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 mu g g(-1), r(2) (p) = 0.98) quantitate astaxanthin in krill oil despite its low concentrations (212-693 mu g g(-1)). This analysis could be performed directly through gelatin capsules with no loss of prediction accuracy (RMSEP = 27 mu g g(-1), r(2) (p) = 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%, r2 p = 0.99) than models from either Raman (RMSEP = 4.5%, r(2) (p) = 0.90) or IR (RMSEP = 7.3%, r(2) (p) = 0.73). Data fusion also significantly improved quantitation accuracy for quantification of other fatty acid classes.

Automated summary

Krill oil contains essential long-chain omega-3 polyunsaturated fatty acids EPA and DHA, as well as the keto-carotenoid astaxanthin. Raman spectroscopy proved effective in accurately quantifying astaxanthin in krill oil, while the fusion of IR and Raman data did not improve the quantification models. Mid-level fusion was found to provide more accurate quantification of EPA+DHA compared to standalone Raman or IR spectroscopy.