Abstract

In this study, curcumin and red palm oil (which is rich in carotenoids and tocotrienols) were co-encapsulated in nanoliposomes assembled from egg yolk phospholipids. These nutraceutical-loaded nanoliposomes were then used to fortify dairy yogurts. The yogurts were evaluated for physicochemical properties, bioactive retention, antioxidant activity, oxidative stability, microstructure, microbial safety, and sensory quality during 14 days of refrigerated storage. Fourier transform infrared spectroscopy analysis confirmed that the nutraceuticals were successfully incorporated into the yogurt matrix. The pH, titratable acidity, viscosity, syneresis, and color analyses indicated that fortification caused some changes in the physicochemical attributes of the yogurts. The fortified yogurts had significantly increased β-carotene (10.8–14.8 mg/100 g) and curcumin (0.26–0.58 mg/100 g) contents. During refrigerated storage, the degradation of β-carotene and curcumin followed first-order kinetics (R2 = 0.84–0.99), and yogurt fortified with 3 % nanoliposomes exhibited the lowest degradation rate constants, indicating superior storage stability. Moreover, the antioxidant capacity was also improved, with DPPH inhibition rising to 27.7 %–36.2 % and ABTS inhibition rising to 23.1 % –27.1 %. Fortification reduced syneresis and imparted a desirable yellowish appearance. In addition, the fortified yogurts showed favorable texture and had the highest sensory scores, suggesting an optimal balance of quality and functionality. Total plate counts of all samples remained at least 5.39 log CFU/g, which is within acceptable levels for yogurt. Sensory evaluation indicated a slight decline in flavor and overall acceptability compared to the control, but the values still remained within the acceptable range. Overall, these findings demonstrate that fortification with curcumin/red palm oil-loaded nanoliposomes can enhance the bioactive content and antioxidant properties of dairy yogurt while maintaining acceptable quality attributes. Yogurt fortified with 3 % nanoliposomes offered the best balance between functional benefits and product quality and is therefore recommended as the optimal fortification level for practical use.