逆流聚能式超声预处理对谷朊蛋白酶解及其结构和热特性的影响

Effects of CFU Pretreatment on Enzymatic Preparations of ACE-inhibitory Peptides from Wheat Gluten and Its Structural Characterization

采取逆流聚能式超声波预处理技术提高谷朊蛋白酶解制备ACE抑制肽的效率。以谷朊蛋白酶解产物的ACE抑制率为指标,通过Box-Behnken响应面试验设计,建立逆流超声预处理谷朊蛋白的数学模型,优化技术参数。利用原子力显微镜、紫外光谱、荧光光谱、差示量热扫描仪对超声预处理后蛋白结构性质进行分析。结果表明,在超声波频率20 k Hz、功率446 W条件下,逆流超声预处理谷朊蛋白制备ACE抑制肽模型的最优条件为:脉冲超声工作时间4 s、间歇时间3 s、料液初始温度30℃、预处理时间30 min。在最优条件下,ACE抑制率为77.235%,IC50值为0.41 mg/m L,分别比未超声预处理的对照组提高了29.8%,降低了36.92%。结构及热特性分析表明,超声预处理改变了谷朊蛋白的微观形貌,使其表面粗糙度变大;蛋白分子发生了伸展,高级结构改变;热转变温度及热焓值下降。形貌、结构及热特性的变化表明超声波预处理使谷朊蛋白有利于酶解反应的进行。

Uhrasonic technology has important biological significance and potential value on the preparation of ACE inhibitory peptides and improves its biological activity. In this study, response surface methodology （RSM） was employed to optimize the preparation of ACE-inhibitory peptides from wheat gluten based on counter flow ultrasound （CFU） pretreatment. Meanwhile, the structural characterization of wheat gluten was also analyzed by AFM, uhravielet spectrum,fluorescence spectrum and differential scanning calorimetry （DSC）. The result showed that the optimal CFU pretreatment conditions were single ultrasonic treatment for 4 s followed by a 3 s interval, the initial temperature was at 30 ℃, and 30 rain of total pretreatment time（The frequency of the ultrasonic was 20 kHz, the power was 446 W）. Under the optimal pretreatment conditions, the ACE inhibitory activity was 77,235% and increased by 29.8%, the ICs0 value was 0.41 mg/ mL and decreased by 36.92%. Structural analysis showed that the CFU pretreatment changed the mierostructure of gluten proteins, and result in the surface roughness becomes larger; Molecular structure of the protein was extended, the ultraviolet spectrum and fluorescence spectrum was were changed; Thermal denaturation temperature and the enthalpy of wheat gluten with CFU pretreatment were declined.