Volatile Retention and Enteric Release of d-Limonene by Encapsulation in Complex Coacervated Powders Formed by Spray Drying

Abstract

A novel, industrially scalable spray-drying process to form complex coacervated (CoCo) powders was applied to encapsulate limonene. This study investigated how to control the barrier properties of the matrix formed by the novel process to retain limonene in the dry powder and to control its release in aqueous media. The matrix was formed by gelatin, alginate, and succinic acid to control the pH facilitating electrostatic interactions between the polymers. The CoCo powders formulated with 4% gelatin, 0.5% alginate, either 0.5 or 0.75% succinic acid demonstrated enteric release of limonene and minimal limonene release in water. The enteric release of CoCo powders correlated with the extent of complex coacervation, indicating dissolution as the primary release mechanism. The CoCo matrix also provided robust protection of the volatile compound during spray drying, where ∼78% limonene was retained and subsequent 4 months storage at room temperature where only 2−8% limonene loss was incurred.