Seasonal Change of Volatile Compounds of Citrus sudachi during Maturation.

Seasonal change of volatile components in Citrus sudachi was monitored by headspace gas-chromatographic analyses. The limonene content increased sharply from 50.87% (unripe sudachi) to 87.23% (over-ripe sudachi) in accordance with maturation of the fruit, while α-thujene, sabinene, α-phellandrene, β-ocimene and γ-terpinene decreased. Linalool decreased particularly sharply during maturation from 5.20% to 0.55%. Other oxygenated compounds such as cis- and trans-limonen-1,2-oxide, citronellal, decanal, terpinen-4-ol and carvone were not detected in unripe sudachi but appeared in the volatiles during the ripening progress. These oxygenated terpenes had larger log Uo values (>1). Furthermore, as limonene, α-pinene, decanal, citronellal, linalool are the characteristic odor chemicals in sudachi, these increase and decrease of odor active terpenes during maturation are determined to contribute to the change of the characteristic aroma and the generation of sudachi-like aroma.