高压脉冲电场技术提高红松籽抗氧化肽活性

Improvement of antioxidant peptides activity of Korean pine seed by pulsed electric field technology

为了研究用高压脉冲电场技术（pulsed electric field, PEF）提高红松子抗氧化肽活性的效果,该文以分子量1~3kDa的红松籽多肽为试验原料,以2,2-二苯基-1-苦基肼（2,2-diphenyl-1-picrylhydrazyl,DPPH）清除率为衡量指标,借助单因素和响应面试验设计方法,优选高压脉冲电场技术处理红松籽抗氧化肽的最佳工艺参数.研究发现,当电场强度11.5 kV/cm,脉冲频率1 500 Hz,流速4.8 mL/min时,PEF处理的红松籽抗氧化肽粉的DPPH清除率为86.93%±0.31%,比未经PEF处理的DPPH清除率68.16%±0.25%,提高了18.77%;通过中红外色谱技术（mid-infrared spectroscopy, MIR）分析了最佳PEF处理的1-3 kDa红松籽抗氧化肽粉,发现其二级结构中R2C=CH2键和-CH3发生改变,研究结果为探究PEF技术提高抗氧化肽的机理提供参考.

The effects of pulsed electric field （PEF） on auxiliarily improving activity of antioxidant peptides were investigated. In this study, the Korean pine seed antioxidant peptides with molecular weight ranging from 1 to 3 kDa were used as raw materials and 1,1-diphenyl-2-picryl-hydrazyl （DPPH） radical inhibition was used as testing index. In order to develop and optimize the parameters of DPPH radical inhibition, we have investigated 3 variables, including electric field intensity （kV/cm）, pulse frequency （Hz） and flow velocity （mL/min）. By means of one-factor-at-a-time （OFAT） and response surface metrology （RSM） experiment, the technological parameters of the PEF treatment were optimized. The OFAT research showed that the DPPH radical inhibition reached the highest value 89.08%±1.08% when the residence time of the treated sample by PEF was 4 h, the DPPH radical inhibition reached the highest value 90.53%±0.85% when the electric field intensity was 12.5 kV/cm, and the DPPH radical inhibition reached the highest value 89.08 %± 0.54 % when the ratio of electric frequency was 2000 Hz. Based on the RSM research, the results showed that, the electric field intensity of PEF was 11.5 kV/cm, the pulse frequency was 1494 Hz, the flow velocity was 4.8 mL/min, the predictive value of the DPPH radical inhibition was 83.58%. Taking into account the specific conditions of the device, the process parameters were corrected for the electric field intensity of PEF treatment to be 11.5 kV/cm, the pulse frequency to be 1500 Hz and the flow velocity to be 4.8 mL/min. And under this condition, the DPPH radical inhibition was 86.93%＆#177;0.31%. While the DPPH radical inhibition was 68.16%±0.25% when the sample Korean pine seed antioxidant peptides did not be treated by PEF. The removal rate of DPPH was increased by 18.77% compared with the untreated by PEF. The Mid-infrared spectroscopy （MIR） was used to analyze the structure of Korean pine seed antioxidant peptides under the optimal PEF conditions and the results showed that 2 spectra （one spectral was the sample treated by PEF under the optimized condition, another spectral was the sample untreated by PEF.） in the 3 305-3 475 cm-1 region had stronger absorption peaks which may contain R-OH, and R-NH-R＆#39; and R-NH2; in the 1 395-1 410 cm-1 region had stronger absorption peaks in which R-OH may exist; in the 1035-1065 cm-1 region had stronger absorption peaks which may contain R-OH, R-O-R′, Ar-O-R′, R-NH2, R-NH-R′, R-NR″-R′. While the treated samples by PEF had strong absorption peaks in the 800-900 cm-1 region, in which the R2C=CH2 may exist; there was a strong absorption peak in the 2 970-2 980 cm-1 region, in which the -CH3 may exist. Analysis showed that treated by pulsed electric field, the improvement of DPPH radical inhibition rate may be due to the changes in the R2C=CH2 and CH3 keys in Korean pine seed antioxidant peptides. The result is to provide a reference for the research of PEF technology to improve the active mechanism of antioxidant peptides.