RESUMEN
Among the nutritional properties of microalgae, this study is focused in the presence of carotenoid esters in prokaryote microalgae, an event that has not been shown so far. Three carotenoid esters that accumulate in non-stressful culture conditions are identified in Aphanotece microscopica Nägeli and Phormidum autumnale Gomont, what may provide an extra value to the quality attributes of the carotenoid profile in cyanobacteria as functional foods. In addition, new data on the carotenoid characterization added quality criteria for the identification of the esterified metabolites, enabling the monitoring of these food components. Specifically, the metabolomic approach applied to the food composition analysis, has allowed to differentiate between the esters of zeinoxanthin and ß-cryptoxanthin, which were undifferentiated to date during the MS characterization of carotenoids in other food sources. We propose a new qualifier product ion specific for zeinoxanthin ester, which it is not present in the MS2 spectrum of ß-cryptoxanthin esters.