzymolysis of corn gluten meal: Hydrolysis kinetics and protein structure
Heat and/or ultrasound pretreatments motivated enzymolysis of corn gluten meal: Hydrolysis kinetics and protein structure
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DOI：
10.1016/j.lwt.2016.06.048
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发表时间：
2017-04-01
影响因子：
6
通讯作者：
Otu, Phyllis Naa Yarley
中科院分区：
文献类型：
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作者：
Zhou, Cunshan;Hu, Jiali;Otu, Phyllis Naa Yarley
研究了热（HP）、超声波（UP）、热/超声波（HPUP）和超声波/热（UPHP）预处理对玉米蛋白粉（CGM）蛋白酶促水解的影响。对CGM蛋白的酶促动力学、分子构象和微观结构进行了研究。酶解反应速率随底物浓度的增加而增加，80 g/L时酶解反应速率最高。对CGM评分的改善效果以HPUP最好（KM值降低了11.56%），其次是UPHP（KM值降低了9.97%）。荧光光谱和傅立叶变换红外光谱（FTIR）表明，CGM预处理诱导分子解折叠，暴露的疏水基团。HPUP和UPHP预处理均使α-螺旋含量降低12.2%，无规卷曲含量分别增加2.23%和2.60%。扫描电子显微镜和原子力显微镜显示HPUP和UPHP改变了蛋白质颗粒的表面形貌和分布，提高了蛋白质的降解速率。超声波与热预处理结合可控热处理是一种有效的球形蛋白功能化改性方法。(C)2016爱思唯尔有限公司版权所有。
The purpose of this study was to investigate the effect of pretreatments of heat (HP), ultrasound (UP), and combinations of heat/ultrasound (HPUP) and ultrasound/heat (UPHP) on protamex-catalyzed enzymolysis of corn gluten meal (CGM). Enzymolysis kinetics, molecular conformation and microstructure of CGM protein were monitored. Enzymolysis reaction rate increased with increasing substrate concentration and 80 g/L resulted in the highest hydrolysis reaction rate. The best improvement in CGM enzymolysis was obtained by HPUP (KM value decreased by 11.56%) and then followed by UPHP (KM value decreased by 9.97%). Fluorescence spectra and fourier transform infrared (FTIR) spectra indicated that the CGM pretreatments induced molecular unfolding, exposing the hydrophobic groups. HPUP and UPHP pretreatments both decreased the a-helix content by 12.2% and increased the random coil content by 2.23 and 2.60%, respectively. Scanning electron microscopy and atomic force microscopy showed that HPUP and UPHP changed surface topography and distribution of protein particles, enhancing the rate of enzymolysis. In conclusion, combined ultrasound and heat pretreatment and controlled enzymolysis could be an effective method for the functionality modification of globular proteins. (C) 2016 Elsevier Ltd. All rights reserved.