Essential oil constituents of three varieties of Kenyan sweet oranges (<i>Citrus sinensis</i>)

Abstract

Abstract The volatile components of peel essential oils of Salustiana ( Citrus sinensis Osbeck forma Salustiana ), Valencia ( C. sinensis Osbeck forma Valencia ) and Washington navel ( C. sinensis Osbeck forma Washington navel ) sweet oranges grown in Kenya were isolated by cold‐pressing and determined by GC and GC‐MS. A total of 56 components were identified in Salustiana, 73 in Valencia and 72 in Washington navel peel oils. The identified components amounted to 98.7, 97.8 and 97.4% of the total volatiles of each oil, respectively. Monoterpene hydrocarbons largely dominated in the volatile fraction of the Salustiana (96.9%), Valencia (94.5%) and Washington navel (92.7%) oils. In each oil, limonene, α ‐pinene, sabinene and α ‐terpinene were the major compounds. Sesquiterpene hydrocarbons amounted to 0.1% of the total volatiles of Valencia and Washington navel oils, where ( E,E )‐ α ‐farnesene was the main compound. The total oxygenated compounds amounted to 1.7, 3.4 and 4.5% of the Salustiana, Valencia and Washington navel volatiles. Linalool, decanal, ( Z )‐carvone, ( Z )‐carveol, ( E )‐carveol, nootkatone and sabina ketone were the main components. The three sweet orange varieties could be differentiated by the unique presence of α ‐phellandrene and γ ‐terpinene in Salustiana, β ‐phellandrene, ( Z )‐nerolidol, aromadendrene in Valencia and p ‐cymene, β ‐sinensal and dodecanoic acid in Washington navel oils. Copyright © 2004 John Wiley &amp; Sons, Ltd.