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AVEQ

AVEQ. WP 8 Antioxidants in Oats Lena Dimberg and Rita Redaelli. Outline. Why antioxidants? Antioxidants in oats Tocopherols /tocotrienols/avenanthramides Bioactivities Effects of processing Effects of cultivation measures Concluding remarks. Oxidation.

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AVEQ

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  1. AVEQ WP 8 Antioxidants in Oats Lena Dimberg and Rita Redaelli

  2. Outline • Why antioxidants? • Antioxidants in oats • Tocopherols /tocotrienols/avenanthramides • Bioactivities • Effects of processing • Effects of cultivation measures • Concluding remarks

  3. Oxidation Oxidation of lipids generates free radicals which are very reactive • may results in reduction of shelf-life of foods • may cause damage to various body tissues, and may thereby initiate various diseases

  4. Antioxidants Antioxidants effectively retard the onset of lipid oxidation with different mechanisms • may protect food from rancidity • may protect the body from free radical damages

  5. Antioxidants • Ascorbic acid (Vitamin C) • Carotenoids (Vitamin A precursors) • Tocopherols/tocotrienols (Vitamin E) • Phenols

  6. Phenols in Foods • Color • Flavor and aroma • Texture • Keeping qualities • Pharmacological effects

  7. Tocopherols/ tocotrienols tocopherols tocotrienols

  8. NP-HPLC OF TOCOLS Pisacane et al. 2004

  9. Tocopherols/tocotrienols-bioactivities- Preventive of foetuses' death Membrane stabilizer Antioxidants structure-activity relationship

  10. Tocopherols/tocotrienols Tocopherols- in germ Tocotrienols – in endosperm Genetic variability Tocotrienols are positively related to the oil content

  11. Range of variation in tocol content

  12. Avenanthramides R= H, OH or OCH3 n= 1 or 2

  13. Avenanthramides-bioactivities Antioxidative Structure- activity relationship Anti-atherosclerotic Anti-inflammatory Tranilast look alike Phytoalexin/Antifungal Cooling sensation

  14. Avenanthramides Unique to oats Mainly bran constituents Not related to the oil content

  15. Tranilast Metabolites Tranilast Oat avenanthramide

  16. Supression of vascular stenosis by Tranilast Control Tranilast Fukuyama et. al. 1996. European Journal of Pharmacology, 318, 327-332

  17. Avenanthramides-effects of processing- Storage stable in whole grains Instable in raw oat flour soaked in water Heat stable Increase during germination

  18. Effect of germination

  19. Avenanthramides-effects of cultivation measures- Developmental stage Susceptible/Resistance Genotype/Site/Year Nitrogen/Light/Irrigation Conventional /Organic Farming

  20. Avenanthramides-the same variety different year-

  21. Concluding remarks • Whole grain vs flour • Processing • Bioavalability Flour Groats

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