Evaluation of methyl chavicol concentration by different evaporation processes using central composite experimental design

Abstract

This work describes methyl chavicol enrichment from basil essential oil by wiped film evaporation (WFE) and compares its performance with published data obtained by short path evaporation (SPE). The main difference between these processes is that the WFE presents an external condenser, while the SPE uses an internal one. The evaporation processes comparison was performed based on methyl chavicol concentration level and amount of produced material. Through central composite experimental design, the influences of evaporator temperature, condenser temperature, and feed flow rate on distilled percentage and methyl chavicol concentration at the residue stream were studied. Response surface methodology based on five level-three variable was used to describe the individual and interactive effects between factors on the process. From experimental data, models were built up to describe distilled percentage and methyl concentration at the residue stream in function of operating conditions. Results showed that, in the studied range, similar methyl chavicol concentration (near to 89%) was reached using both WFE and SPE processes, however, at different operating conditions. While higher concentrations of methyl chavicol were obtained at 28°C and 0.133kPa using WFE, similar methyl chavicol content was obtained at 70°C and 1.33kPa using SPE. However, WFE presented higher separation efficiency because, although similar concentration levels were reached using both equipments, the amount of produced material in the residue stream was 10% higher in WFE.