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Lipid Oxidation with special consideration for n-3 fatty acids

Lipid Oxidation with special consideration for n-3 fatty acids. By Amber Lynn Vecera. What’s the big deal?. Generally, very low oxidative stability Can potentially “design” food systems that allow for higher oxidative stability Antioxidants Encapsulation Modified Atmosphere Packaging

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Lipid Oxidation with special consideration for n-3 fatty acids

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  1. Lipid Oxidationwith special consideration for n-3 fatty acids By Amber Lynn Vecera

  2. What’s the big deal? • Generally, very low oxidative stability • Can potentially “design” food systems that allow for higher oxidative stability • Antioxidants • Encapsulation • Modified Atmosphere Packaging • Some food matrices offer an excellent environment for omega-3 to be incorporated with a low risk of oxidaiton

  3. Pro-oxidants • Enzymes • Heat • Aw • Reactive Oxygen Species (ROS) • Metal ions • Chlorophyll • Light • Irradiation

  4. Mechanism of Oxidation • Catalytic event that causes the initiation of the oxidation • Radical attack • Attacks adjacent to the double bond • Electron shifting • Oxygen addition • Excited oxygen • Direct addition on either side of the double bond • Scission

  5. Oxidation of Linolenic Acid C18:3(n-3) Attack at C11

  6. Primary Oxidation Products • Peroxides adjacent to any of the original double bonded carbons • Upon addition of H become Hydroperoxides • Often produce conjugated dienes

  7. Secondary Oxidation Products • Aldehydes, ketones, alcohols, carboxylic acids • Variety makes it hard to measure degree of oxidation

  8. Secondary Oxidation Product Effects • Protein cross-linking • Covalent bonds to nucleic acid

  9. Effects of Ingesting Oxidized Lipids • Fetal reabsorption in rats • Carcinogenic • Cardiovascular disease • Atherosclerosis • BUT… oxidized EPA as an anti-inflammatory?

  10. “…beneficial effects of fish oil in chronic inflammatory diseases… may result from the inhibitory effects of oxidized omega-3 fatty acids on pro-inflammatory events…”

  11. Looks like we have more research to do…. • Obviously, this does not apply to all inflammatory cases. • However…. It is very interesting…. • Can this be repeated with other fatty acids? • Do the experimental levels of oxidized fatty acids actually represent levels found in the body? • Can we create the effective “acting” molecules instead of relying on the random mix of oxidized fatty acids to fall this way every time? • Can it be applied to other inflammatory systems? • What populations does this phenomenon apply to?

  12. For our intents and purposes, let’s continue with the idea of preventing lipid oxidation.

  13. Combative Action • Prevent oxidation: • Scavenge free radicals • Prevent reactive oxygen species in the first place • Chelate metal ions that produce the ROS • Sequester primary oxidation products • But how?

  14. Preventing Lipid Oxidation • Antioxidants, especially polyphenols • Modified Atmosphere Packaging • Encapsulation

  15. Re-cap • Omega-3 Fatty Acids can increase health • We must find practical and effective ways to protect them • Understanding their mechanism of oxidation is the first step to combating this problem.

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