Milk Fat Globules Protect Exogenously Infused Docosahexaenoic Acid-Derived Oxylipins at Low pH Conditions.

Oxylipins derived from the enzymatic oxidation of omega-3 docosahexaenoic acid (DHA) are known to promote the resolution of inflammation in vivo. Although these bioactive lipids are enriched in seafood, they are thought to be unstable when ingested due to the low pH of the stomach. Previously, we discovered that milk fat globules (MFGs) can be used to encapsulate and stabilize food bioactives such as curcumin and vitamin D. In the present study, we tested the hypothesis that infusion of DHA-derived 16(17)-epoxydocosapentaenoic acid (16(17)-EpDPE) and 17-Hydroxydocosahexaenoic acid (17-HDoHE) into a natural encapsulation system of MFGs, would stabilize these oxylipins at low pH mimicking gastric conditions. In preliminary experiments, we first optimized the partitioning of 16(17)-EpDPE and 17-HDoHE into MFGs and then tested their stability with or without encapsulation into MFGs at pH 2 and 7. We found that 16(17)-EpDPE and 17-HDoHE were rapidly incorporated into MFGs, with approximately 50% of the added concentration being encapsulated within 30 min of incubation. Oxylipins encapsulated into MFGs were protected for up to 2 h of incubation at pH 2 and 7, whereas non-encapsulated oxylipins degraded rapidly at either pHs. These results show that MFGs can stabilize and protect DHA-derived oxylipins during in vitro conditions mimicking stomach pH, highlighting their potential to serve as carriers for delivering oxylipins in vivo. PRACTICAL APPLICATIONS: Oxylipins are a class of bioactive lipid mediators present in oils and foods that are thought to degrade under low pH stomach conditions. The study provides evidence that milk fat globules (MFGs) protect oxylipins from degradation under low pH conditions in vitro. The findings show that MFGs can be used to stabilize and potentially enhance the delivery of oxylipins, particularly those involved in anti-inflammatory and pro-resolving activities in vivo.