Effects of Thermooxidation of Soybean Oil in Association with Fried Foods on Quantity Food Production

다량조리 튀김식품 종류에 따른 대두유의 가열산화

  • Choi, Eun-Soo (Dept. of Mechanical Engineering, Myong-ji University) ;
  • Gil, Bog-Im (Dept. of Food and Nutrition, Anyang University)
  • 최은수 (명지대학교 기계공학과) ;
  • 길복임 (안양대학교 식품영양학과)
  • Received : 2011.09.08
  • Accepted : 2011.10.18
  • Published : 2011.10.31

Abstract

Soybean oil used to fry French fries, chicken nuggets, and donuts was exposed to high temperature at $180^{\circ}C$ for 72 h. The effects of frying foods on the thermooxidative stability of soybean oil were evaluated by determining the contents of free fatty acids, peroxides, total polar compounds, and conjugated dienoic acids, and by analyzing dielectric constant, refractive index, iodine value, smoke point, and fatty acid composition. The contents of free fatty acids, total polar compounds, conjugated dienoic acids, dielectric constant, and refractive index increased, whereas iodine value, smoke point, and U/S ratio of fatty acids composition decreased with frying time. All samples of frying oils after 72 h presented free fatty acid contents of below 2.0% and total polar compounds of below 25%, which were within the legal limits. However, peroxide values of frying oils were not directly correlated with frying time. The type of fried food affected the thermooxidative stability of the frying oils, with chicken nuggets being more stable in thermooxidation than French fries and donust. Among physiochemical indicators of frying oil quality, a rapid method including dielectric constant and refractive index can be used in quantity food production.

본 연구는 튀김식품의 종류에 따른 대두유의 가열산화변화를 여러 이화학적 품질지표들을 측정함으로써 장시간 가열처리에 따른 대두유의 산화안정성을 살펴보았다. 튀김유로 대두유를 사용하여 $180^{\circ}C$에서 72시간 동안 프렌치프라이, 치킨너겟, 도넛을 튀겼다. 튀김유의 가열산화 변화를 알아보기 위해 유리지방산가, 과산화물가, 총극성화합물 함량, 공액이중산가를 측정하였고, 유전항수, 굴절률, 요오드가, 발연점, 지방산 조성 중 불포화지방산과 포화지방산의 비(U/S)를 분석하였다. 튀김 시간에 비례하여 유리지방산가, 총극성화합물 함량, 공액이중산가, 유전항수, 굴절률은 증가하고, 요오드가, 발연점, U/S 비는 감소하였다. 모든 튀김유 시료에서 법적 규제치인 산가는 2.0% 이하와 총극성화합물 함량 25% 이하를 나타냈다. 그러나 과산화물가는 튀김 시간과 무관하게 증가와 감소를 반복하였다. 치킨너겟 튀김유가 프렌치프라이나 도넛 튀김유에 비해 가열산화에 더 안정한 것으로 나타나, 튀김식품의 종류가 튀김유 변질 속도에 영향을 주는 것을 알 수 있었다. 튀김유의 품질을 나타내는 여러 이화학적 지표 중 굴절률이나 유전항수는 간편법으로 산업 현장에서 유용하게 이용될 수 있을 것이다.

Keywords

References

  1. Abe I, Oliveira J, Simoes E, Caldas P, Frazao O (2010) Monitoring the quality of frying oils using a nanolayer coated optical fiber refractometer. Talanta 83: 291-293. https://doi.org/10.1016/j.talanta.2010.08.040
  2. Al-Kahtani HA (1991) Survey of used frying oils from restaurants. J Am Oil Chem Soc 68: 857-862. https://doi.org/10.1007/BF02660602
  3. AOCS (1990) Official Methods and Recommended Practices (4th ed.). American Oil Chemists Society, Illinois, USA.
  4. Blumenthal MM (1991) A new look at the chemistry and physics of deep-fat frying. Food Technol 45: 68-71.
  5. Casal S, Malheiro R, Sendas A, Oliveira BPP, Pereira JA (2010) Olive oil stability under deep-frying conditions. Food and Chemical Toxicology 48: 2972-2979. https://doi.org/10.1016/j.fct.2010.07.036
  6. Farhoosh R, Tavassoli-Kafrani MH (2011) Simultaneous monitoring of the conventional qualitative indicators during frying of sunflower oil. Food Chemistry 125: 209-213. https://doi.org/10.1016/j.foodchem.2010.08.064
  7. Firestone D (1993) Worldwide regulation od frying fats and oils. Inform 4: 1366-1371.
  8. Firestone D, Stier RF, Blumenthal MM (1991) Regulation of frying fats and oils. Food Technology 45: 90-94.
  9. Fritsch CW, Eggerg DC, Magnuson JS (1979) Changes in dielectric constant as a measure of frying oil deterioration. J Am Oil Chem Soc 56: 746-750. https://doi.org/10.1007/BF02663054
  10. Givens DI, Gibbs RA, Rymer C, Brown RH (2011) Effect of intensive vs. free range production on the fat and fatty acid composition of whole birds and edible portions of retail chickens in the UK. Food Chemistry 127: 1549-1554. https://doi.org/10.1016/j.foodchem.2011.02.016
  11. Graziano VJ (1979) Portable instrument rapidly measures quality of frying fat in food service operations. Food Technology 33: 50-57
  12. Hunter JE, Applewhite JH (1993) Correction of dietary fat availability estimates for wastage of food service deep-frying fats. J Am Oil Chem Soc 70: 613-617. https://doi.org/10.1007/BF02545329
  13. Naz S, Siddiqi R, Sheikh H, Sayeed SA (2005) Deterioration of olive, corn and soybean oils due to air, light, heat and deep-frying. Food Research International 38: 127-134. https://doi.org/10.1016/j.foodres.2004.08.002
  14. Osawa CC, Goncalves LAG, Ragazzi S (2007) Correlation between free fatty acids of vegetable oils evaluated by rapid tests and by the official method. J Food Composition and Analysis 20: 523-528. https://doi.org/10.1016/j.jfca.2007.02.002
  15. Paul S, Mittal GS (1997) Regulating the use of degraded oil/ fat in deep-fat/oil food frying. Crit Rev Food Sci Nutr 37: 636-662.
  16. Rade D, Mokrovcak Z, Strucelj D (1997) Deep fat frying of French fried potatoes in palm oil and vegetable oil. Food Technol Biotechnol 35: 119-124.
  17. Saguy IS, Dana D (2003) Integrated approach to deep fat frying: engineering, nutrition, health and consumers aspects. J Food Eng 56: 143-152. https://doi.org/10.1016/S0260-8774(02)00243-1
  18. Smith LM, Clifford AJ, Creveling RK, Hamblin CL (1985) Lipid content and fatty acids profiles of various deep fried foods. J Am Oil Chem Soc 62: 996-1001. https://doi.org/10.1007/BF02935700
  19. Swern D (1982) Bailey's industrial oil & fat products. vol. 2. Wiley, New York. pp 325.
  20. Tan YA, Ong SH, Berger KG, Onn HH, Poh BL (1985) A study of the cause of rapid color development heated refined palm oil. J Am Oil Chem Soc 62: 999-1006. https://doi.org/10.1007/BF02935701
  21. White PJ (1991) Methods for measuring changes in deep-fat frying oils. Food Technology 45:75-80.