Pomegranate (Punica granatum L.) seeds are normally waste products from pomegranate fruit processing but they are a valuable source of certain pharmaceutical and nutraceutical compounds. This study was performed to determine and compare the physico-chemical properties of oils of pomegranate seed extracted by cold pressing from the variety Torshe Malas Iran (TMOI) and two commercial oils from Iran (COI) and Turkey (COT). Fatty acid analysis indicated that all the oil samples had a dominant fatty acid, punicic acid, with the other prominent fatty acids being linoleic and oleic acids. The thermal behavior of the three oils was determined using differential scanning calorimetry, which gave melting points of TMOI (−12.70°C), COI (1.87°C), and COT (2.25°C). TMOI was found to have the most favorable chemical quality attributes, including a low peroxide value (4.67 meq/kg), low free fatty acid content (0.65% as punicic acid), and high total phenolic content (10.44 mg GAE/g sample), followed by COT. Analysis of flavor compounds was conducted using fast gas chromatography-surface acoustic wave technology, which allowed detection of 13 distinct aromas among the three oils. Overall, the physico-chemical properties of the three oils were superior to those of pomegranate seed oils extracted using organic solvents reported previously.
Practical application: Medical applications of pomegranate seed oil are gaining increasing attention, particularly due to the health benefits of punicic acid. Pomegranate seed oil is also highly suited to specific industrial applications, such as tanning. Despite its importance, little research has been conducted on the physico-chemical properties of the oil extracted by cold press compared to conventional extraction methods and super critical CO2 extraction. This study shows that superior quality pomegranate seed oil can be extracted simply and without using organic solvents. Extraction of the highly nutritious cold-pressed oil from pomegranate seeds could enable the generation of substantial revenue for pomegranate processing factories without associated environmental impacts.