Carotenoids

1. Carotenoids • Jaromír Kupka, Vladimír Ondruška

2. Introduction • Nature’s widespread pigments • biosynthese by ocean algae • masked by dominant chlorophyll • fotosynthesis and photoprotection • ability inactivate reactive oxygen • precursors of vitamin A

3. Introduction • Provitamin A presents 30 -100 % of the vitamin A requirement • retinoid structure  vitamin A activity

4. Hydrocarbons carotenes Oxygenated xanthophylls Structures of carotenoids I Two groups of structure

5. Structures of carotenoids II • groups on xantophylls: • hydroxyl, epoxy, aldehyde and keto • isoprene unit = basic structure

6. Some types ofcarotenoids

7. Occurrence and distribution • Fruit and vegetables: • Tomatoes (lycopene) • Carrots (-, -carotenes) • Red peppers (capsanthin) • Pumpkins (-carotene) • Sweet potatoes (-carotene)

8. Occurrence and distribution • All green vegetables contain carotenoids but their color is masked by the green chlorophylls

9. Physical properties • All carotenoids are lipophilic compounds and thus are soluble in oils and organic solvents • they can be isomerized by heat, acid, light • many carotenoids exhibit spectral shifts with various reagents and these spectral changes are used for identification

10. Chemical properties • Carotenoids are easily oxidized because of large number of conjugated double bonds • Such reactions cause color loss of carotenoids in foods • Destability of a particular pigment to oxidation is highly dependent on its environment

11. Vocabulary • Algae - řasy • dependent - závislý • storage - skladování • spectral shift - • spekt. přechod • susceptibility - citlivost

12. Thank you for your attention