Optimization of Essential Oil Extraction from Dried Clove Leaves (Syzgium aromaticum) using Solvent-Free Microwave Extraction by Face-Centered Central Composite Design

Abstract

Clove (Syzygium aromaticum) leaves are agricultural waste of clove plants which can still be valorised by extracting their essential oil. The the aim of this research is to perform the extraction process of clove essential oil using Solvent free microwave extraction by studying the effects of extraction parameters, such as microwave power, feed to distiller ratio and extraction time and finding optimal conditions with the response surface methodology using FCCD design. The operating parameters of this experiments are microwave power (300 -600 W), feed to distiller ratio (0.06 - 0.14 g/mL), and extraction time (20 - 60 minutes). The existence of analysis of variance values (ANOVA) which indicates an important factor that determines the results of the study. From the analysis results obtained 4 parameters that have a significant effect (p-value <0.05), these parameters are microwave power (A), F/D ratio (B), Extraction Time (C) and the effect of extraction time squared (C2). The results showed that the optimum conditions were at microwave power 542,04 W, F/D ratio 0.07 g / mL, extraction time 44.5 minutes. From this optimum condition, the maximum prediction result is 4.45%. It can be neglected that these results indicate the suitability of the model used in the extraction of dry clove leaf essential oil (R2 = 0.8906). Chemical analysis was also carried out using GC-MS. The results showed that the largest component was Eugenol 95.68%. While the physical properties, specific gravity 1.62 and solubility 1: 2. The results of the value analysis are in accordance with the range of quality standards SNI 06-2387-2006.