Microencapsulation of Araucaria angustifolia bract extract: protection and bioaccessibility of phenolic compounds in chitosan-based systems
Native to South America, Araucaria angustifolia bracts (an underutilized by-product of seed processing) account for nearly 80% of the pinecone and are commonly discarded. The lyophilized aqueous extract obtained from these residues is rich in phenolic compounds (PC) and exhibits antioxidant and antigenotoxic activities. However, the instability and low oral bioavailability of PCs limit their functional applications. This study aimed to microencapsulate Araucaria angustifolia extract (AAE) by spray drying using binary polymeric systems to enhance its stability and bioaccessibility. AAE was encapsulated using chitosan (CHI) combined with maltodextrin (MD) or Arabic gum (AG). The resulting microparticles were characterized by particle size, moisture content, morphology, yield, and encapsulation efficiency (EE). The bioaccessibility of total PC was assessed through simulated gastrointestinal digestion. Cytotoxicity was evaluated in intestinal cells as an initial assessment of biological safety. AAE-loaded microparticles exhibited particle sizes ranging from 4.80 to 5.54 μm, moisture content between 4.63 and 7.00%, and process yields between 42.43 and 51.61%. Encapsulation efficiency for total PCs was close to 100%. Microencapsulation ensured over 90% bioaccessibility after in vitro digestion and preserved antioxidant activity compared with free AAE. No cytotoxic effects were observed in Caco-2 cells at the concentrations tested, indicating the absence of acute cellular toxicity. Spray-drying microencapsulation using CHI-based binary systems (MD–CHI and AG–CHI) effectively stabilized phenolic compounds and preserved their bioaccessibility (> 90%), demonstrating potential as sustainable carriers for functional food and therapeutic applications. Applying nanotechnology to waste valorization supports the Sustainable Development Goals (SDGs) by promoting sustainable agriculture and the value-added use of regional biodiversity.