RESUMO
Cyanobacteria and microalgae are characterized by a rich and varied profile of chlorophyll (8-20 mg/g) and carotenoid (>2.2 mg/g) pigments, being noteworthy material for natural pigment production in the food industry. We propose a systematic workflow that uses high-performance liquid chromatography (HPLC) coupled with high-resolution tandem mass spectrometry in a broadband collision-induced dissociation mode (bbCID) acquisition mode to simultaneously obtain MS and MSn spectra. Metabolomic studies showed for the first time the presence of carotenoids with 5,6-epoxy-groups (5,6-epoxy- and 5,8-furanoid ß-cryptoxanthin), carotenoids from the α-branch (5,8-furanoid-2'-3'-didehydro α-cryptoxanthin), and 2'-dehydrodeoxomyxol in cyanobacteria. To support the new findings, an in silico search retrieved the putative sequences of carotenogenic enzymes involved in the corresponding biosynthetic pathways (ZEP, NSY, CrtL-b and CrtR) in the analyzed cyanobacteria species. Consequently, high-throughput metabolomics studies assisted by molecular analysis offer a powerful tool for providing insights into the characterization of bioactive compounds and their metabolism in cyanobacteria and microalgae.
Assuntos
Carotenoides/metabolismo , Cianobactérias/metabolismo , Vias Biossintéticas , Carotenoides/química , Cromatografia Líquida de Alta Pressão , Criptoxantinas/análise , Criptoxantinas/metabolismo , Cianobactérias/química , Metabolômica , Espectrometria de Massas em TandemRESUMO
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.