Comparing DPPP fluorescence and UV based methods to assess oxidation degree of krill oil-in-water emulsions

In this study, lipid oxidation evaluation methods were compared for a krill-oil-in-water emulsion system. With this aim, thiocyanate and DPPP (diphenyl-1-pyrenylphosphine) fluorescence methods were comparatively examined to determine primary oxidation products. 2-thiobarbituric acid reactive substances (TBARS), hexanal and propanal formation were also monitored as secondary oxidations products. All oxidation experiments were performed via both auto-oxidation at 45 degrees C and light-riboflavin induced photooxidation at 37 degrees C. The results have shown that thiocyanate method was not suitable to measure lipid hydroperoxides by the both in auto- and photo-oxidation systems. On the other hand, fluorescence intensity of samples containing the DPPP probe increased during incubation period which indicates the formation of lipid hydroperoxides could be detected via this method. TBARS, hexanal and propanal concentrations also increased during storage period and the formation kinetics of secondary oxidation products was confirmed that the DPPP fluorescence method was accurate and reliable at different environmental conditions.

Automated summary

This study compared two lipid oxidation evaluation methods in a krill-oil-in-water emulsion system, finding that the thiocyanate method was not suitable for measuring lipid hydroperoxides, while the DPPP fluorescence method was accurate and reliable in detecting their formation. Additionally, secondary oxidation products such as TBARS, hexanal, and propanal concentrations were monitored and their formation kinetics confirmed the efficacy of the DPPP fluorescence method under different environmental conditions.