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ABSTRACT
This study aimed at evaluating the potential of gum arabic in combination with maltodextrin for the microencapsulation of cinnamon essential oil by spray drying to maximize its hygroscopic, thermal and chemical stability. The corresponding isotherm exhibited type II behavior (sigmoidal curve), and the best fit was obtained for the GAB model (E = 4.81%). Differential scanning calorimetry (DSC) analysis showed that the increased moisture content caused a significant reduction of the glass transition temperature (Tg) of the microparticles. Microparticles stored at intermediate humidity exhibited thermal stability and a lower mass loss, while storing at low temperatures led to higher antioxidant capacity and cinnamaldehyde retention.
Keywords: Sorption Isotherms; Glass transition; Cinnamon essential oil; Antioxidant activity; Gordon-Taylor equation
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PRACTICAL APPLICATIONS
Knowledge about the stability of encapsulated foods is of great importance for the food industry in which the behavior and physicochemical and sensorial alterations of these microparticles subjected to different conditions of storage and process can be predicted.
INTRODUCTION
Cinnamon essential oil (Cinnamomum zeylanicum) is one of the most used products in the pharmaceutical, food, and cosmetic industries due to its chemical and sensory characteristics. The oil is predominantly composed of cinnamaldehyde, which exhibits excellent antioxidant and antimicrobial activity (Cardoso-Ugarte et al., 2016).
Spray drying is the most common dehydration process used for sensitive foods as flavors, essential oils, herbal extracts, enzymes, lipids, oleoresins, fruits, and colorants, pharmaceuticals (Cortés-Rojas & Oliveira 2012, Goula & Adamopoulos 2012), and other substances because of the rapid solvent evaporation from the droplets (Mahdavi et al., 2014). This process involves packaging the core material in a polymer matrix in three steps: atomization, dehydration, and powder collection for increased protection and stability (Fang & Bhandari 2012, Fernandes et al., 2013).
Gum arabic and maltodextrin are the materials most commonly used to ensure good protection of the encapsulated compounds (Akhavan Mahdavi et al. 2016b, Ferrari et al., 2013, Mahdavee Khazaei et al., 2014, Oliveira et al., 2013, Pitalua et al. 2010, Rajabi et al., 2015, RochaParra et al., 2016). Carbohydrate biopolymers exhibit plasticizer characteristics, promoting the formation of spherical and smooth-surface microcapsules and increasing the bonding strength between the wall and core material. This strong interaction inhibits undesirable reactions caused by different storage conditions (Akhavan...