Optimization of ohmic parameters in enzyme assisted aqueous extraction for better physico-chemical properties of the black cumin seed oil

This study was carried out to optimize the ohmic heating parameters for enhancing physico-chemical properties of oil from enzymatic hydrolyzed black cumin seed. The effect of electric field strength (EFS) including 550, 650,750,850 and 950 V/m, the end point temperatures (EPT) 50, 60, 70, 80 and 90 degrees C, holding time (HT) 0, 5, 10,15 and 20 min and pH levels 2, 3, 4, 5 and 6 were optimized for the extraction process. The response in terms of oil yield, refractive index, specific gravity, color, free fatty acids, saponification, and peroxide values of the extracted oil was studied. Statistical analysis and optimization of process parameters were performed using the response surface methodology. The results revealed that 56.54-64.18% of oil yield was obtained in enzymatic aqueous extraction and in combination with ohmic heating, was increased from 64.18% to 85.71%. From the numerical optimization it is observed that, EFS of 718.22 (V/m), EPT of 66.08 (degrees C), HT of 14.07 (min) and pH of 3.7 facilitates the oil yield, specific gravity, color, free fatty acid, saponification, and peroxide values were 79.12%, 0.798, 46.68, 0.672%, 181.42 mg KOH/g and 1.128 meq O-2/kg, respectively. It is confirmed that there is not statistically significant (P < 0.05) difference was observed between the predicted and actual values. Thus, it could be concluded that the optimum conditions of ohmic heating parameters could be enhanced by oil yield and maintaining the natural of physico-chemical properties of enzymatically hydrolyzed black cumin seed oil.