Quality and active constituents of safflower seed oil: A comparison of cold pressing, hot pressing, Soxhlet extraction and subcritical fluid extraction

Safflower seed oil (SSO) is suitable for nutritional and pharmacological applications due to its high content of linoleic acid and polyphenols. The study aims to investigate the quality of SSO extracted using different extraction methods. In this study, solvent extraction (SE), cold pressing (CP), hot pressing (HP), and subcritical fluid extraction (SFE) by dimethyl ether (SDE), n-propane (SPE), and n-butane (SBE) were used to extract oil from SSO. The physicochemical indexes, bioactive compounds, and oxidative stability of SSO were analyzed and compared. In all samples, the main fatty acid found was linoleic acid, ranging from 76.1% to 79.49% of total fatty acids. SE dramatically improved phytosterol content (up to 311.8 mg/100 g) and yield (up to 23.1%) in SSO. The SFE oils had a higher oxidation induction time (4.28-4.38 h) and α-tocopherol content (580.1-643.7 mg/kg) than other oils (0.76-3.22 h and 451.5-511.7 mg/kg, respectively). In SSO samples, phenolics were particularly abundant in SDE oils. Trachelogenin was the most abundant in all samples. Compared to all the other oils, SFE oils had better oxidative stability, with almost the highest yield, and had higher linoleic acid content, phytosterols, and tocopherols. SFE is a promising processing technology in nutrient-rich SSO.