Volatile components of the essential oils from Kabosu, Daidai, and Yuko, Japanese sour citrus fruits

Authors

  • S. M. Njoroge,

    1. Department of Bioresources Science, Faculty of Agriculture, Kochi University, B-200 Monobe, Nankoku City, Kochi, 783, Japan
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  • H. Ukeda,

    1. Department of Bioresources Science, Faculty of Agriculture, Kochi University, B-200 Monobe, Nankoku City, Kochi, 783, Japan
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  • H. Kusunose,

    1. Department of Bioresources Science, Faculty of Agriculture, Kochi University, B-200 Monobe, Nankoku City, Kochi, 783, Japan
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  • M. Sawamura

    Corresponding author
    1. Department of Bioresources Science, Faculty of Agriculture, Kochi University, B-200 Monobe, Nankoku City, Kochi, 783, Japan
    • Department of Bioresources Science, Faculty of Agriculture, Kochi University, B-200 Monobe, Nankoku City, Kochi, 783, Japan
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Abstract

The volatile components of kabosu (Citrus sphaerocarpa Tanaka), daidai (Citrus aurantium L. var. Cyathifera Y. Tanaka), and yuko (Citrus yuko Hort. ex Tanaka) peel oils were analysed by capillary GC and GC-MS, following extraction by cold-pressing. Sixty-six components were identified in kabosu oil, and sixty-two in each of those of daidai and yuko. The volatiles of yuko oil are reported for the first time in this study, and only fourteen of those in daidai oil had been previously identified. In kabosu oil, five sesquiterpenes, one monoterpene, and one alcohol, were newly identified. Monoterpene hydrocarbons accounted for about 98.0% in each oil. Limonene (94.7%) was the only major monoterpene in daidai oil, while myrcene in kabosu oil (18.5%), and γ-terpinene in yuko oil (21.3%) were the second most abundant. Sesquiterpene hydrocarbons constituted 1.5% of the yuko, 1.0% of the kabosu, and 0.2% of the daidai volatiles, and the most significant were respectively, β-elemene, β-farnesene, and germacrene-D. Among the oxygenated components, aldehydes were the most abundant in kabosu oil (0.6%), esters in daidai oil (1.4%), and alcohols in the yuko oil (0.9%). The flavour volatiles are assessed in relation to other Citrus oils.

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