SEASONAL VARIATION OF LIPID AND CAROTENOID CONTENT OF CUCUMARIA FRONDOSA VISCERA OIL AND THE DEVELOPMENT OF METHODS FOR ITS QUALITY CONTROL

Abstract

Little is known about the lipids and carotenoids of the lipid extracted from sea cucumber viscera (SCV) of Cucumaria frondosa, the species harvested from Nova Scotia, Canada. Tons of SCV are discarded as a waste stream from the processing of sea cucumber for its body wall and muscle bands, which have market value. The aim of this project was to characterize the lipid extracted from C. frondosa’s viscera in terms of lipid class, FA and carotenoid composition and to examine the seasonal variation in these components. Lipid class analysis of sea cucumber viscera lipid (SCVL) indicated the presence of phospholipids (PL), TAG and ether lipids (diacylglyceryl ethers (DAGE) and monoacyglyceryl ethers (MAGE)). FFA, MAG, and DAG were detected in trace amounts. The proportions of lipid classes were found to vary with season with highest proportions of DAGE in winter and spring harvests (~50 % and ~40 % of total recovered lipids respectively). TAG represented ~45 % of total recovered lipids in the summer harvest. SCVL was a rich source of PUFA (29-32 % by mass FA), in particular EPA that was associated mostly with PL (> 30 %) and MAGE (> 45 %) in the winter harvest. SCVL contained 12-methyltetradecanoic acid (12-MTA), a branched fatty acid (BCFA) that exhibits anticancer activity and has been used in drug development studies. 12-MTA was associated mostly with DAGE and represented about 50 % of the total mass of FA in the winter harvest. Carotenoids in this extract occur at levels of 1.5-2.5 mg/g of the lipid extract as determined using a UV spectrophotometric method. Astaxanthin and canthaxanthin comprised 146 μg/g and 650-730 μg/g of lipid extract, respectively. The winter harvest exhibited the highest levels of lipid and carotenoid content, PUFA, EPA, 12-MTA, and BCFA when compared to spring and summer harvests. Finally, to determine the stability of the highly pigmented SCVL, a spectrophotometric method using FOX was adapted and validated to measure accurate peroxide values (PV) of SCVL. The method was linear, accurate, precise and applicable, and reduced the interference of the carotenoids in the measurement of PV of SCVL.