Comparison of Peel Oil Components of Yuzu (Citrus junos Tanaka) Extracted by Supercritical Carbon Dioxide and Those of Traditional Ones

Abstract

Peel oils of yuzu (Citrus junos Tanaka) were extracted by supercritical carbon d ioxide (SCCO₂) from peel residues of juice extraction or raw peels. The characteristics of oils were compared with those of cold-pressed or solvent-extracted oils. A pilot plant for SCCO₂ was operated at 15°C under 100kg/cm² in an extractor (4l) and at 30°C under 40kg/cm² in a separator (2l). 1) The yield of peel oils from crushed yuzu peel residues by SCCO₂extraction was 1.2%, while the yield from raw peels without crush was as much as 3.9%. 2) The physical constant values of refractive index and specific gravity were simil ar in each oils, but specific rotation was different between SCCO₂-extracted oils and other oils. 3) Mono and sesquiterpenes in addition to higher-boiling point components containing linaloo β-farnesene, bicycloelemene and thymol were extracted highly by SCCO₂ as compared with cold-pressed or solvent-extraction.