Extraction and Comparison of Limonene Contents of Wastes in Citrus Species for Reuse

Identification and extraction of limonene in fruits of the genus Citrus L. which has several medicinal, cosmetic, and industrial properties, is crucial for reusing fruit wastes after they have been processed into fruit juice. The aims of the current study are therefore (i) to compare limonene contents in different fractions such as peels, pulps and juices of citrus species including orange (C. cinensis L.), lemon [C. limon (L.) Osbeck], grapefruit [C. paradisi (L.) Macfad.] and tangerine (C. tangerina Tanaka)), (ii) to extract limonene from the most abundant fraction of selected citrus species and (iii) to optimize the extraction parameters of supercritical fluid carbon dioxide (SFC) extraction system. The limonene contents were determined using high performance liquid chromatography (HPLC) and extraction conditions of SFC were optimized by Response Surface Methodology (RSM). The highest limonene content was determined in the peel fraction of the lemon. The limonene was found to be