Abstract:

The controversial topic of synthetic dyes in food has been discussed for many years. The negative assessment of synthetic food dyes by themodern consumer have raised a strong interest in natural colouring alternatives. Carotenoids are natural pigments responsible for colors ranging fromyellow through orange to red, and are biosynthesized in all photosynthetic organisms, including cyanobacteria, photosynthetic bacteria belonging toAlphaproteobacteria, algae, and higher plants, and also in some non-photosynthetic bacteria, yeasts, and fungi. Several carotenoid pigments havebeen used commercially as food colorants and as animal feed additives in poultry farming and aquaculture. Therefore, carotenoids are also beingused for cosmetic properties. Carotenoids are pigments which play a major role in the protection of plants against photooxidative processes. In thehuman organism, carotenoids are part of the antioxidant defense system. In photosynthetic organisms, in addition to ligth harvesting, they performan essential role in protecting against light-induced damage by quenching singlet oxygen, superoxide anion radicals, or triplet-state chlorophyll. Inthese cyanobacteria, various carotenoids have been identified. A photoprotective role has also been suggested for carotenoids in non-photosyntheticbacteria. This review provides an overview of microbial carotenoids.

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