Optimization of Aqueous Enzymatic Extraction of Castor (Ricinus communis) Seeds Oil Using Response Surface Methodology

Aqueous enzymatic extraction (AEE) was applied to obtaining the free oil from castor (Ricinus communis) seeds in this study. Individual enzymes and enzymatic combinations were screened, and the reaction conditions of AEE were modified using response surface methodology. And the effects of solvent extraction (SE) and AEE on the oil's physicochemical properties were compared. The enzyme of nutrase was found to be the best one in extracting free oil compare to other enzymes (cellulase, hemicellase, pectinase, and amylase), and the highest oil recovering rate of 77.53% was achieved under optimal experimental conditions of hydrolysis temperature (47 degrees C), enzyme concentration (3%), ratios of material to water was (1:3.7) (w/v) and hydrolysis time (4.5 hours). Compared with SE oil, AEE oil was more acidic and had a higher hydroxyl value but did not affect the fatty acids composition. SEM results illustrated nutrase mainly breakdown cells and oil bodies' membranes structure of castor seeds resulting in high free oil releasing. The results demonstrated that AEE is a promising environmental friendly technology for oil extraction of castor seeds in the oil industry.