Analysis and Test Center, Dalian Polytechnic University, Dalian 116034, PR China; College of Food Science and Technology, Jilin University, Changchun 130062, PR China.
Analysis and Test Center, Dalian Polytechnic University, Dalian 116034, PR China.
Food Chem. 2018 Jul 15;254:170-184. doi: 10.1016/j.foodchem.2018.01.090. Epub 2018 Jan 12.
We used a pulsed electric field (PEF) to treat four pentapeptides with similar amino acid sequences (KCHKP, KCHQP, QCHKP, and QCHQP). We then evaluated antioxidant activity of the pentapeptides according to ferric reducing antioxidant power (FRAP) and hydroxyl radical scavenging capacity. Structures of the peptides were determined by high performance liquid chromatography (HPLC), mid-infrared (MIR), circular dichroism (CD) spectroscopy, and nuclear magnetic resonance (NMR). The results indicated that antioxidant activities of KCHQP and QCHKP were increased by PEF, whereas those of KCHKP and QCHQP were reduced. The basic structures and functional groups of peptides were unaffected. PEF treatment reduced the α-helix contents of KCHQP and QCHKP, but increased those of KCHKP and QCHQP. Moreover, the chemical shifts at 14.46 ppm, 8.22 ppm, 7.87 ppm, 7.24 ppm, and 6.13 ppm attributable to hydrogen atoms of QCHKP shifted to the right, but the active hydrogens of QCHQP were not affected by PEF.
我们使用脉冲电场（PEF）处理了四个具有相似氨基酸序列的五肽（KCHKP、KCHQP、QCHKP 和 QCHQP）。然后，根据铁还原抗氧化能力（FRAP）和羟基自由基清除能力评估了五肽的抗氧化活性。通过高效液相色谱（HPLC）、中红外（MIR）、圆二色性（CD）光谱和核磁共振（NMR）确定了肽的结构。结果表明，PEF 处理增加了 KCHQP 和 QCHKP 的抗氧化活性，而降低了 KCHKP 和 QCHQP 的抗氧化活性。肽的基本结构和官能团不受影响。PEF 处理降低了 KCHQP 和 QCHKP 的α-螺旋含量，但增加了 KCHKP 和 QCHQP 的α-螺旋含量。此外，归因于 QCHKP 中氢原子的 14.46 ppm、8.22 ppm、7.87 ppm、7.24 ppm 和 6.13 ppm 的化学位移向右移动，但 QCHQP 的活性氢不受 PEF 影响。
