Fermentation control of kimchi by high-pressure treatment and characteristics

The commercial-scale feasibility of high-pressure treatment to fermented foods was investigated, with attention given to the fact that the pressure resistance varies with the kind of microorganism. Kimchi was chosen because lactic acid bacteria had been found to be separated from yeast by pressure application of 300 MPa (20°C), and subjected to pressure treatment to investigate the microbiological, physicochemical and sensory changes with the progress of fermentation. Pressure application of 300 MPa (20°C) to Kimchi for 5 minutes slightly decreased the number of lactic acid bacteria, while completely inactivated the yeast to prevent expansion of the Kimchi-containing package during the storage. The pressure treatment also reduced the generation of lactic acid, the drop in pH value and the decrease of glucose and fructose contents. Although the pressure-treated Kimchi showed increased color difference and translucence, the breaking stress was not changed. The sensory tests demonstrated the advantages of pressure-treated Kimchi, to confirm the improvement of shelf life of Kimchi.