Ultrasound driven conformational and physicochemical changes of soy protein hydrolysates
Ultrasound driven conformational and physicochemical changes of soy protein hydrolysates
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超声波驱动大豆蛋白水解物的构象和物理化学变化
DOI：
10.1016/j.ultsonch.2020.105202
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发表时间：
2020-11-01
影响因子：
8.4
通讯作者：
Sui, Xiaonan
中科院分区：
文献类型：
--
作者：
Tian, Ran;Feng, Junran;Sui, Xiaonan
研究了超声波对大豆分离蛋白水解物(SPHs)的构象和理化性质的影响。分别在20min、60min和180min的水解时间下制备SPHs，然后在频率为20 kHz、输出功率为150W和450W的超声作用下处理10min、20min和30min。通过傅立叶变换红外光谱(FTIR)、本征荧光光谱、DPPH自由基清除活性测定和显微镜观察来评价超声处理后SPHs水层的结构性质和抗氧化能力。结果表明，超声波处理显著破坏了蛋白质水解过程中形成的多肽聚集体。超声处理后，蛋白质的溶解度显著增加(最高可达18.33%)，蛋白质中分子量为1 kDa的蛋白质所占比例也显著增加。用DPPH法测定，ASPHs的抗氧化能力也有所提高。对ASPHs的FTIR分析表明，蛋白质的二级结构发生了变化，β-折叠增加，α-螺旋和β-转角减少。此外，荧光光谱的变化表明，随着侧链上色氨酸残基的大量暴露，蛋白质的三级结构发生了转变。扫描电子显微镜(SEM)和原子力显微镜(AFM)对ASPHs形态结构的观察进一步证实了超声波对多肽聚集体的显著破坏作用。综上所述，超声波可以作为一种有效的处理方法来提高蛋白质水解物的溶解度。
The effect of ultrasound on the conformational and physicochemical properties of soy protein isolate hydrolysates (SPHs) was investigated. SPHs were prepared at hydrolysis times of 20 min, 60 min, and 180 min, then treated with ultrasound for 10 min, 20 min, and 30 min at a frequency of 20 kHz and output powers of 150 W and 450 W. The structural properties and antioxidant capacities of the aqueous layer of SPHs (ASPHs) after sonication were evaluated by Fourier-transform infrared spectroscopy (FTIR), intrinsic fluorescence, DPPH radical scavenging activity assays, and microscopy observations. Results obtained showed that ultrasound treatment significantly disrupted the peptide aggregates formed during protein hydrolysis. The protein solubility was significantly increased after sonication (by up to 18.33%), as did the percentage of proteins with MW < 1 kDa in ASPHs. The antioxidant capacity of ASPHs also increased, as measured by DPPH assay. FTIR analysis of ASPHs indicated that the protein secondary structures were different, with an increase in beta-sheet and a decrease in alpha-helix and beta-turn. Furthermore, the changes in fluorescence spectra of ASPHs showed the transition of protein tertiary structure with a greater exposure of Trp residues in the side chains. Scanning electron microscope (SEM) and atomic force microscope (AFM) observations of the morphological structure of ASPHs further confirmed the significant effect of sonication on disrupting peptide aggregates. In conclusion, ultrasound can be used as an efficient treatment to promote the solubility of protein hydrolysates.