Date of Award

Fall 12-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Food Science

First Advisor

John Miklavcic

Second Advisor

Anuradha Prakash

Third Advisor

Rosalee Hellberg

Abstract

Background. Extracellular vesicles (EVs) are membrane-bound nanostructures released by human and bovine mammary epithelial cells that carry bioactive lipids and oxidized lipid metabolites. Found in bovine milk, EVs contribute to immune modulation, gut health, and cellular signaling. However, gaps remain in understanding the full composition of milk-derived EVs and how processing alters EV content. This research aimed to characterize the free oxylipin content of EVs from bovine milk treated by pasteurization and homogenization. The hypothesis was that EVs from raw bovine milk would retain higher oxylipin levels than processed milk. Methods. Raw milk was treated by high-temperature short time (HTST), homogenized hightemperature short time (HgHTST), low temperature (LT), or homogenized low temperature (HgLT). Milk was defatted, and the aqueous fraction underwent ultracentrifugation to isolate EVs. Protein content was assessed using a Qubit 4 fluorometer, and oxylipin analysis by LC/MS. Descriptive statistics and nonparametric testing compared oxylipin levels across treatments. Results. Twelve oxylipins were detected in bovine milk and EVs. 9-HODE (!2 =0.92) and 15- HEPE (!2=0.91) were highly correlated between EVs and whole milk. 13-HODE decreased by 69% in HTST (p=0.031) compared to the reference. Levels of 17-HDHA and 17(18)-DiHETE were significantly (p < 0.05) different across treatments compared to the reference. Discussion. Oxylipin content of bovine milk EVs is measurable and correlates strongly with whole milk. Processing lowered oxylipin content, emphasizing that heat and homogenization alter bioactive lipid metabolites and EV function. This knowledge may inform future infant nutrition initiatives using EVs as bioactives.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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Available for download on Friday, December 19, 2025

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