Smoke point

The smoke point also known as burning point of an oil or fat is the temperature at which, under specific and defined conditions, it begins to produce a continuous bluish smoke that becomes clearly visible.[1] Smoke point values can vary greatly, depending on factors such as the volume of oil utilized, the size of the container, the presence of air currents, the type and source of light as well as the quality of the oil and its acidity content, otherwise known as free fatty acid (FFA) content.[2] The more FFA an oil contains, the quicker it will break down and start smoking.[2][3] The higher in quality and the lower in FFA, the higher the smoke point.[4] It is important to consider, however, that the FFA only represents typically less than 1% of the total oil and consequently renders smoke point a poor indicator of the capacity of a fat or oil to withstand heat.[4][5][6]

The smoke point of an oil correlates with its level of refinement.[7][8] Many cooking oils have smoke points above standard home cooking temperatures:

Standard Cooking Temperatures[9]

Pan frying (sauté) on stove top heat: 120 °C (248 °F)

Deep frying: 160 - 180 °C (320 °F - 356 °F)

Oven baking: Average of 180 °C (356 °F)

Smoke point decreases at different pace in different oils.[10]

Considerably above the temperature of the smoke point is the flash point, the point at which the vapours from the oil can ignite in air, given an ignition source.

Oxidative stability

Hydrolysis and oxidation are the two primary degradation processes that occur in an oil during cooking.[10] Oxidative stability is how resistant an oil is to reacting with oxygen, breaking down and potentially producing harmful compounds while exposed to continuous heat. Oxidative stability is the best predictor of how an oil behaves during cooking .[11][12][13] The Rancimat® method is one of the most common methods for testing oxidative stability in oils.[13] This determination entails speeding up the oxidation process in the oil (under heat and forced air), which enables its stability to be evaluated by monitoring volatile substances associated with rancidity. It is measured as “induction time” and recorded as total hours before the oil breaks down. Canola oil requires 7.5 hours, for example, whereas extra virgin olive oil (EVOO) and virgin coconut oil will last over a day at 110 °C of continuous heat.[9] The differing stabilities correlate with lower levels of polyunsaturated fatty acids, which are more prone to oxidation. EVOO is high in monounsaturated fatty acids and antioxidants, conferring stability.[9]

The following table presents smoke points and oxidative stability of various fats and oils:

FatQualitySmoke Point
Almond oil221°C430°F[14]
Avocado oilRefined270°C520°F[15][16]
Mustard oil250°C480°F[17]
Butter150°C302°F[18]
ButterClarified250°C482°F[19]
Canola oil220-230°C[20]428–446°F
Canola oil (Rapeseed)Expeller press190-232°C375-450°F[21]
Canola oil (Rapeseed)Refined204°C400°F
Canola oil (Rapeseed)Unrefined107°C225°F
Castor oilRefined200°C[22]392°F
Coconut oilRefined, dry232°C450°F[23]
Coconut oilUnrefined, dry expeller pressed, virgin177°C350°F[23]
Corn oil230-238°C[24]446-460°F
Corn oilUnrefined178°C[22]352°F
Cottonseed oilRefined, bleached, deodorized220-230°C[25]428–446 °F
Flaxseed oilUnrefined107°C225°F[16]
Lard190°C374°F[18]
Olive oilRefined199-243°C390-470°F[26]
Olive oilVirgin210°C[22]410°F
Olive oilExtra virgin, low acidity, high quality207°C405°F[16][9]
Olive oilExtra virgin190°C374°F[9]
Olive oilExtra virgin160°C320°F[16]
Palm oilDifractionated235°C[27]455°F
Peanut oilRefined232°C[16]450°F
Peanut oil227-229°C[16][28]441-445°F
Peanut oilUnrefined160°C[16]320°F
Rice bran oilRefined232°C[29]450°F
Sesame oilUnrefined177°C350°F[16]
Sesame oilSemirefined232°C450°F[16]
Soybean oil234°C[30]453°F
Sunflower oilNeutralized, dewaxed, bleached & deodorized252-254°C[31]486–489°F
Sunflower oilSemirefined232°C[16]450°F
Sunflower oil227°C[16]441°F
Sunflower oilUnrefined, first cold-pressed, raw107°C[32]225°F
Sunflower oil, high oleicRefined232°C450°F[16]
Sunflower oil, high oleicUnrefined160°C320°F[16]
Grape seed oil216°C421°F
Vegetable oil blendRefined220°C[9]428°F

