Reduction of limonene chlorohydrins in commercial citrus oils

Commercial cold-pressed citrus oils containing terpene chlorohydrins may have quality and safety implications for end-users of these oils. Concentrations of (1S, 2S, 4R)-2-chloro-8-p-menthen-1-ol (1), (1R, 2R, 4R)-2-chloro-8-p-menthen-1-ol (2), and (1R, 2R, 4R)-2,9-dichloro-8-p-menthen-1-ol (3) in some citrus essential oils ranged from less than 1 ppm to 30 ppm measured by gas chromatography with a halogen detector. Reduction reactions of these compounds were accomplished by continuous mixing (reaction) of the oil with dilute solutions of KOH. Greater than 95% reduction of 1 and 3 were accomplished after reaction for 15 h with 0.5 N KOH or after 24 h with 0.25 N KOH in oils with either 25 or 30 ppm (1). Similar treatment of an oil containing 5 ppm (1) resulted in reduction to below the threshold limit of quantification (0.4 ppm). Sensory analyses of tasting solutions did not detect any flavor difference between untreated or KOH-treated oils.