123159-02-4

Upstream product

• 7542-45-2 3,3'-dihydroxy-β,β-carotene-4,4'-dione 
• 112-67-4 n-hexadecanoyl chloride 
• 112421-21-3 astaxanthin dipalmitate 

Relevant academic research and scientific papers

Fatty acid selectivity of microbial lipase and lipolytic enzymes from salmonid fish intestines toward astaxanthin diesters

The objective of the work described in this paper was to study a possible FA selectivity of digestive lipolytic enzymes isolated from salmon and trout intestines toward astaxanthin diesters of various FA composition and compare it with the FA selectivity of microbial lipase. Astaxanthin diesters of varying FA composition were prepared in excellent yields (>90%) by chemical esterification using a carbodiimide coupling agent. The astaxanthin diesters were screened in a hydrolysis reaction by various commercially available lipases. The highest conversion rates were observed with the Candida rugosa lipase, which discriminated against n-3 PUFA. The rate of hydrolysis was determined by HPLC. Digestive lipolytic enzymes isolated from salmon and rainbow trout intestines displayed reversed FA selectivity. Thus, astaxanthin diesters highly enriched with n-3 PUFA including EPA and DHA were observed to be hydrolyzed at a considerably higher rate than the more saturated esters. Similar trends in FA selectivity were observed in the hydrolysis of fish oil TAG by the digestive lipolytic enzyme mixtures.

Identification and quantification of astaxanthin esters in shrimp (Pandalus, borealis) and in a microalga (Haematococcus pluvialis) by liquid chromatography-mass spectrometry using negative ion atmospheric pressure chemical ionization

Negative ion liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [negative ion LC-(APCI)MS] was used for the identification of astaxanthin esters in extracts of commercial shrimp (Pandalus borealis) and dried microalga (Haematococcus pluvialis) samples. A cleanup step using a normal phase solid phase extraction (SPE) cartridge was applied prior to analysis. Recovery experiments with astaxanthin oleate as model compound proved the applicability of this step (98.5 ± 7.6%; n = 4). The assignment of astaxanthin esters in negative ion LC-(APCI)MS was based on the detection of the molecular ion (M.-) and the formation of characteristic fragment ions, resulting from the loss of one or two fatty acids. Quantification of individual astaxanthin esters was performed using an astaxanthin calibration curve, which was found to be linear over the required range (1-51 μmol/L; r2 = 0.9996). Detection limits, based on the intensity of M.-, a signal-to-noise ratio of 3:1, and an injection volume of 20 μL, were estimated to be 0.05 μg/mL (free astaxanthin), 0.28 μg/mL (astaxanthin-C16:0), and 0.78 μg/mL (astaxanthin-C16:0/C16:0), respectively. This LC-(APCI)MS method allows for the first time the characterization of native astaxanthin esters in P. borealis and H. pluvialis without using time-consuming isolation steps with subsequent gas chromatographic analyses of fatty acid methyl esters. The results suggest that the pattern of astaxanthin-bound polyunsaturated fatty acids of P. borealis does not reflect the respective fatty acid pattern found in triacylglycerides. Application of the presented LC-(APCI)MS technique in common astaxanthin ester analysis will forestall erroneous xanthophyll ester assignment in natural sources.