Methyl epijasmonate in the essential oil of tea.

Abstract

Methyl epijasmonate has a 400 times stronger aroma than methyl jasmonate, which is known to be one of the key compounds in the aroma of tea, and the former is easily isomerized on heating. Reinvestigation of the separation and identification of tea aroma compoundsindicated that steam distillation should be performed under reduced pressure, and that the gas chromatographic conditions should be controlled at below 170°C using an open tubular column coated with a nonpolar liquid phase to avoid the isomerization or decomposition of methyl epijasmonate. Under the conditions, ten types of teas were analyzed, and methyl epijasmonate wasshownto contribute to the aroma of tea, particularly, to that of Chinese semi-fermented teas.

Response of tea quality parameters to time of year and nitrogen fertiliser

“…However, the FI should only be used qualitatively since the olfactory perception limits of individual VFC are different. Some compounds could occur at low levels but affect the perception significantly and vice versa (Owuor et a1 1987(Owuor et a1 , 1988Kobayashi et al 1988). The summary of the variations in the VFC with time of year and nitrogen application are presented in Fig 1. The extent of variations is presented in Table 2 for all the chemical quality parameters measured.…”

Methyl Dihydrojasmonate and Its Stereoisomers: Sensory Properties and Enantioselective Analysis

“…In the literature, injection temperature is solely emphasized to avoid epimerization during GC analysis of methyl jasmonate. [27] We analyzed MDHJ at different injection temperatures (180-2508C) and did not observe any dependence of the temperature on the epimer ratio. In our experience, the injection port temperature alone is not the crucial point to avoid epimerization.…”

Coffee, cocoa, and tea

“…Year 1896 1916 1920 1934 1935 1937 1938 1940 1957 1958 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1979 1980 1981 1983 1984 Total References (152) (190)(191)(192) (193)(194)(195)(196)(197)(198) (199)(200)(201) (135,202) 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 Year Figure 3. Discovery of tea flavor constituents.…”

“…The presence in different varieties of tea of methyl epijasmonate (F-15b), which has a 400 times stronger aroma than F-15a, has been recently studied (196). The odor thresholds of methyl jasmonate isomers have been measured by the "combined hedonic response measurement" (CHARM), using high-resolution gas chromatography, effluent sniffing, and computerized data collection (478).…”