Simultaneous Extraction of Water and Essential Oils from Citrus Leaves and Peels Using Liquefied Dimethyl Ether

Most of the residues after extracting juice from the citrus fruit are discarded, although they contain valuable substances such as flavonoids and essential oils. While most of the citrus flavonoids are present in the fruit peel, various valuable substances are also contained in the leaves. Moreover, the leaves and peels of citrus plants contain a large amount of moisture; hence, dewatering is essential for extracting valuable substances. Herein, we used liquefied dimethyl ether (DME) as the extractant for dewatering and extraction of valuable substances. With this process, >70% of the water from the wet samples was removed and valuable substances were isolated from the wet samples. The properties of the original and dewatered samples and the extract were evaluated using high-performance liquid chromatography. While the essential oils could be extracted, it was not possible to extract flavonoids by the liquefied DME method.