Ultrasound-Assisted Aqueous Enzymatic Extraction of Oil from Pomegranate Seeds

Pomegranate seed oil presents nutraceutical properties. Industrial processes for extraction of edible oils from seeds generally involve a solvent extraction step. Safety considerations on the use of organic solvents prompted attempts to develop aqueous extraction. However, aqueous extraction processes are usually characterized by low oil yields. The objective of this work was to overcome these low yields by using enzymes. The pomegranate seeds were treated with two enzymes—cellulase and Peclyve V. The extraction temperature, the time, the enzyme concentration, and the water/seeds ratio were varied between 35 and 55 °C, 2 and 8 h, 2 and 4 % w/w, and 2/1 and 6/1 mL/g, respectively. The optimum yield accomplished (15.33 g oil/100 g dry seeds at 2 h or 81 % oil recovery) was comparable to the yields obtained by other extraction methods, such as normal stirring, cold pressing, superheated fluid extraction, indirect ultrasound-assisted extraction and supercritical extraction, (4.29–25.11 g oil/100 g seeds) at similar or longer extraction times (10 min–72 h). In addition, this work studies the enhancement of aqueous enzymatic extraction of pomegranate seed oil by ultrasound probe. It was found that only 10 min in water are needed to recover oil with a yield of 18.15 g oil/100 g dry seeds, a value similar to or higher than those of the conventional procedures. Thus, the use of ultrasounds increased the yield of enzymatic extraction by 18.4 % and reduced the extraction time by 91.7 %.