Optimization of Ohmic Heated Extraction Using Response Surface Methodology and Quality Attributes of Dabai (Canarium odontophyllum) Pulp Oil

Abstract

The process for extracting oil from dabai pulp using ohmic heated extraction is optimized by response surface methodology. The effects of ohmic heated extraction parameters on both the quantity and quality of oil yield were investigated. A central composite design was employed, focusing on factors such as voltage (40–60 V), temperature (70–90 ℃), and extraction time (15–30 min), with the production of dabai oil being the goal response. Optimized ohmic heated extraction for dabai pulp oil using response surface methodology achieved optimal conditions at 40 V, 70 °C, and 15 min with a predicted oil yield of 22.07% and an experimental yield of 23.12 ± 0.46%. The ohmic heated extraction process outperformed Soxhlet extraction in energy efficiency by requiring only 0.060 ± 0.004 kWh compared to 0.122 ± 0.056 kWh by Soxhlet extraction for a higher oil yield. The refractive index of the ohmic heated and Soxhlet extracted oil samples ranged from 0.623 to 0.625. The specific gravity ranged from 1.010 to 1.020. Both methods yielded oils with a yellowish color, indicating similar oil quality. The oil extracted via ohmic heating, containing pentadecane, (E)-2-heptanal, and terpinen-4-ol, was identified through gas chromatography-mass spectrometry. Scanning electron microscopy analysis highlighted significant structural changes in dabai pulp under ohmic heated extraction supporting the method’s efficiency. Overall, ohmic heated extraction presents a viable and sustainable alternative to traditional extraction methods for dabai pulp oil, offering improved efficiency and quality for industrial applications.