Supercritical CO2 extraction of passion fruit (Passiflora edulis sp.) seed oil assisted by ultrasound

• The use of ultrasound in the supercritical CO2 extraction of passion fruit seed oil lead to increases in the process rate and yield.
• Tocopherol and tocotrienols were identified in the extracted oil by HPLC.
• DPPH scavenging activity was verified on the oils, demonstrating correlation with tocopherol and tocotrienols.
• Fatty acids composition did not change on different experimental conditions.
• Images obtained by FESEM showed changes caused by SFE with and without ultrasound in the sample’s microstructure.

This work evaluated the effect of ultrasound, temperature and pressure on the supercritical CO2 extraction of passion fruit seed oil. The raw material was a by-product of the pulp processing industry (seeds mixed with pulp). Fatty acids, tocopherol and tocotrienol composition and DPPH radical scavenging activity were evaluated. The obtained oil was rich in polyunsaturated fatty acids (about 67%), tocopherol and tocotrienol (between 60 and 90 mg/100 g oil), presented high DPPH radical scavenging activity (between 1.8 and 2.6 mg TE/g oil), which showed correlation with the tocopherol and tocotrienol total content (r = + 0,872). The application of the ultrasound power of 160 W favored the oil extraction, since the SFE global yield improvement achieved 29% (at 40 °C and 16 MPa). The mathematical model of Sovová (1994) was able to describe the extraction kinetics. There were increases of the constant extraction rate time and of the fluid phase mass transfer coefficient, and reduction of the solute ratio inside the cells due to the ultrasound application. The images obtained by field emission scanning electron microscopy showed mechanical damage and smaller particle size when ultrasound was applied.

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