Subcritical water extraction of flavoring and phenolic compounds from cinnamon bark (Cinnamomum zeylanicum)

Cinnamon bark (Cinnamomum zeylanicum) powder was treated with subcritical water at 150 and 200 degrees C in a semi-continuous system at a constant flow rate (3 mL/min) and pressure (6 MPa). Major flavoring compounds, i.e., cinnamaldehyde, cinnamic acid, cinnamyl alcohol and coumarin, were extracted at lower recoveries than the extraction using methanol, suggesting that degradation of these components might occur during the subcritical water treatment. Caffeic, ferulic, p-coumaric, protocatechuic and vanillic acids were identified from the subcritical water treatment. Extraction using subcritical water was more effective to obtain these acids than methanol (50% v/v) in both number of components and recovery, especially at 200 degrees C. Subcritical water treatment at 200 degrees C also resulted in a higher total phenolic content and DPPH radical scavenging activity than the methanol extraction. The DPPH radical scavenging activity and total phenolic content linearly correlated but the results suggested that the extraction at 200 degrees C might result in other products that possessed a free radical scavenging activity other than the phenolic compounds.