The incorporation of bioactive compounds into fruit juices is limited by their instability and interactions with the food matrix. Encapsulation may help preserve their functionality and improve beverage stability.

Materials and Methods: This study investigated the effects of free and nanoliposome-encapsulated olive kernel protein hydrolysate on the physicochemical properties of bitter orange juice during 30 days of storage at 4°C. Hydrolysate solution (20 mg/mL) was added at 2% and 4% (v/v) in free or encapsulated form. DPPH radical scavenging activity, browning index, cloudiness, phase separation, and color parameters were evaluated every 10 days.

DPPH radical scavenging activity decreased in all treatments during storage. However, the 4% encapsulated treatment retained higher activity, decreasing from 93.2 ± 5.8% on day 10 to 87.9 ± 5.7% on day 30, compared with a decrease from 78.6 ± 5.5% to 52.6 ± 5.2% in the control. The control browning index increased from 0.565 ± 0.06 to 0.692 ± 0.07, whereas the lowest values were observed in the 2% encapsulated treatment (0.403 ± 0.04 to 0.476 ± 0.05). Phase separation in the control increased from 46.25 ± 0.5% to 50.37 ± 0.65%, compared with 34.25 ± 0.3% to 37.84 ± 0.3% in the 4% encapsulated treatment. Cloudiness increased in all treatments and was highest in the 4% encapsulated treatment. Encapsulated samples also exhibited greater lightness and yellowness than samples containing free hydrolysate.

Nanoliposome encapsulation, particularly at 4%, improved antioxidant retention and reduced browning and phase separation, indicating its potential for developing more stable functional fruit beverages.