Optimization of pulsed electric field assisted extraction of lycopene and phenolic compounds from tomato waste

In the present study, to optimize the lycopene and phenolic compounds extraction from tomato paste, pulsed electric field in different intensities including 2, 4, 6 KW. Cm-1 and different pulse numbers including 10, 30, 60 were designed and applied. Therefore the extraction efficiency of lycopene and phenolic compounds, DPPH free radical scavenging activity as well as ferric reducing activity of the extracted oil were predicted. The statistical analysis and optimization process with the use of response surface methodology were performed. The achieved results presented that with enhancements in pulsed electric field intensity, at the beginning parameters including the efficiency of lycopene extraction and phenolic compounds extraction, DPPH free radical scavenging activity and ferric reducing power increased and then showed reductions. With enhancements in pulse number, at the beginning lycopene extraction slightly decreased then showed enhancements, but the phenolic compounds extraction rate as well as DPPH free radical scavenging activity increased slightly. The achieved results of optimization process expressed that to obtain extracts with high quantities of lycopene and phenolic compounds, pulsed electric field and pulse number should be set on 3.7 KW. Cm-1 and 6 respectively to achieve the desirability value equals to 0.915. Finally the achieved results of the comparison of control sample with the treated ones expressed that,  treated sample with pulsed electric field presented higher quantities for the extracted lycopene and phenolic compounds, DPPH free radical scavenging activity as well as reducing power (111.4, 45.64, 146.28 and 73.43) compared to the standard samples.