Effects of pulsed electric fields on controlling fermentation rate of brined Raphanus sativus

Abstract

This study investigated the effects of pulsed electric fields (PEF) on the fermentation quality characteristics, morphology, and antioxidant activities of brined and fermented radish with different PEF strengths (1.5 kV/cm. 2.0 kV/cm). Electrical conductivity and Z-index showed that as the strength of PEF increased, the permeability of the cell membrane and the degree of disruption of the cell increased. The pretreatment with PEF accelerated the brining rate, thereby reducing the time required for brining by approximately PEF1.5 kV/cm (56.6%) and PEF2.0 kV/cm (70%) compared to Control. The growth rate of lactic acid bacteria viability was inhibited in the PEF group thus approximately 1–2 log CFU/ml lower than Control. The cellular structure maintenance of radish was improved in the PEF group than in the control group. Altogether, these findings suggest that PEF could effectively increase the storage period (2–5 days) for controlling the excessive growth of lactic acid bacteria which induce overripening during the fermentation of vegetables. Industrial relevanceA fermented food produced by lactic acid bacteria (LAB) is kimchi, a traditional Korean food that is consumed worldwide; however, excessive growth of LAB can reduce the quality of kimchi. PEF technology can be used to control LAB in kimchi to produce a superior product without the addition of antimicrobial agents.