Physicochemical characteristics of Actinostemma lobatum Maxim. kernel oil by supercritical fluid extraction and conventional methods

Abstract

There are limited studies available regarding the characteristics of Actinostemma lobatum Maxim. kernels. In the present study, the kernels were analyzed for their nutritional composition, especially their oil characteristics. Expressed on the dry weight basis, the kernel oil accounted for 47 % of the kernel, whereas the content of protein represented 26 %. The major unsaturated fatty acids of the kernel oils were linoleic acid and oleic acid (43 %–44 % and 37 %–38 %, respectively). The kernel oils were found to be rich in squalene, tocopherols, and phytosterols (2327–2975, 676–759, and 504–676 mg/kg, respectively). More specifically, δ-tocopherol was the most abundant tocopherol and Δ5-avenasterol was the major sterol in the kernel oils. Furthermore, three different oil extraction methods (supercritical CO2 extraction, Soxhlet extraction, and cold pressing) were applied and the physicochemical properties of the extracted oils were compared. No significant differences (P > 0.05) were found in tocopherol and sterol contents for the three extraction methods. Higher oil yield and oil recovery were obtained by supercritical CO2 extraction. Overall, A. lobatum kernel is a promising valuable source of bioactive substances and essential fatty acids for future applications in food, pharmaceutical, and cosmetic industries.