Review on the research and application of electrolytic water technology in postharvest preservation of fruits and vegetables

Abstract: Electrolysis Water (EW) has been widely used as a non-thermal technology in agriculture, medical treatment, and food processing in recent years. Particularly, EW technology is ever-increasing in the postharvest preservation and commercial treatment of fruits and vegetables, due to its environmental friendliness, cost saving, as well as high safety and efficiency. The purpose of this review is to further understand the relevant research progress of EW technology in the postharvest and preservation field, with emphasis on the pros and cons. A technical and mechanism summary of EW was performed mainly on the inhibition of microorganisms, the removal of pesticide residues, and preservation quality improvement. The process mode and the Patent application Status of EW technology were also summarized for the postharvest fruits and vegetables in recent years. The results showed that as follows. (1) The different functions were derived from the EW physical and chemical characteristics, such as Acid Electrolytic Water (AEW), Alkaline Electrolytic Water (AlEW), New Water (NEW), Slightly Acidic Electrolytic Water (SAEW), Electrolytic Oxidized Water (EOW), Electrolytic Reducing Water (ERW), and Low Concentration Electrolytic Water (LcEW), especially with the development of EW preparation. Furthermore, there was no systematic application for the different types of EW in the postharvest preservation field. (2) Sufficient technical and theoretical research was found about the AEW and SAEW to remove and inhibit the food-borne microorganisms in fruits and vegetables, especially in fresh-cut vegetables. The low pH value, the active chlorine component, and the high redox potential of acid EW cooperated to effectively inactivate bacteria. However, it was still lacking in the inhibition of fruit and vegetable disease and decay fungi. There was no specific anti-fungal technology and anti-bacterial mechanism so far. (3) A large number of studies reported that the acidic, alkaline and oxidizing EW dominated the removal of pesticide residues on the surface of fruits and vegetables. However, the specific mechanism was a high demand for the AEW and SAEW degradation of organophosphorus pesticides. Much effort can be focused on the alkaline electrolytic water degradation of pesticide residues, as well as the EW degradation of organochlorine and permethrin pesticides. (4) The EW treatment can be expected to effectively improve the resistance for the less chilling injury, or the Browning of fruits and vegetables. But the specific efficacy and mechanism of EW needed to be clarified for the better quality and preservation of fruits and vegetables. In addition, the scarce patent application of special EW technology and equipment cannot fully match the ever-increasing market demand for the postharvest preservation of fruits and vegetables in China. Therefore, this review can provide the theoretical basis and guidance for the application of EW technology in the field of postharvest fruits and vegetable preservation.