Abstract:

This study was performed to investigate quality changes of kimchi during production by measuring its
physico-chemical and microbiological indexes at the stages of salting and fermentation. The results showed that during
salting, the moisture content of kimchi was decreased from 96.23% to 91.34%. The pH value was decreased slightly to 6.46,
while the total acid amount was increased to 2.91 g/kg. The hardness was decreased by 19.26% to 1 886 N. The numbers of
aerobic bacteria, lactic acid bacteria, yeast and coliforms of kimchi were increased gently during this period. The moisture
content of kimchi was sharply decreased to 82.54% during fermentation. The pH value was decreased to 3.87, while the total
acid amount was increased to 7.02 g/kg. Hardness was decreased by 68.08% to 565 N. L* value (brightness) and a* value
(redness) were increased significantly, while b* value (yellowness) was decreased. The number of aerobic bacteria fell to
the minimum value of 3.3 × 102 CFU/g, while the lactic acid bacteria reached 1.3 × 107 CFU/g. The number of yeast was
decreased remarkably to 9.1 × 102 CFU/g after a slight increase. The number of coliforms was increased to 93 MPN/g on
the 4th day of fermentation, followed by a decrease to lower than 3 MPN/g.

Key words: kimchi, physico-chemical characteristics, microorganism