Due to the fact that association colloids were formed in krill oil, the oxidation mechanism of krill oil was more complicated. In this study, water-soluble ferrous sulfate (Fe 2 (SO 4 ) 3 ), oil-soluble ferrous fumarate (C 54 H 99 FeO 6 ) and insoluble ferric oxide (Fe 3 O 4 ) were added to krill oil and stored at 60 °C for accelerated oxidation. Peroxide value, thiobarbituric acid reactive substances and aldehyde content showed that Fe 2 (SO 4 ) 3 had a stronger pro-oxidative effect. This was caused by the fact that water-soluble Fe 3+ was mainly accumulated in extremely high content at oil-water interface of association colloids. In contrast, oil-soluble C 54 H 99 FeO 6 was mainly distributed in the oil phase. Lipidomic analysis revealed that, phospholipids were rapidly catalytically decomposed by water-soluble Fe 3+ at the oil-water interface and produced lipid hydroperoxides and free radicals. Subsequently, the produced free radicals could enter the oil phase and set off a chain reaction of free radical formation, and then promote the oxidation of glycerides.
Antarctic krill (Euphausia superba) oil contains high levels of marine omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In industrial production, krill oil is usually extracted from krill meals by using ethanol as a solvent. Water in the krill meal can be easily extracted by using ethanol as an extraction solvent. During the extraction process, the EPA and DHA are more easily oxidized and degraded when water exists in the ethanol extract of krill oil. Based on the analysis of peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), fatty acid composition, and lipid class composition, the present study indicated that the composite antioxidants (TP-TPP) consist of tea polyphenol (TP) and tea polyphenol palmitate (TPP) had an excellent antioxidant effect. By contrast, adding TP-TPP into ethanol solvent during the extraction process is more effective than adding TP-TPP into krill oil after the extraction process.Keywords:antarctic krill;oil;antioxidant;tea polyphenol;composite antioxidants;ethanol
This study investigates the role of ferrous ion partitioning in promoting lipid oxidation in Antarctic krill oil (AKO) containing reverse micelles. Cryogenic transmission electron microscopy and small-angle X-ray scattering confirmed the presence of reverse micelles in AKO. AKO with ferrous sulfate (FeSO 4 , water-soluble iron) and ferrous fumarate (C 4 H 2 FeO 4 , oil-soluble iron) were stored at 60 °C. Interestingly, compared with oil-soluble Fe 2+ , water-soluble Fe 2+ significantly enhanced oxidation. Confocal laser scanning microscopy (CLSM) showed that water-soluble Fe 2+ and lipid hydroperoxides (LOOHs) concentrated at the oil-water interface of reverse micelles, whereas ferrous fumarate was distributed in the oil phase. Meanwhile, water-soluble Fe 2+ significantly promote the oxidation of phospholipids at the oil-water interface, leading to the formation of LOOHs and free radicals that entered the oil phase, triggering glyceride oxidation. Overall, this characterization of the spatial distribution and pro-oxidant effects of metal ions in AKO provides valuable insights into the development of novel antioxidant technologies.
危险品化学品经营许可证（带存储）