Journal of Food Hygiene and Safety (한국식품위생안전성학회지)

The Korean Society of Food Hygiene and Safety (한국식품위생안전성학회)
권호 표지
DOI QR코드

DOI QR Code

Enhancement of Konjac Storage by Controlling pH of Coagulant and Soaking Liquid

응고제와 침지제의 pH 조절에 따른 곤약의 저장성 강화

  • Choi, Ung-Kyu (Department of Food Science & Technology, Koera National University of Transportation)
  • 최웅규 (한국교통대학교 식품공학과)
  • Received : 2018.10.18
  • Accepted : 2019.01.23
  • Published : 2019.02.28
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, viable cells, coliforms and food poisoning bacteria were identified according to the pH levels of the coagulant and immersion liquid during each stage in the production of konjac, and storage stability was confirmed for 3 months. A considerable number of bacteria were found in the raw material, or powdered konjac (Amorphophallus konjac), as well as in the processing water. However, it has been shown that the plastic package were safe from microorganisms. Due to the high pH of the added coagulant [2.0% $Ca(OH)_2$], no contaminating bacteria were observed after konjac jelly formation. Coliforms were not detected any of the tested steps. During the molding process, the pH of konjac was adjusted to 9.5 ~ 12.5 at intervals of 0.5, and the number of bacteria was determined. As a result, no bacteria were detected in the alkaline range above pH 11.5. The pH of the immersion liquid was adjusted to 10.0 ~ 12.5, and after hardening, the konjac were stored at room temperature for 12 weeks. As a result, no bacteria, Escherichia coli or other food poisoning bacteria were detected at pH 11.5 or higher. Based on these results, it is expected that when the pH levels of the konjac and its immersion liquid are maintained at 11.5, it should be possible to keep the product for 3 months without additional sterilization process.

본 연구에서는 곤약 제조시 각 생산단계별, 응고제 및 침지액의 pH에 따른 일반세균, 대장균군 및 식중독균을 확인하고 저장 3개월 동안의 저장안전성을 확인하였다. 곤약의 주원료인 구약감자 분말과 가공용수는 살균과정을 거치지 않아 상당한 수의 일반세균을 포함하고 있으며, 비닐포장은 미생물학적으로 안전한 것으로 판단되었다. 곤약 제조단계별 미생물을 확인한 결과 겔 형태의 곤약 성형단계에서 일반세균이 검출되지 않았는데 이는 첨가된 응고제인 2.0% $Ca(OH)_2$의 높은 pH의 작용에 기인하는 것으로 판단되었다. 이후 모든 공정에서 공정 모두에서 일반세균수가 검출되지 않았다. 대장균군은 시험 전 단계에서 검출되지 않았다. 성형공정에서 곤약의 pH를 9.5~12.5까지 조정하여 굳힌 후 일반세균수를 확인한 결과 pH 11.5보다 알카리 범위에서는 일반세균이 전혀 검출되지 않았다. 침지액의 pH 범위를 10.0~12.5까지 조정하여 굳힌 후 12주동안 상온에서 저장하면서 미생물수를 확인한 결과 pH 11.5이상에서는 일반세균, 대장균 및 식중독균이 전혀 검출되지 않음을 확인할 수 있었다. 이러한 결과를 바탕으로 응고시 곤약의 pH와 침지액의 pH를 11.5로 설정할 경우 별도의 살균과정 없이 3개월이상 유통이 가능할 것으로 기대되며, pH의 조절만으로 이를 가능하게 함으로써 공정의 간편 효과도 얻을 수 있을 것으로 사료된다.

Keywords

References

  1. Kishida N.: Relationship between the quality of konjac flour and the molecular matter nature of konjac-mannan. Agr. Biol. Chem. Tokyo, 43, 2391-2397 (1979).
  2. Yoo M.H., Lee H.G., Lim S.T.: Physical properties of the films prepared with glucomannan extracted from Amorphophallus konjac. Korean J. Food Sci. Tech., 29, 255-260 (1997).
  3. Bark S.J., Kang M.H.: The effect of dietary noodle with glucomannan on the weight loss in high fat diet-induced obese rats. J. Korean Soc. Food Sci. Nutr., 32, 893-898 (2003). https://doi.org/10.3746/jkfn.2003.32.6.893
  4. Bark S.J., Kang M.H.: The dietary effect of patty made with added glucomannan in high fat diet-induced obese rats. J. East Asian Soc. Diet. Life., 15, 40-48 (2005).
  5. Sim J.I., Choi S.J., Jeong J.H., Choi U.K.: Establishment of optimum condition for the coagulation and antimicrobial activity of konjac jelly. Korean J. Food Culture., 29, 415-420 (2014). https://doi.org/10.7318/KJFC/2014.29.5.415
  6. Sim J.I., Choi S.J., Jeong J.H., Choi U.K.: Selection of the coagulant for processing and identification of antibacterial activity on foodborn pathogens of konjac Jelly. Korean J. Food Nutr., 27, 699-705 (2014). https://doi.org/10.9799/ksfan.2014.27.4.699
  7. Lee S.K., Sin G.L., Kim Y.H.: Effect of mixed glucomannan and whey calcium on the serum cholesterol and blood glucose in rats. J. Fd. Hyg. Safety., 20, 69-72 (2005).
  8. Kim S.J., Choi W.S., You S.G., Min Y.S.: Effect of glucomannan on quality and shelf-life of low-fat chicken patty. Korean J. Food Sci. Technol., 39, 55-60 (2007).
  9. Choi H.E., Park H.Y., Jo Y.I., Kim N.Y., Lee N.H., Choi U.K.: Effect on the characteristics of noodle by the addition of konjac powder. Korean J. Food Nutr., 30, 282-289 (2017). https://doi.org/10.9799/ksfan.2017.30.2.282
  10. Choi H.E., Park H.Y., Kim N.Y., Jang H.S., Lee N.H., Choi U.K.: Cooking characteristics of noodle containing konjac powder and Capsosiphon fulvescens. Korean J. Food Nutr., 30, 847-851 (2017). https://doi.org/10.9799/ksfan.2017.30.4.847
  11. Lee N.H., Choi W.S., Choi U.K.: Optimization for the antibacterial activity of konjak jelly using evolutionary operation-factorial design technique. Korean J. Food Nutr., 31, 272-277 (2018). https://doi.org/10.9799/KSFAN.2018.31.2.272
  12. Ministry of Food and Drug Safety. Korean Food. Code. Chapter 9. General analytical method. 9-3-3.5-9-3-3.25. Retrieved from http://www.foodsafetykorea.go.kr/portal/safefoodlife/food/foodRvlv/foodRvlv.do on Apr 3. (2016).
  13. Ministry of Food and Drug Safety. Method of Investigation of cause in Food poisoning. Retrieved from http://www.mfds.go.kr/index.do?searchkey=title:contents&mid=695&searchword=foodpoisoning&cd=&pageNo=1&seq=20737&cmd=v on Apr (2015).
  14. Oh S.W., Hong S.P., Kim H.J., Choi Y.J.: Antimicrobial effects of chitosans on Escherichia coli O157:H7, Staphylococcus aureus and Candida albicans. Korean J. Food Sci. Technol. 32, 218-224 (2000).