EFFECT OF CONDITIONS OF EXTRACTION BY SUPER-HIGH PRESSURE ON THE YIELD OF OIL OF TREE PRIMROSE
Optical properties of ethanolic extract of the oil of tree primrose seeds (Oenothera biennis L.) are studied. To extract the oil, a new method was applied, namely, extraction by super-high pressure (ESHP). The spectral composition of the optical density of the primrose oil was registered. It was found that pressure effect substantially increases the fraction of fatly acids from 6.6% under atmospheric pressure up to 35.5% under 100 MPa. The mechanism of ESHP was studied. The existence of two modes of diffusion in different pressure ranges is demonstrated. The modes are characterized by native membranes and partially or totally damaged ones. The effective diffusion coefficients are calculated in these areas; D<sub>0h</sub> = 11.743·10<sup>-13</sup> m<sup>2</sup>/s and D<sub>0u</sub> = 8.339·10<sup>-13</sup> m<sup>2</sup>/s, respectively. The use of fitting curves provided optimum pressure values associated with the maximum yield of oil. In our case, the optimum pressure is P = 87.95 MPa.