Influences of electrohydrodynamic time and voltage on extraction of phenolic compounds from orange pomace

Orange pomace, a byproduct of orange juice production, is an important source of phenolic compounds. In this study, the effect of Electrohydrodynamic time (at four levels of 2, 10, 20 and 30 min) and EHD voltage (at four levels of 0, 14, 18 and 22 kV) on the total phenolic compounds (TPC), antioxidant activity (AA), and extraction efficiency (EE) of the extracts from orange pomace powder (OPP) was investigated using Electrohydrodynamic (EHD) process. The results showed that the optimal EHD treatment had the extraction time of 10 min and the voltage level of 18 kV. Under this condition, the TPC, AA, and EE of the extracts were 617.76 +/- 6.15 mg/L, 91.97 +/- 0.43%, and 64.00 +/- 0.00%, respectively. Scanning Electron Microscopy (SEM) pictures illustrated considerable interspaces and pores in the remaining OPP after EHD extraction treatments, compared to the control treatment without EHD process. Moreover, Fourier Transform Infrared (FTIR) spectroscopy of the extracts did not show any destruction of the functional groups of the extracts during EHD process. Therefore, EHD treatment could be an effective method for extraction of natural compounds such as phenolic compounds.