Zhang Sitian, Zhang Mingdi, Xing Jie, Lin Songyi
College of Food Science and Technology, Jilin University, Changchun, P. R. China.
National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, P. R. China.
J Food Biochem. 2019 Mar;43(3):e12714. doi: 10.1111/jfbc.12714. Epub 2018 Dec 9.
The aim of this study was to investigate the possible mechanism for increasing the antioxidant activity on peptide Glutamine-Tryptophan-Phenylalanine-Histidine (QWFH) from pine nut (Pinus koraiensis) protein by a pulsed electric field (PEF). The antioxidant capacity of PEF-treated QWFH increased significantly (p < 0.05) through 1,1-diphenyl-2-pycryl-hydrazyl radical scavenging and oxygen radical absorbance capacity assays. A series of mechanism exploration methods, including reversed-phase high-performance liquid chromatography, ultraviolet absorption spectroscopy, intrinsic fluorescence spectra, circular dichroism spectroscopy, and 1D and 2D nuclear magnetic resonance spectroscopies, were applied. QWFH chain was not cleaved by the PEF treatment, while more aromatic amino acids (Trp and Phe) were exposed to the polar solvent. In addition, the content of random coil of QWFH in solution was increased and its active hydrogen was changed after the PEF treatment. Moreover, the long-range connectivity between OH (14.234 ppm) on 4-H His, N H (7.295 ppm) on 3-H Phe, and N H (6.801 ppm) on 1-H Gln disappeared due to the PEF. PRACTICAL APPLICATIONS: Antioxidants have been extensively explored as a potential drug to decrease the risk of certain chronic diseases. Food-derived bioactive compounds are safer than synthetic antioxidants for human health and well-being. And the PEF technology is one of the promising processes for improving the biological activity of food components. Currently, the activity of the antioxidant peptide QWFH increased after a PEF treatment. The basic structure of QWFH did not change, but the unfolding of the secondary structure on the peptide chain and the displacement of the active hydrogen increased the antioxidant activity of the peptide. Thus, the range of application of a PEF has been expanded and it also benefited the development of more functional factors in the functional food industry.
本研究旨在探究脉冲电场（PEF）提高松子（红松）蛋白中肽谷氨酰胺-色氨酸-苯丙氨酸-组氨酸（QWFH）抗氧化活性的可能机制。通过1,1-二苯基-2-苦基肼自由基清除和氧自由基吸收能力测定，经PEF处理的QWFH的抗氧化能力显著提高（p<0.05）。应用了一系列机制探索方法，包括反相高效液相色谱、紫外吸收光谱、内源荧光光谱、圆二色光谱以及一维和二维核磁共振光谱。PEF处理未使QWFH链断裂，但更多芳香族氨基酸（Trp和Phe）暴露于极性溶剂中。此外，PEF处理后，溶液中QWFH的无规卷曲含量增加，其活性氢发生变化。而且，由于PEF的作用，4-H His上的OH（14.234 ppm）、3-H Phe上的NH（7.295 ppm）和1-H Gln上的NH（6.801 ppm）之间的远程连接消失。实际应用：抗氧化剂作为一种潜在药物已被广泛研究，用于降低某些慢性疾病的风险。食物来源的生物活性化合物对人类健康和幸福而言比合成抗氧化剂更安全。而PEF技术是改善食品成分生物活性的有前景的工艺之一。目前，经PEF处理后抗氧化肽QWFH的活性增强。QWFH的基本结构未改变，但肽链二级结构的展开和活性氢的位移增加了该肽的抗氧化活性。因此，PEF的应用范围得以扩展，这也有利于功能性食品工业中更多功能因子的开发。
