Raman and Infrared Spectroscopic Data Fusion Strategies for Rapid, Multicomponent Quantitation of Krill Oil Compositions

Krill oil contains eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), long chain omega-3 polyunsaturated fatty acids with essential roles in human health, and astaxanthin, a naturally occurring keto-carotenoid that protects EPA+DHA against oxidation. Here, we assess Raman and IR spectroscopy (as stand-alone techniques and paired using three different data-fusion approaches) as methods for simultaneous quantitation of EPA+DHA and astaxanthin in krill oil. Raman spectroscopy could accurately (RMSEP = 40 μg g-1, r2p = 0.98) quantitate astaxanthin in krill oil despite its low concentrations (212-693 μg g-1). This analysis could be performed directly through gelatin capsules with no loss of prediction accuracy (RMSEP = 27 μg g-1, r2p = 0.99). Fusing IR and Raman data did not improve the astaxanthin quantitation models. EPA+DHA quantitation was more accurate using “mid-level” fusion (RMSEP = 1.2%, r2p = 0.99) than models from either Raman (RMSEP = 4.5%, r2p = 0.90) or IR (RMSEP = 7.3%, r2p = 0.73). Data fusion also significantly improved quantitation accuracy for quantification of other fatty acid classes.