Extraction of Aroma and Functional Ingredients from Hydrous Immature Citrus Peel Using Supercritical Carbon Dioxide

Abstract

In this paper, the authors summarized the findings of extracting essential oils and polyphenols from wet immature citrus peels using the supercritical carbon dioxide (SCO₂) extraction and the Soxhlet one. Monoterpenes were the main components in the Soxhlet extraction (solvent: ethanol), while the selectivity of monoterpenes drastically decreased and that of oxygenated compounds greatly increased in SCO₂ extraction. Additionally, the total polyphenol content in the SCO₂ extraction reached about 80% of that obtained by the Soxhlet extraction, indicating that polar organic compounds, which are normally hard to extract, can be efficiently extracted in the presence of water content in peels.