Liposomal Encapsulation of Damson Plum Phenolics and Their Incorporation Into Functional Milk Beverages

ABSTRACT

This study assessed liposomal strategies for the delivery of New Zealand damson plum extract (DPE) phenolics into a functional milk beverage and preserving their stability during refrigerated storage. Liposomes were manufactured by high‐shear mixing (HSM) with or without microfluidization (MF), and their properties were evaluated before and after freeze‑drying (FD‑HSM, FD‑HSM+MF). Incorporation of DPE‑loaded liposomes increased milk total solids (8.80%) relative to the control (8.16%) without measurably altering viscosity, indicating maintained flow behavior. However, freeze‑dried (FD) liposomal systems increased the apparent particle size in milk (800.5 ± 72.1 nm), compared with non‑FD systems/control (375 ± 13.7 nm), and reduced pH to 5.17, highlighting formulation constraints associated with acidification and colloidal stability. Despite these matrix effects, phenolic recovery in FD liposomal milk was high, with neochlorogenic acid, rutin, and rosmarinic acid reaching 98.86%, 94.69%, and 96.00%, respectively. Following 28 days of refrigerated storage (4°C), FD‑HSM+MF provided the greatest preservation of phenolics after incorporation into milk, demonstrating that combining MF with freeze‑drying can enhance phenolic retention in dairy beverages. Accordingly, microfluidized freeze‑dried liposomes represent a scalable route for phenolic fortification of milk, provided pH and physical stability are appropriately managed. Taken together, this work offers a process‐ready encapsulation solution for improving phenolic delivery and stability in milk, an essential step toward commercially viable functional dairy beverages.