High-voltage technologies for agriculture and food processing

Abstract

High-voltage technologies, including plasma, are used in agriculture and food processing applications. Repetitively operated, compact high-voltage power supplies with moderate peak power have been developed for controlling discharge plasmas and electric field distribution for agricultural and food processing applications. These applications are mainly based on the biological effects of a spatially distributed electric field and the chemically active species produced by the plasma. The intense pulse electric fields (PEFs) that have biological effects are caused by applying pulse voltage between the electrodes. When the applied voltage exceeds the corona discharge criterion, discharge plasmas that produce free radicals, UV radiation, an intense electric field and shock waves are generated by the accelerated electrons within the intense electric field in a gas or liquid medium. Different high voltages and plasmas may have different biological effects on substrates via the electric field and reactive species. For instance, intense electric fields form pores on the cell membrane (i.e. electroporation) or influence the nucleus. The agricultural applications of plasma are categorized as seed germination promotion, plant growth acceleration, the inactivation of bacteria in soil and liquid hydroponic media, and the promotion of fruit-body formation such as in mushrooms and fruits in the pre-harvest phase. In the postharvest phase, maintaining the freshness of agricultural products is important for a sustainable food supply chain. High-voltage and plasma technologies can contribute to maintaining freshness by decontaminating the air and liquid in agricultural products storage containers. In the food processing phase, an intense PEF can be used to extract juice, nutritional agents and antioxidant metabolites such as vitamin, carotenoids and polyphenols from fruits and vegetables. Some foods and liquors are made by fermenting a food substance. Fermentation is a metabolic process enabled by yeast and bacteria, the activity of which can be controlled by an intense electric field.

Biomedical Applications of Electromagnetic Detection: A Brief Review

“…Takaki et al introduced vegetables and fruits with a high-voltage electrostatic field. Compared with the control group, the storage time of the juice after the treatment was prolonged [63]. As for meat products, Wen-Ching Koa et al used 100 kv/m high-voltage electrostatic treatment on tilapia.…”

Surface Modification of FeCoNiCr Medium-Entropy Alloy (MEA) Using Octadecyltrichlorosilane and Atmospheric-Pressure Plasma Jet

“…Various electrode configurations and excitation methods generate APPs with different gas and electron temperatures [28]. APP with low gas temperature has been used for applications in biomedicine, food processing, and agriculture [29,30]. An APP with an intermediate gas temperature (of the order of several hundred degrees Celcius) can be used for rapid materials processing by taking advantage of the synergetic effect of heat and reactive plasma species [28,[31][32][33][34][35][36][37][38][39][40][41].…”

Pulsed Power Applications for Protein Conformational Change and the Permeabilization of Agricultural Products

“…The food processing applications of pulsed power technologies, such as intense pulsed electric fields and time-modulated discharge plasmas, have been studied worldwide, and interest in them among researches is growing rapidly [ 1 ]. The repetitive operation compact pulsed power generators with moderate peak power suitable for use in food processing applications have been developed by many researchers for temporal and spatial control of intense electric fields and discharge plasmas.…”

“…When the pulsed high voltage is applied between arbitrarily shaped electrodes, intense pulsed electric fields (PEFs) are produced between the electrodes, which causes biological effects such as electroporation (formation of pores) of cell membranes [ 5 ] and conformational change in proteins [ 6 ]. These phenomena can be used in food proceedings such as drying, pasteurization (sterilization of bacteria), permeabilization and fermentation [ 1 ]. The poration of cell membranes by PEFs also contributes an improvement in the extraction of juice, nutritional agents and antioxidant metabolites, such as polyphenols from agricultural produce [ 7 ].…”