Microencapsulation of Phenolic Extracts from Verbascum sinaiticum Leaf Using Maltodextrin and Gum Arabic: Physicochemical Properties, Encapsulation Efficiency, and Storage Stability

Verbascum sinaiticum (V. sinaiticum), locally known as “Qetetina” in Ethiopia, is a rich source of phenolic compounds, but its stability and sensory limitations restrict its application. This study evaluated the physicochemical, functional, morphological, structural, storage stability, and in vitro digestibility characteristics of V. sinaiticum extract encapsulated with 100% Gum Arabic (GA), 100% maltodextrin (MD), and a mixed coating material (MD:GA = 8:2 ratio) using freeze-drying. MD-based microcapsules demonstrated superior functional properties, including high water solubility (98.48%), low moisture content (1.36%), low hygroscopicity (14.61%), and high encapsulation efficiency (81.31%). During 32 days of storage, MD microcapsules retained 71.84% of total phenolic content and showed minimal release under gastric and thermal conditions, while GA encapsulates were less stable. Structural analysis using XRD, FTIR, and SEM confirmed successful encapsulation, with compact morphology, consistent phenolic preservation, and structural integrity. Furthermore, encapsulation masked the undesirable sensory attributes of the extract, enhancing its potential use in nutraceuticals. Overall, freeze-drying with MD provided the most effective encapsulation system, significantly improving the stability and storage potential of V. sinaiticum extract.