See also

References

  1. American Oil Chemists' Society (2011). "AOCS Official Method Cc 9a-48, Smoke, Flash and Fire Points Cleveland Open Cup Method". Official methods and recommended practices of the AOCS - (6th ed.). Champaign, Ill. : American Oil Chemists' Society.
  2. 1 2 Thomas, Alfred (2002). Fats and Fatty Oils. Ullmann's Encyclopedia of Industrial Chemistry. Wenheim: Wiley-VCH. ISBN 3-527-30673-0.
  3. Bastida, SS; et al. (2001). "Thermal oxidation of olive oil, sunflower oil and a mix of both oils during forty continuous domestic fryings of different foods". Food Sci Tech Int. 7: 15–21. doi:10.1106/1898-plw3-6y6h-8k22.
  4. 1 2 Gennaro, L. et al., (1998). "Effect of biophenols on olive oil stability evaluated by thermogravimetric analysis". Journal of Agricultural and Food Chemistry. 46: 4465–4469. doi:10.1021/jf980562q.
  5. Gomez-Alonso, S., et al, (2003). "Changes in phenolic composition and antioxidant activity of virgin olive oil during frying". J Agric Food Chem. 51: 667–72. doi:10.1021/jf025932w. PMID 12537439.
  6. Chen, W., et al, (2013). "Total polar compounds and acid values of repeatedly used frying oils measured by standard and rapid methods" (PDF). J Food Drug Anal. 21 (1): 85-85.
  7. Boickish, Michael (1998). Fats and oils handbook. Champaign, IL: AOCS Press. pp. 95–96. ISBN 0-935315-82-9.
  8. Morgan, D.A. (1642). "Smoke, fire, and flash points of cottonseed, peanut, and other vegetable oils". Oil & Soap. 19 (11): 193–198. doi:10.1007/BF02545481.
  9. 1 2 3 4 5 6 Gray, S (June 2015). "Cooking with extra virgin olive oil" (PDF). ACNEM Journal. 34 (2): 8–12.
  10. 1 2 Monoj K. Gupta, Kathleen Warner, Pamela J. White (2004). Frying technology and Practices. AOCS Press, Champaign, Illinois.
  11. Fats and oils in human nutrition. Food and Agriculture Organization of the United Nations and the World Health Organization. 1994. ISBN 92-5-103621-7.
  12. Nwosu, V., et al,. Oxidative Stability of various oils as determined by Rancimat Method. Department of Food Science.: North Carolina State University.
  13. 1 2 Methrom. "Oxidative stability of oils and fats - Rancimat method". Application Bulletin. 204/2 e.
  14. Jacqueline B. Marcus (2013). Culinary Nutrition: The Science and Practice of Healthy Cooking. Academic Press. p. 61. ISBN 978-012-391882-6. Table 2-3 Smoke Points of Common Fats and Oils
  15. "Smoking Points of Fats and Oils." http://whatscookingamerica.net/Information/CookingOilTypes.htm
  16. 1 2 3 4 5 6 7 8 9 10 11 12 13 "Smoke Point of Oils | Baseline of Health". Jonbarron.org. 2012-04-17. Retrieved 2016-05-28.
  17. "Mustard Oil" http://www.clovegarden.com/ingred/oi_mustz.html
  18. 1 2 The Culinary Institute of America (2011). The Professional Chef (9th ed.). Hoboken, New Jersey: John Wiley & Sons. ISBN 978-0-470-42135-2. OCLC 707248142.
  19. "Charts Bin" http://chartsbin.com/view/1962
  20. Vegetable Oils in Food Technology (2011), p. 121.
  21. "What is the "truth" about canola oil?". Spectrum Organics, Canola Oil Manufacturer. Archived from the original on July 24, 2011.
  22. 1 2 3 Detwiler, S. B.; Markley, K. S. (1940). "Smoke, flash, and fire points of soybean and other vegetable oils". Oil & Soap. 17 (2): 39–40. doi:10.1007/BF02543003.
  23. 1 2 Nutiva, Coconut Oil Manufacturer, http://nutiva.com/introducing-nutiva-refined-coconut-oil/
  24. Vegetable Oils in Food Technology (2011), p. 284.
  25. Vegetable Oils in Food Technology (2011), p. 214.
  26. "Olive Oil Smoke Point". Retrieved 2016-08-25.
  27. (in Italian) Scheda tecnica dell'olio di palma bifrazionato PO 64.
  28. Vegetable Oils in Food Technology (2011), p. 234.
  29. Vegetable Oils in Food Technology (2011), p. 303.
  30. Vegetable Oils in Food Technology (2011), p. 92.
  31. Vegetable Oils in Food Technology (2011), p. 153.
  32. "Organic unrefined sunflower oil". Retrieved 18 December 2016.
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