Effect of temperature towards lipid oxidation and non-enzymatic browning reactions in krill oil upon storage

• The increase of incubation temperature increased the lipid oxidation in krill oil.
• The increment of lipid oxidation could increase non-enzymatic browning reactions.
• Strecker degradation products were formed in oxidised krill oil.
• Pyrazines and pyridines were formed when carbonyls reacted with amino acids.
• Pyrroles may protect krill oil against lipid oxidation during incubation.

The main objective of this study was to investigate the effect of temperature towards lipid oxidation and non-enzymatic browning reactions in krill oil upon storage. Krill oil was incubated at two different temperatures (20 and 40 °C) for 28 or 42 days. The oxidative stability of krill oil was assessed by peroxide value and anisidine value, measurement of lipid derived volatiles, lipid classes and antioxidants. The non-enzymatic browning reactions were assessed through the measurement of pyrroles, free amino acids content and Strecker-derived volatiles. The increase of incubation temperature firstly increased the lipid oxidation in krill oil and subsequently the non-enzymatic browning reactions. The occurrence of these reactions was most likely due to the reaction between α-dicarbonyl or carbonyl compounds with amino acids or ammonia. In addition to tocopherol and astaxanthin esters, the formation of pyrroles might help to protect the krill oil against lipid oxidation.