Improvements in the quality and shelf life of kimchi by fermentation with the induced bacteriocin-producing strain, Leuconostoc citreum GJ7 as a starter.
To improve the quality and self-life of kimchi, the induced bacteriocin-producing lactic acid bacteria (LAB), Leuconostoc citreum GJ7, was introduced into kimchi fermentation as a starter. The kimchi preparations were incubated at 7 degrees C for 12 to 15 d, and then stored at -1 degrees C. Thereafter, changes in their characteristics were monitored for 125 d. When a kimchi starter was introduced into a nonsterile and open kimchi fermentation system, over-ripening of kimchi was prevented during 125 d of storage. In the starter kimchi, Leuc. citreum GJ7 was the dominant organism, comprising 70% to 90% of the total flora, and no yeasts were detected during the entire storage period. However, in the nonstarter kimchi, the predominant LAB could not be determined and yeasts were detected after 50 d of storage. The viable cell number of the starter kimchi was 2 log CFU/mL higher than in the nonstarter kimchi at 125 d of storage. The texture (firmness) of the starter kimchi at 95 to 125 d of storage was similar to that of the nonstarter kimchi at 20 d of storage. Sensory evaluations of texture, off-flavor, and carbonated mouthfeel were significantly improved by the starter-fermentation. The results indicate that the application of the bacteriocin-enhanced Leuc. citreum GJ7 as a starter culture exerts microbial control, prevents over-ripening, and extends the shelf life of kimchi.


CONCLUSIONS
Presently, we have shown that under the optimum fermentation condition the induced bacteriocin-producing LAB, Leuc. citreum GJ7, can regulate natural kimchi fermentation and has extended dominance within the microbial ecology of kimchi. The result is improved quality and shelf life of kimchi. Moreover, to control the growth of other microorganisms in open-fermentation and nonsterile conditions, this system may be usefully adapted for other food or environmental control systems.
Chang
Ji Yoon
JY
Dept. of Food and Nutrition, Chosun Univ., 375 Seosukdong, Donggu, Gwangju 501-759, Republic of Korea.
Chang
Hae Choon
HC
D001430:Bacteriocins / Q000378:metabolism*; D001937:Brassica / Q000378:metabolism* / Q000382:microbiology; D015169:Colony Count, Microbial; D005285:Fermentation / Q000502:physiology*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010858:Pigmentation; D012677:Sensation; D013649:Taste; D013997:Time Factors
D001430:Bacteriocins; C527763:kimchicin GJ7, Leuconostoc citreum GJ7