Gac oil and carotenes production using supercritical CO2: Sensitivity analysis and process optimization through a RSM–COM hybrid approach

• Analysis of the commercial extraction of oil and carotenes from gac aril using supercritical CO2.
• SFE optimization performed by combining response surface methodology (RSM) and cost of manufacturing (COM) approach.
• Optimum (P,T,t) conditions for oil extraction are 400 bar, 60 °C, 1 h; for carotenes extraction are 400 bar, 50 °C, 1 h.
• Best production costs of gac oil and carotenes are very promising according to current trade quotations.

Gac (Momordica cochinchinensis Spreng) is a traditional fruit from Southeast Asia whose aril oil has been investigated owing to the remarkable abundance of oil and carotenes (e.g. β-carotene and lycopene). In this context, supercritical fluid extraction (SFE) using CO2 is an option for the exploitation of this raw material. In this work a hybrid approach combining cost of manufacturing (COM) and response surface methodology (RSM) concepts was applied to lab results of SFE of gac oil with the objective of finding the operating conditions that ensure the best technical and economic performance of the process. Upon specifying a SFE commercial process comprising a fruit drying line followed by two extractors of 0.4 m3 in parallel, the impact of extraction pressure (200–400 bar), temperature (40–60 °C) and time (0.5–2.0 h) on manufacturing costs and productivity was assessed. The best COM for oil extraction was found for 400 bar, 60 °C, and 1.0 h, amounting 8€ kgoil−1. Regarding specifically extraction of carotenes, the best COM was attained for 400 bar, 50 °C, and 1.0 h, amounting 755€ kgcarotenes−1. Both production costs are encouraging in relation to current market quotations of gac oil and purified (>90%) carotenes. Finally, a sensitivity analysis to flow rate was accomplished. In the whole, the outcomes of this study support the exploitation of gac oil and naturally occurring carotenes from gac aril through supercritical CO2 extraction.

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