Studies into carotenoid deposition forms in plants and nutraceutical formulations with special reference to their influence on carotenoid bioavailability

The present doctoral thesis has unraveled the occurrence of different carotenoid deposition forms in plant sources, such as the lipid-dissolved forms in peach palm fruit, the liquid-crystalline forms in goji berries, and the potentially microcrystalline forms in gac fruit aril. Novel insights regarding the underlying fundamental principles of carotenoid aggregation were gained when studying the aggregation of naturally occurring and nutritionally relevant carotenoids with specific structural features. The importance of a better understanding of natural and technologically-producible aggregate forms of carotenoids was finally demonstrated by a human clinical trial on the bioavailability of differently aggregated carotenoids, showing that zeaxanthin was more bioavailable from a J-aggregated zeaxanthin dipalmitate formulation than from an H-aggregated zeaxanthin formulation. As differently aggregated carotenoid forms also naturally occur in carotenoid-rich plant and animal foods as well as in nutraceutical formulations, a deeper understanding of the key factors governing the bioavailability of the contained carotenoids will support future nutritional evaluations and recommendations.