The Color of Lobsters

Abstract

Synthesis of 13C-enriched carotenoids. Carotenoids are natural colorants, ranging in color from pale yellow to deep purple, with important biological functions. Carotenoids in the human diet have a beneficial health effect, playing a role in the prevention of cardiovascular disease and cancer. To get more insight in the beneficial health effects of carotenoids, sensitive and accurate analysis is essential. The combination of 13C-enrichment of carotenoids and isotope-sensitive analysis allows the determination of small amounts of metabolites in the human body. To obtain the required 13C-enriched carotenoids, the development of efficient synthetic routes is described in this thesis. The color of lobsters. In nature, many carotenoids are bound to proteins, to form carotenoproteins. Often this binding is accompanied by a remarkable change in color, as the example of the carotenoprotein that is responsible for the deep blue color of the lobster shell. When the lobster is cooked, the protein denatures and the red carotenoid is released, which gives the lobster it__s striking red color after cooking. To understand this color change, 13C-enriched carotenoid was made and bound in the lobster protein. Using a combination of isotope-sensitive analyses and computational methods, we found that the color change is predominantly caused by intermolecular interactions between the carotenoids that are in close proximity when bound in the protein.