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Factors Effecting the Thermostability of Cooking Oils

Factors Effecting the Thermostability of Cooking Oils. Ryan Barnes. Oil Processing. Frying High temperatures for extended periods of time. What happens to Oil when it is heated?. Hydrolysis Oxidation Polymer Formation. What happens to Oil when it is heated?. Hydrolysis:

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Factors Effecting the Thermostability of Cooking Oils

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  1. Factors Effecting the Thermostability of Cooking Oils Ryan Barnes

  2. Oil Processing • Frying • High temperatures for extended periods of time.

  3. What happens to Oil when it is heated? • Hydrolysis • Oxidation • Polymer Formation Fritsch, C. W., Measurements of frying fat deterioration: A brief review. J Am Oil Chem Soc 1981, 58, 272-274.

  4. What happens to Oil when it is heated? Hydrolysis: • Breaking of triacylglycerol – produces di and mono acylgylcerols along with free fatty acids. These breakdown products produce off flavor and volatile notes.

  5. What happens to Oil when it is heated? • Oxidation (Thermoxidation) • Essentially the same as autoxidation. • Initiation, Propagation, Termination • End products • Aldehydes, Fatty Acids

  6. What happens to Oil when it is heated? • Polymer Formation Chloe, E.; Min, D. B., Chemistry of Deep-Fat Frying Oils. Journal of Food Science 2007, 72, R77-R86.

  7. What happens to Oil when it is heated? Chloe, E.; Min, D. B., Chemistry of Deep-Fat Frying Oils. Journal of Food Science 2007, 72, R77-R86.

  8. End Result of Abused Cooking Oil • Off Odors and Flavors: • Aldehyde and Fatty Acid Breakdown Products • Increase in Polar Compounds: • Glycerols(Mono and Di Acyl) • Some Fatty Acids

  9. Paramters for Cooking Oil Quality • Iodine Value (Degree of Unsaturation) • Free Fatty Acid Content • Total Polar Components • Glycerols,

  10. Factors Effecting Thermostability of Oils • Antioxidants • Degree of Saturation • Gas Composition • Temperature • Number of Fryings/Frying Time

  11. Antioxdiants • Antioxidants such as BHA, TBHQ, and Vitamin E that are used for autoxidation inhibition often degrade at the high temperatures. • There is a need for heat stable antioxidants. Boskou D. 1988. Stability of frying oils. In: Varela G, Bender AE, Morton ID, editors. ChoeE, Lee J. 1998. Thermooxidative stability of soybean oil, beef tallow, and palm oil during frying of steamed noodles. Korean J Food SciTechnol30:288–92

  12. Antioxdiants • Essential Oil (Basil, Cinnamon, Clove, Nutmeg). • Have been shown to have higher radical savaging activity at higher temperatures. Tomaino, A.; Cimino, F.; Zimbalatti, V.; Venuti, V.; Sulfaro, V.; De Pasquale, A.; Saija, A., Influence of heating on antioxidant activity and the chemical composition of some spice essential oils. Food Chemistry 2005, 89, 549-554.

  13. Antioxidants Tomaino, A.; Cimino, F.; Zimbalatti, V.; Venuti, V.; Sulfaro, V.; De Pasquale, A.; Saija, A., Influence of heating on antioxidant activity and the chemical composition of some spice essential oils. Food Chemistry 2005, 89, 549-554.

  14. Antioxidants Tomaino, A.; Cimino, F.; Zimbalatti, V.; Venuti, V.; Sulfaro, V.; De Pasquale, A.; Saija, A., Influence of heating on antioxidant activity and the chemical composition of some spice essential oils. Food Chemistry 2005, 89, 549-554.

  15. Temperature • Higher temperatures more oxidation. • Average Temps (150 – 200oC) • Repeated Heated and Cooling promotes more oxidation. • The solubility of oxygen increases at lower temperatures. Clark WL, Serbia GW. 1991. Safety aspects of frying fats and oils. Food Technology 45:84

  16. Gas Composition • Oxygen is dissolved in oil which helps promote oxidation. • Can be flushed out with either Nitrogen or Carbon Dioxide. • Carbon Dioxide was found to be more effective then Nitrogen. Przybylski, R.; Eskin, N. A. M., A comparative study on the effectiveness of nitrogen or carbon dioxide flushing in preventing oxidation during the heating of oil. Journal of the American Oil Chemists' Society 1988, 65, 629-633.

  17. Frying Time Li, Y.; Ngadi, M.; Oluka, S., Quality changes in mixtures of hydrogenated and non-hydrogenated oils during frying. Journal of the Science of Food and Agriculture 2008, 88, 1518-1523.

  18. Number of Fryings Cuesta, C.; Sánchez-Muniz, F. J.; Garrido-Polonio, C.; López-Varela, S.; Arroyo, R., Thermoxidative and hydrolytic changes in sunflower oil used in fryings with a fast turnover of fresh oil. Journal of the American Oil Chemists Society 1993, 70, 1069-1073

  19. How to prolong thermoxidation of your frying oil: • Heat Stable Antioxidants • Cook all at once • Temperature Control • Control Gas Composition Prior to Processing

  20. Questions?

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