Study on the improvement of the oxidative stability of DHA and FPA

多不饱和脂肪酸（PUFAs）的氧化稳定性随着不饱和程度的增加而降低。然而，PUFAs在水溶液中的氧化稳定性与纯相有很大不同，其中22:6 n-3氧化稳定性最好，其次是20:5 n-3、20:4 n-6、18:3 n-3、18:3 n-6和18:2 n-6。在三酰甘油（TGs）和磷脂酰胆碱（PCs）的水氧化中也观察到同样的趋势。金枪鱼眼眶脂肪中的TG比豆油中的TG在空气中更容易被氧化，然而，前者在乳剂中比后者更具氧化稳定性。在水溶液中，鲑鱼蛋PC的氧化稳定性也高于大豆PC，但鲑鱼蛋PC的平均不饱和程度高于大豆PC。多不饱和脂质在水溶液中的氧化稳定性可能与脂质分子的构象和/或脂质聚集的性质有关。本研究结果对于了解生物系统中多不饱和脂的氧化稳定性具有重要意义，并表明通过将鱼油分散在水溶液中来保护鱼油免受氧化的可能性。

The oxidative stability of polyunsaturated fatty acids (PUFAs) decreases with their increasing degree of unsaturation.However, the oxidative stability of PUFAs in an aqueous solution was quite different from that in the neat phase, and 22 : 6n-3 was most oxidatively stable, followed by 20 : 5n-3,20 : 4n-6,18 : 3n-3,18 : 3n-6, and 18 : 2n-6, each in an aqueous phase.The same tendency was observed in the aqueous oxidation of triacylglycerols (TGs) and phosphatidylcholines (PCs).TG from orbital fat of a tuna was more susceptible to oxidation than soybean oil TG in the air, however, the former became oxidatively more stable than the latter in an emulsion.Salmon egg PC was also more stable to oxidation than soybean PC in an aqueous soution, although the average degree of unsaturation of salmon egg PC was higher than that of soybean PC.The characteristic oxidative stability of polyunsaturated lipids in an aqueous solution may be correlated with the conformation of the lipid molecule and/or the nature of lipid aggregation.The present findings will be important for undestanding the oxidative stability of polyunsaturated lipids in a biological systems and show the possibility of protection of fish oils from their oxidations by dispersing them in an aqueous solution.