Molecular encapsulation of citral or d-limonene flavor by spray drying

摘要

Lemongrass oil and d-limonene are typical flavor oils used in the food and cosmetic industries. Lemongrassoil displays some therapeutic properties such as analgesic, antimicrobial, fungicidal, deodorant, etc. Citral,the main active component of lemongrass oil, consists of a mixture of two isomeric acyclic monoterpenealdehydes: geranial and neral. Molecular encapsulation of these flavors was investigated by spray drying.Cyclodextrin (CD) and modified starch were used as encapsulants that made up the wall material of thespray-dried powders. CD can control flavor release rate and protect the encapsulated flavor fromvolatilization by the formation of inclusion complex. CD content in the wall material affected themorphology, flavor retention, and flavor stability of the spray-dried powders. d-Limonene and citral inlemongrass oil encapsulated within the matrix of CD were the most stable. However, the retention of dlimoneneand citral was the highest in their respective wall materials of pure modified starch and highlybranched cluster dextrin (HBCD). Microscopy of the spray-dried powders revealed that hollow structure ofthe powders was influenced by the content of cyclodextrin in the wall material. The inclusion complexationability of β-CD could possibly remedy the inefficiency of Capsul? in protecting the encapsulated citralagainst oxidation over time due to its “leaky” structure.