Effect and Mechanism of CaCl2 Electrolyzed Water Treatment on Improving the Quality of Mung Bean Sprouts

Mung bean seed was soaked and germinated in CaCl2 electrolyzed water (CEW) in order to investigate the effect and mechanism of CEW on preserving the quality of mung bean sprouts. The results showed that after 5 days of storage, the mass loss percentage of mung bean sprouts treated with electrolyzed CaCl2 solution at a concentration of 25 mmol/L decreased, and the hardness and brittleness increased by approximately 1.28 times higher than compared with the control group treated with tap water. The bactericidal effect of CEW was obvious, reducing the microbial load on the surface of mung bean sprouts by nearly one lg (CFU/g). Low-field nuclear magnetic resonance (NMR) spectroscopy showed that the state of water in mung bean sprouts changed, and the bound water content increased. The relative conductivity, malondialdehyde (MDA) content and hydrogen peroxide content decreased by 16.5%, 27.5%, and 36.8%, respectively, the integrity of the cell membrane was maintained, and the accumulation of reactive oxygen species (ROS) was reduced, thus reducing the degree of membrane lipid peroxidation. In addition, the browning of mung bean sprouts during storage was inhibited by CEW treatment, and the mechanism could be related to the decrease in the content of total phenols as browning substrates and the decrease in the activities of polyphenol oxidase (PPO), peroxidase (POd) and phenylalanine ammonialyase (PAL). Therefore, CEW treatment can delay the quality deterioration of mung bean sprouts during storage to a certain extent.