Phenolic compounds in olive leaves have an excellent antioxidant activity and good antimicrobial properties. These bioactive molecules have beneficial properties for health, arousing great scientific and commercial interest. This study reports lyophilized olive leaf extracts (OLE) encapsulated by spray-drying using maltodextrins, maltodextrins–pectin and maltodextrins–gum Arabic as encapsulating agents. Lyophilized OLE were collected from two varieties cultivated in a harsh pedo-climatic conditions of the arid region of Tunisia. The effects of the genetic factor and the different encapsulating agents on the physicochemical properties of microcapsules and their behavior during storage, as well as their antimicrobial activities, were studied. Microcapsules successfully passed heat treatment and storage conditions and their antimicrobial activities were preserved. The encapsulating agent combination improved the encapsulation efficiency and the product yield in Zarrazi variety compared to Dhokar one. In addition, Dhokar variety microparticles showed the best heat stability at 4 and 25 °C after 90 days of storage and the higher inhibition percent against bacteria. The results of the present study evidenced that the best conditions for OLE encapsulation were obtained when the maltodextrins–pectin and maltodextrins–gum Arabic were combined to form a hybrid coating material.

Artemisia herba-alba Asso. is a medicinal plant rich in phenolic compounds with strong antioxidant and antimicrobial activities. However, these bioactive molecules are highly sensitive to environmental conditions, limiting their stability and potential applications. This study investigated, for the first time, the encapsulation of ethanolic extracts from the aerial parts of A. herba-alba by spray-drying, using maltodextrin (MD) and sodium caseinate (SC) as wall materials. The extract was obtained by ultrasound-assisted extraction, and both free and encapsulated forms were analyzed for phytochemical composition, antioxidant capacity, and antibacterial activity. Spray-dried microcapsules (SDE) were further characterized for encapsulation yield, efficiency, moisture, water activity, hygroscopicity, particle size, and structural integrity (SEM, ATR-FTIR, TGA/DTG). The process resulted in a high encapsulation yield (69.40%) and efficiency (96.39%), producing microcapsules with a small average size (10.05 ± 0.08 µm), low moisture (4.34%), low water activity (0.415), and moderate hygroscopicity (12.67%). Although the encapsulated extract showed lower total phenolic content, antioxidant capacity, and antibacterial activity compared to the free extract, SEM observations confirmed the formation of spherical, crack-free microcapsules, ATR-FTIR analysis revealed non-covalent interactions between wall materials and phenolics, and TGA/DTG demonstrated improved thermal stability. These results highlight spray-drying microencapsulation as an efficient approach to stabilize A. herba-alba phenolic compounds, offering promising applications as natural preservatives in the food industry.

Comprehending the variability in the chemical composition of olive oil from the same olive variety, based on its geographical origin, is essential. This study investigated the chemical composition of Chétoui olive oils from thirteen mills located in Northern Tunisia's Béja region. The chemical...