4. Results and Discussions
Changes in pH, acidity and reducing sugar content during kimchi fermentation.
This figure shows the biochemical changes in kimchi during fermentation.
Optimum taste is attained when the pH and acidity reach approximately 4.0-4.5 and 0.5-0.6 (lactic acid equivalent %), respectively.
Vitamin C content is maximal at this point . At a higher fermentation temperature, the ripening time is decreased; kimchi ripens in 1 week at 15 and in 3 days at 25.
Changes in microflora during during kimchi fermenation. Adapted from Lee (2001)
A Before-ripening, Leuconostoc mesenteroides is the dominant microorganism, whereas Lactobacillus species are the major organisms in overripened kimchi.
Lactobacillus plantarum and Lactobacillus brevis dominate fermentations carried out at 20-30 while Lactobacillus maltaromicus and Lactobacillus
bavaricus dominate at 5-7. Lb. plantarum is homofermentative and is the highest acid-producing species of this group. Low temperature is preferred for kimchi
fermentation to prevent the production of high amounts of lactic acid and over-ripening as well as to extend the period of optimum taste.