Optimisation of microwave-assisted extraction of Gac oil at different hydraulic pressure, microwave and steaming conditions

The study aimed to optimise Gac (Momordica cochinchinensis Spreng) oil extraction conditions, including microwave time, steaming time and hydraulic pressure, for maximising extraction efficiency (EE), and β-carotene and lycopene contents, using response surface methodology. Results indicated that the data were adequately fitted into three second-order polynomial models for EE, β-carotene and lycopene with R² values of 0.93, 0.85 and 0.86, respectively. It was predicted that the optimum extraction conditions within the experimental ranges would be the microwaving time of 62 min, steaming time of 22 min and hydraulic pressure of 175 kg cm^-2. Under such parameters, the maximum EE of 86%, β-carotene content of 186 mg per 100 mL oil and lycopene content of 518 mg per 100 mL oil were achieved as predicted.