Changes in the Volatile Composition of Yuzu (Citrus junos Tanaka) Cold-Pressed Oil during Storage

Abstract

The changes of 34 components constituting a relative 97.6% of the total volatiles of yuzu (Citrus junos Sieb. ex Tanaka) cold-pressed peel oil and the possible artifacts during storage at -21, 5, and 20 °C were investigated after 1, 3, 6, 9, and 12 months. Major qualitative changes were found after 12 months at 20 °C. Total monoterpene hydrocarbons underwent a large decrease (from 93.3 to 37.7%), with major loses of limonene, γ-terpinene, myrcene, and R-pinene, while notable increases occurred in p-cymene as well as the monoterpene alcohols (from 2.1 to 13.2%). Bicyclogermacrene, the main sesquiterpene hydrocarbon of the fresh oil (1.0%), was virtually depleted. Sesquiterpene alcohols were formed as dominant artifacts (36.1%) and constituted the second most abundant volatile group of the oil after the monoterpene hydrocarbons. (-)-Spathulenol (decahydro-1,1,7-trimethyl-4-methylene-1H-cyclopropylazulen-7-ol) was the main artifact among the 14 identified. The alcohol constituted the second major component of the oil after limonene from the ninth month and accounted for more than 75% of the sesquiterpenic alcohols at 20 °C. The spathulenol was found for the first time to be an artifact in yuzu oil. The compound could be a useful index for monitoring the quality and freshness of yuzu flavor during storage.

Compositional Changes in Yuzu (Citrus junos) Steam-Distilled Oil and Effects of Antioxidants on Oil Quality during Storage

“…The behavior of compounds during storage was similar to that observed in the previous experiment in which yuzu CPO was stored at 20℃ for one year. However, the change in composition of SDO during storage took place more rapidly than in the case of CPO (Njoroge, et al, 1996). One reason for this may be the difference in storage temperature between the two experiments.…”

“…2) Of the artifacts, (-)-spathulenol (decahydro-1,1,7-trimethyl-4-methylene-1H-cyclopropylazulen-7-ol) was the main constituent (0.60 ± 0.05%). (-)-Spathulenol has been found to be an artifact in yuzu oil (Njoroge, et al, 1996). Yuzu fresh CPO contained this alcohol only in trace (LanPhi, et al, 2009).…”

“…Yuzu flavor is known to deteriorate rapidly during storage. The volatile compounds change significantly when yuzu oil is stored at room temperature, even for a period as short as one month (Njoroge et al, 1996). Changes in the chemical composition of steam-distilled yuzu oil have not been studied, although the compositional changes of yuzu CPO have been reported (Njoroge, et al, 1996).…”

“…The volatile compounds change significantly when yuzu oil is stored at room temperature, even for a period as short as one month (Njoroge et al, 1996). Changes in the chemical composition of steam-distilled yuzu oil have not been studied, although the compositional changes of yuzu CPO have been reported (Njoroge, et al, 1996). This paper examines the volatile composition of steam-distilled yuzu essential oil during long-term storage and the effect of some natural antioxidants on the quality of yuzu essential oil.…”

Design and Performance of a Compact Li+ Ion Attachment Mass Spectrometry System with an Atmospheric Sampling Device

“…The aroma compounds of many plants, including Yuzu, are well documented. The Yuzu aroma is mainly determined by a complex mixture of monoterpenes, monoterpene alcohols, and sesquiterpenes [16][17][18][19][20]. We report here our preliminary investigations on the emissions of various aroma compounds from Yuzu.…”