Effects of Freeze-Drying Time on Quality of Freeze-Dried Kimchi

동결건조 시간이 동결건조김치의 품질에 미치는 영향

  • Ko, Young-Tae (Department of Foods and Nutrition, Duksung Women's University) ;
  • Kang, Jung-Hwa (Department of Foods and Nutrition, Duksung Women's University)
  • 고영태 (덕성여자대학교 식품영양학과) ;
  • 강정화 (덕성여자대학교 식품영양학과)
  • Published : 2002.02.01

Abstract

Effects of freeze-drying time on the microbiological, sensory, and other characteristics of freeze-dried kimchi were investigated to optimize freeze-drying time for kimchi. Quality attributes of freeze-dried kimchi, including number of lactic acid bacteria (LAB), pH, sensory properties, brittleness, rehydration property, moisture content, and microstructure of Chinese cabbage were observed for 24, 48 and 72 h, respectively. Number of LAB and pH of the kimchi freeze-dried for 24 h were significantly changed in comparison with those of the kimchi not freeze-dried. However, further freeze-drying did not change markedly number of LAB and pH. Overall acceptability of the sample freeze-dried for 48 of 72 h was better than that of the sample freeze-dried for 24 h. As freeze-drying time increased, brittleness of the dried sample increased, and rehydration property was improved while dried weight and moisture content of the sample decreased. In conclusion, the sample freeze-dried for 48 h was better than the sample freeze-dried for 24 or 72 h, based on sensory properties and other characteristics.

본 연구의 목적은 동결건조된 김치를 시료로 선정하여 동결건조 시간이 건조된 김치제품의 미생물학적인 특성, 관능적 특성 및 다른 품질에 미치는 영향을 조사하여 "건조김치"의 제조에 적합한 동결건조 시간을 알아내는 것이다. 김치를 24, 48, 72시간 동결건조한 후, 건조제품의 젖산균수, pH, 관능적 특성, 파쇄도, 복원성 및 수분함량, 배추조직의 미세구조를 관찰하여 동결건조 시간이 건조김치의 품질에 미치는 영향을 조사하였다. 원시료에 비하여 24시간 건조시킨 제품의 생균수 및 pH가 현저하게 변화하였으나, 그 후에는 72시간까지 거의 변화가 없었다. 24시간 건조김치보다 48시간 또는 72시간 건조김치의 전반적인 기호성이 우수하였다. 동결 건조 시간이 24시간에서 48시간, 72시간으로 증가할수록 건조김치의 파쇄성은 증가하였다. 동결건조 시간이 경과할수록 건조김치의 복원성이 개선되고, 건조김치의 중량과 함유된 수분함량은 감소하였다. 본 실험의 조건하에서는 건조김치의 제조에 적합한 동결건조 시간은 미생물학적인 측면에서 보면 24시간도 큰 문제는 없으나, 관능적 특성과 건조제품의 품질특성의 측면에서 판단하면 48시간이 보다 바람직하였다.

