Effects of pulsed electric field (PEF) treatment on physicochemical properties of Panax ginseng

Abstract

Effects of pulsed electric field (PEF) technology on physicochemical properties of raw Panax ginseng roots were investigated in this study. PEF treatment was conducted with different electric field strength (0.5, 1.5, and 2.5 kV/cm) and pulse width of 25 μs. Ginseng cell and vacuole membranes were significantly affected by PEF treatment at field strengths >1.5 kV/cm. Changes in membrane systems due to PEF treatment were verified by increased ion leaching and increased cell membrane disintegration (conductivity disintegration index Z value). Observation by electron microscopy revealed vacuole destruction and plasma membrane separation following PEF treatment. Texture profile analysis showed a significant decrease in hardness (by 44%) and chewiness (by 45%) at 2.5 kV/cm. PEF treatment had little effect on proximate composition and crude saponin content of ginseng roots. However, total phenolic content (by 11%) and antioxidant activity (by 21.4% for DPPH and 3.64% for ABTS) were significantly increased. Industrial relevance: Raw ginseng is normally steamed and dried to make white ginseng and red ginseng. However, using these methods is time consuming and requires much energy. Pulsed electric field (PEF) can induce the changes in physicochemical properties of ginseng with less energy for a short period of time. By using this technology, we can obtain ginseng products with high cell permeability and high antioxidant ability by tailoring the microstructure. This potentially increases the extraction of bioactive compounds in ginseng and significantly enhances the mass transfer during subsequent processing, thereby improving the efficiency of the whole process. These results could be used as basic study for the production of high-quality ginseng products using non-thermal technologies. © 2019 Elsevier Ltd