Carotenoids can be found in nature mostly as long-chain fatty acid esters; thus, chemical synthesis of these esters may be necessary for the carotenoid analysis of plant samples. From the synthetic point of view, the saponified carotenoids are typically used, and their functional groups are modified. Another field of ester synthesis is the attachment of hydrophilic moieties to hydroxy-carotenoids (i.e. xanthophylls containing hydroxyl functional groups) to improve their bioavailability, as well as their antioxidant and pharmacological properties. Esterification is considered to be a mild method in support of the conjugation of carotenoids with other bioactive compounds.