Response surface methodology: An optimal design applied for maximum ultrasound-assisted extraction efficiency of phenolic acids from Coriandrum sativum L.

Phenolic composition of coriander fruit

Abstract

In this study, a combined three-factors-three-level Box-Behnken design with a response surface methodology was used to optimize the ultrasound-assisted extraction of bound phenolic acids from coriander fruits. Temperature (X1, 20-60 °C), sonication time (X2, 15-45 min) and NaOH concentration (X3, 2-4 M) were studied as independent variables in order to obtain the optimal extraction conditions. For this purpose, a two-step analytical procedure was applied: first, alkaline hydrolysis and extraction under the influence of ultrasound was performed followed by a clean-up step using solid-phase extraction method. After derivatisation, the extracted phenolic acids were analysed using GC-MS. The interrelationship between the dependent and operational variables were well fitted (R2 >0.90) to the quadratic term models. The results obtained in this study confirmed that studied factors had a significant influence on phenolic acids extraction recovery. In favour of maximum extraction yields, the following experimental conditions are suggested: a sonication time of 17.4 min at 35.3°C and with a NaOH concentration of 2.02 M. These results can be utilized for further isolation of active phenolic compounds from other parts of coriander plant as well as for phenolic acids study over various plant materials from the Apiaceae family.