Unambiguous detection of astaxanthin and astaxanthin fatty acid esters in krill (Euphausia superba Dana)

Abstract

HPLC atmospheric pressure chemical ionization (APCI)/MS, GC MS, HPLC diode array detection (DAD), and NMR were used for the identification of astaxanthin and astaxanthin fatty acid esters in krill (Euphausia superba Dana). Matrix solid phase dispersion was applied for the extraction of the carotenoids. This gentle and expeditious extraction technique for solid and viscous samples leads to distinct higher enrichment rates than the conventional liquid-liquid extraction. The chromatographic separation was achieved employing a C30 RP column that allows the separation of shape-constrained geometrical isomers. A methanol/tert-butylmethyl ether/water gradient was applied. (all-E) Astaxanthin and the geometrical isomers were identified by HPLC APCI/MS, by coelution with isomerized authentical standard, by UV spectroscopy (DAD), and three isomers were unambiguously assigned by microcoil NMR spectroscopy. In this method, microcoils are transversally aligned to the magnetic field and have an increased sensitivity compared to the conventional double-saddle Helmholtz coils, thus enabling the measurement on small samples. The carotenol fatty acid esters were saponified enzymatically with Lipase type VII from Candida rugosa. The fatty acids were detected by GC MS after transesterification, but also without previous derivatization by HPLC APCI/MS. C14:0, C16:0, C16:1, C18:1, C20:0, C20:5, and C22:6 were found in astaxanthin monoesters and in astaxanthin diesters. (all-E) Astaxanthin was identified as the main isomer in six fatty acid ester fractions by NMR. Quantitation was carried out by the method of internal standard. (13-cis) Astaxanthin (70 microg/g), 542 microg/g (all-E) astaxanthin, 36 microg/g unidentified astaxanthin isomer, 62 microg/g (9-cis) astaxanthin, and 7842 microg/g astaxanthin fatty acid esters were found.

Effect of Thermal Processing on Astaxanthin and Astaxanthin Esters in Pacific White Shrimp <i>Litopenaeus v</i><i>annamei</i>

“…Interestingly, C12:0, and C14:0, which is abundant in total lipids of Pacific white shrimp 28 and other shrimp species reported previously 12 , was not identified in astaxanthin esters. In contrast to krill 13 , red crab langostilla 29 and arctic shrimp 12 , the fatty acid profile of astaxanthin esters in Pacific white shrimp is typical with higher content of PUFAs and both presence in the fraction of astaxanthin monoester and diesters. 3.2 Effects of thermal processing on total astaxanthin content in Paci c white shrimps The study investigated the stability as well as degradation of free astaxanthin and astaxanthin esters in Pacific white shrimps during common thermal processing.…”

Photoprotective compounds from marine organisms

“…One or both ends of the carbon skeleton may go through cyclization to form ring b-ionone ring end groups, which additionally may be substituted by oxo, hydroxy or epoxy groups at dissimilar positions to form the different xanthophylls [197]. About 600 different carotenoids have been identified from different organisms such as cyanobacteria, bacteria, fungi, phytoplankton, macroalgae, plants and animals [43, 82,158]. Animals lack the ability to synthesize carotenoids endogenously and thus have to take up these compounds by means of their diet [140].…”

Epoxycarotenoids esters analysis in intact orange juices using two‐dimensional comprehensive liquid chromatography

“…2A. C 30 stationary phase columns have been used to study the carotenoid esters composition of several matrices, such as pumpkins and apricots [13], plant extracts [35], marigold flowers [36] and other chinese herbs [37], krill [38], paprika [39] and mango [40] among others [41,42]. However, most of these works were aimed only to a class of carotenoid esters such as zeaxanthin esters [35].…”