Encapsulation of ferulic acid ethyl ester in caseinate to suppress off-flavor formation in UHT milk

• Lipophilic ferulic acid ethyl ester (FAEE) was encapsulated in caseinate by spray drying.
• Physicochemical stabilities of the encapsulated FAEE (enFAEE) were excellent after UV radiation.
• The enFAEE also showed excellent stabilities after heating at 138 °C for 16 min.
• The enFAEE suppressed the formation of 2-acetyl-2-thiazoline in model UHT milk.
• The antioxidant property of enFAEE resulted in the suppression of off-flavor formation.

Phenolic compounds can principally suppress the off-flavor development in ultrahigh temperature (UHT) treated milk, but little has been studied for lipophilic phenolic compounds that are to be encapsulated for even distribution in milk. The objective of this work was to study physicochemical properties of ferulic acid ethyl ester (FAEE) encapsulated in sodium caseinate and the inhibition of volatile formation after UHT processing. The capsules had an average hydrodynamic diameter of 246.2 ± 10.9 nm, a polydispersity index of 0.26 ± 0.01, and a zeta-potential of −31.72 ± 0.74 mV. The capsules and the encapsulated FAEE were stable after heating at 138 °C for 16 min and UV radiation at 365 nm for 32 h. The encapsulated FAEE at a level of 0.18–1.42 mg/mL suppressed the formation of 2-acetyl-2-thiazoline in model UHT milk by 32.8–63.2% after 30-day storage at 30 °C. Therefore, FAEE encapsulated in caseinate can be potentially used to improve the quality of UHT milk.