CHAPTER 8: Extraction and Cleanup of Xanthophyll Esters

Carotenoids are naturally found in both free forms and esterified with fatty acids in many fruits, flowers, animals, microorganisms and algae. The interest in knowing the naturally occurring composition of carotenoids in food, which includes their esterified form, has grown in recent years. However, as the native carotenoid composition is complex, it is often disregarded in several studies, since saponification is routinely done for carotenoid analyses in order to hydrolyse esters and remove interferers, specifically triacylglycerides and chlorophylls. Several methods have been developed for the extraction of carotenoid esters, but they are often very similar to the methods for the extraction of carotenoids in their free form, except for the saponification step. Due to the presence of interferers in the carotenoid ester extracts, their removal can be carried out via a cleaning step. For this purpose, the main applied techniques are physical separation, chromatographic columns and lipases capable of hydrolysing triacylglycerides and keeping the xanthophyll esters intact. Recently, the use of green solvents modernised the extraction process in order to generate products with less toxic waste, making this process more environmentally sustainable.