Keywords

References

  1. Jo, J.S. Studies on Kimchi, pp. 261-339. Yurim-munhwasa, Seoul (2000)
  2. Kim, M.H. and Chang, M.J. Influence of organic acid or ester addition on kimchi fermentation. Foods and Biotechnol. 4: 146-149 (1995)
  3. Choi, S.Y, Lee, I.S., Yoo, J.Y., Chung, K.S. and Koo, Y.J. Inhibi tory effect of nisin upon kimchi fermentation. Kor. J. Appl. Microbiol. Biotechnol. 18: 620-623 (1990)
  4. Moon, K.D., Byun, J.A., Kim, S.J. and Han, D.S. Screening of natural preservatives to inhibit kimchi fermentation. Kor. J. Food Sci. Technol. 27: 257-263 (1995)
  5. Ryu, H.J., Chung, C.H. and Kyung, K.H. Evaluation of nisin as a preservative to prevent over-acidiScation of kimchi. Food Sci. Biotechnol. 7: 205-208 (1998)
  6. Kim, S.J. and Park, K.H. Retardation of kimchi fermentation by the extracts of Allium tuberosum and growth inhibition of related microorganisms. Kor. J. Food Sci. Technol. 27: 813-818 (1995)
  7. Yun, S.I. Method to increase preservation of kimchi by addition of cinnamon oil. Korean Patent 1002 (1990)
  8. Chung, D.K. and Yu, R. Antimicrobial activity of bamboo leaves extract on microorganisms related to kimchi fermentation. Kor. J. Food Sci. Technol. 27: 1035-1038 (1995)
  9. Lee, S.H., Choi, W.J. and Im, Y.S. Effect of Scizandra chinensis (Omija) extract on the fermentation of kimchi. Kor. J. Appl. Microbiol. Biotechnol. 25: 229-234 (1997)
  10. Ahn, S.C. and Lee. G.J. Effects of salt-fermented fish and chito-san addition on the pectic substance and the texture changes of kimchi during fermentation. Kor. J. Soc. Food Sci. 11: 309-315 (1995)
  11. Son, Y.M., Kim, K.O., Jeon, D.W. and Kyung, K.H, The effect of low molecular chitosan with or without other preservatives on the characteristics of kimchi during fermentation. Kor. J. Food Sci. Technol. 28: 888-896 (1996)
  12. Kim, K.O., Moon, H.A. and Jeon, D.W. The effect of low molec ular weight chitosans on the characteristics of kimchi during fer-mentation. Kor. J. Food Sci. Technol. 27: 420-427(1995)
  13. Park, K.H., Seo, B.C., Han, J.S. and Na, S.I. Method to prolong ripening of kimchi by addition of glucono-delta-lactone. Korean Patent 3501 (1993)
  14. An, D.J., Lew, K.C. and Lee, K.P. Effects of adipic acid and stor-age temperature on extending the shelf-life of kimchi. Food Sci. Biotechnol. 8: 78-82 (1999)
  15. Lee, C.Y., Kim, H.S. and Chun, J.K. Studies on the manufacture of canned kimchi. J. Kor. Agri. Chem. Soc. 10: 33-38 (1968)
  16. Kim, C.S., Kim, J.H. and Jung, M.H. Method of preparation of kimchi can. Korean Patent 850 (1966)
  17. Lee, N.J. and Chun, J.K. Studies on the kimchi pasteurization. Part II. Effects of kimchi pasteurization conditions on the shelf-life of kimchi. J. Kor. Agri. Chem. Soc. 25: 197-200 (1982)
  18. Park, K.H., An, S.Y. and Yook, C. Method to prevent detedora-tion of kimchi by pre-heat treatment. Korean Patent 22 (1987)
  19. Cha, B.S., Kim, W.J., Byun, M.W., Kwon, J.H. and Cho, H.O. Evaluation of gamma irradation for extending the shelf life of kimchi. Kor. J. Pood Sci. Technol. 21: 109-119 (1989)
  20. Byun, M.W., Cha, B.S. Kwon, J.H., Cho, H.O. and Kim, W.J. The combined effect of heat treatment and irradiation on the inactivation of major lactic acid bacteria associated with kimchi fermentation. Kor. J. Food Sci. Technol. 21: 185-191(1989)
  21. Byun, M.W. and Kwon, J.H. Method of long term storage of Chinese cabbage kimchi. Korean Patent 5282 (1991)
  22. Ko, Y.T, Kang, J.H. and Kim, T.E. Quality of Freeze Dried Kim-chi. Kor. J. Food Sci. Technol. 33: 100-106 (2001)
  23. Sun Scientific Co., User's Manual of Rheometer Model Compac-100, Sun Scientific Co., Tokyo, Japan (1999)
  24. Larmond, E. Laboratory methods for sensory evaluation of food, Canada Department of Agriculture, Ottawa, Canada (1977)
  25. AOAC Official Methods of Analysis, 15th ed., 934.06, Moisture in dried fruits, Association of Official Analytical Chemists, Wash-ington, DC, USA (1990)
  26. Jandel Co. SigmaStat for Windows. V 1.02, Jandel Co., USA (1994)
  27. Ko, Y.T. and Lee, E.J. Freeze drying of lactic acid bacteria fer-merited food prepared from egg white powder and casein supple-merited with growth stimulating agent. Kor. J. Food Sci. Technol. 31: 1337-1344 (1999)