Effect of different salt concentrations and temperatures on the lactic acid fermentation of radish juice

摘要

The characteristics of natural lactic acid fermentation of radish juice were investigated at different salt concentrations (0 approx 2%) and temperatures (10 approx 30 deg C). Major lactic acid bacteria isolated from the radish juice fermented at 2% salt concentration were Leuconostoc mesenteroides, Lactobacillus plantarum, and Lactobacillus brevis. The percentage of lactic acid bacteria against total microbe in the fermented radish juice was over 80% at 0 approx 1% salt concentrations, suggesting the possibility of fermentation even at low salt concentrations. The growth rate of lactic acid bacteria increased with the increase of temperature at 1% salt concentration, but was still active even at 10 deg C. The time to reach pH 4.0 during fermentation of juice of 1% salt concentration was 281 approx 301 hrs at 10 deg C and 50 approx 73 hrs at 30 deg C. The concentrations of sucrose and glucose in the fermented juice were low at high temperatures and were the lowest at a 1.0% salt concentration. However, the content of mannitol showed the opposite trend. Although sour taste, ripened taste, and acidic odor of the fermented juice showed no significant differences among various temperatures and salt concentrations, sensory values of ripened taste and sour acidic were high at high temperatures. The overall quality was the best at 1.0% salt concentration, irrespective of the temperature.