Optimization of sonication-assisted hydrodistillation for essential oil extraction from Citrus macroptera peel: A comparative study of RSM and ANN
Md. Idrish Ali, Parvej Hasan Jon, Jahid Hasan Shourove, Oliur Rahman, G. M. Rabiul Islam
Abstract
• Citrus macroptera peel valorized via sonication-assisted hydrodistillation (SAHD). • ANN outperformed RSM in predicting essential oil yield, TPC, and DPPH activity. • Max essential oil yield was 1.87 ± 0.11 % under ANN optimized extraction condition. • Limonene (56.36 %) and isoeugenol (7.35 %) detected via GC MS analysis. • SAHD showed reduced energy use and CO 2 emission than hydrodistillation. This study optimized the extraction of essential oil (EO) from Satkora ( Citrus macroptera ) peel using sonication-assisted hydrodistillation (SAHD), applying response surface methodology (RSM) and artificial neural networks (ANN). A Box-Behnken design assessed the effects of solvent-solid ratio (SSR), sonication time (ST), and hydrodistillation time (HT) on EO yield, total phenolic content (TPC), and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. Optimization was performed using RSM with a desirability function and ANN integrated with a genetic algorithm. ANN-GA identified optimal extraction conditions at an SSR of 7.84:1, ST of 29.17 min, and HT of 159.36 min, yielding 1.87 ± 0.11 % EO, 106.22 ± 0.27 mg GAE/g TPC, and 68.85 ± 0.15 % DPPH scavenging activity. The ANN model outperformed RSM in predicting EO yield, exhibiting a lower root mean square error (RMSE = 0.0067), mean absolute error (MAE = 0.0055), standard error percentage (SEP = 0.3711), and a higher coefficient of determination (R 2 = 0.9923), compared to RSM. Gas chromatography mass spectrometry revealed limonene (56.36 %) as the major compound, followed by isoeugenol (7.35 %) and eugenol acetate (5.31 %). The EO exhibited favorable physicochemical properties, including a low acid value (3.24 ± 0.1 mg KOH/g) and a refractive index of 1.25 ± 0.0021. Additionally, energy consumption and CO 2 emissions were evaluated, confirming the environmental advantage of SAHD over conventional hydrodistillation. These findings highlight the potential of SPEO for use in pharmaceutical, food, cosmetic, and essential oil industries.