Abstract

This study aimed to maximize the oil yield from Gac seed kernels using supercritical carbon dioxide (SC-CO₂) extraction. Gac seed kernel powder (4 g) with particle diameters <500 μm was extracted for 32 min. Response surface methodology with central composite design was used to optimize the SC-CO₂ extraction parameters: temperature (60-80°C), pressure (5,000-7,000 psi (34,474-48,263 kPa)) and SC-CO₂ flow rate (1-2.5 mL/min). The oil yield, accurately represented by a second order equation (R² = 0.99, p<0.0001), was predicted to be most substantially and significantly influenced by temperature (p<0.0001), followed by pressure (p<0.02) but not by the CO₂ flow rate (p = 0.20). The optimum conditions were predicted to be: temperature of 73°C, pressure of 5,900psi (40,679kPa) and CO₂ flow rate of 1.5 mL/min. The optimum oil yield was predicted to be 34.1±0.8% (g oil/100 g Gac seed kernel powder) and experimentally validated at 33.9±0.5%. The oil was likely high in saturated fat, being solid at room temperature and having a low iodine value, with 33.2±1.1% being unsaponifiable matter.

Keywords:

Extraction, Momordica cochinchinensis, oil, response surface methodology, supercritical carbon dioxide,

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