Document Type : Research Article
Authors
1
Department of Food Science and Technology, Gorgan Branch, Islamic Azad University, Gorgan, Iran
2
Department of Food Science and Technology, Faculty of Agriculture, University of Jiroft, Jiroft, Iran
10.22067/ifstrj.2026.99705.1600
Abstract
Green tea extract (GTE) and Moringa oleifera extract (MOE) are rich sources of phenolic compounds with strong antioxidant properties; however, their direct addition to drinkable yogurt is accompanied by challenges such as bitter and astringent taste, instability of phenolic compounds, and reduced sensory acceptance. In this study, these extracts were microencapsulated using spray drying with maltodextrin and gum arabic (1:1 ratio) as wall materials. The produced microcapsules were evaluated for encapsulation efficiency, particle size, moisture content, water activity, and morphology (SEM). The encapsulated powders were then added to drinkable yogurt individually and in combination (1:1 ratio), and the physicochemical, antioxidant, textural, and sensory properties were investigated during 28 days of storage at 4°C. The degradation kinetics of phenolic compounds were modeled using zero-order, first-order, and Weibull models, and the synergistic effect was evaluated by calculating the synergy index (SI). The encapsulation efficiency for GTE (84.3%) was significantly higher than that for MOE (76.8%). The microcapsules had particle sizes of 15-25 μm, moisture content <5%, and water activity <0.3. The Weibull model provided the best fit (mean R²=0.985). The half-life of phenolic compounds in encapsulated samples (20.4 days for GTE and 16.5 days for MOE) was significantly higher than in free samples (8.3 and 7.2 days), indicating a 2- to 2.5-fold increase in stability. The SI in the encapsulated form (1.088) indicated a strong synergistic effect, while the free form showed only an additive effect (SI≈1). The combined encapsulated treatment obtained the highest sensory acceptance score (18.85 out of 20), which was close to the control (18.50) and significantly higher than the free sample (15.30). Therefore, spray drying microencapsulation is an effective method for improving stability, creating synergistic effects, masking undesirable flavors, and enhancing the sensory acceptance of drinkable yogurt fortified with these extracts.
Keywords
Subjects
