Oxidative Stability of Papaya Seed Oil From Hainan/Eksotika Obtained by Subcritical and Supercritical Carbon Dioxide Extraction

Papaya seed is a good source of edible oil with considerable antioxidant activity. Here, papaya seed oil (PSO) of Hainan/Eksotika variety was obtained by subcritical butane extraction (SBE) and supercritical carbon dioxide extraction (SCDE), and its yields, physicochemical properties, oxidative and thermal stability, and chemical and microscopic structures were compared. The results showed that SBE-PSO had a higher yield (25.88 +/- 0.29% vs. 19.47 +/- 0.92%), but a lower melting point compared to SCDE-PSO. Molecular structures indicated that there was no oxidative degradation during SBE and SCDE. Both SBE and SCDE caused significant structural changes of seed tissues. In addition, aldehyde composition analysis using high performance liquid chromatography (HPLC) showed that SBE-PSO had fewer octanal, nonanal, 2-decenal, and 2-undecenal contents than SCDE-PSO. All these results proved that SBE-PSO exhibited superiority on the oxidative stability compared to SCDE-PSO. It indicated that SBE was a superior method to obtain antioxidant edible oil with good stability.