Response surface methodology employing a five-level, four-variable central composite rotatable design was applied to study the effects of extraction time, extraction temperature, pH and water/solid ratio on the extraction yield of pomegranate seed oil using an aqueous extraction approach. In addition, quality indices, fatty acid composition and antioxidant activity of the obtained oil were studied and compared with those of typical hexane-, cold press- and hot press-extracted oil. Aqueous extraction resulted in the maximum oil recovery of 19.3% (w/w), obtained under the following critical values: water/solid ratio (2.2:1.0, mL/g), pH 5.0, extraction temperature = 63 °C and extraction time = 375 min. This yield is lower than that obtained via hexane extraction (26.8%, w/w) and higher than the yields from cold press (7.0%, w/w) and hot press (8.6%, w/w) extraction. A comparison of the characteristics of the oils based on extraction method revealed that the unsaturated fatty acid content was highest for the oil obtained by aqueous extraction. In addition, higher levels of iodine and peroxide and lower levels of acid, p-anisidine and unsaponifiable matter were observed. The oil obtained with aqueous extraction also exhibited higher antioxidant activity than oils obtained by hexane or hot press extraction.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.