TY - JOUR
T1 - Conversion and hydrothermal decomposition of major components of mint essential oil by small-scale subcritical water treatment
AU - Chiou, Tai Ying
AU - Nomura, Shiori
AU - Konishi, Masaaki
AU - Liao, Chien Sen
AU - Shimotori, Yasutaka
AU - Murata, Miki
AU - Ohtsu, Naofumi
AU - Kohari, Yoshihito
AU - Lee, Wei Ju
AU - Tsai, Tsung Yu
AU - Nagata, Yuichi
AU - Saitoh, Tohru
N1 - Publisher Copyright:
© 2020 by the authors.
PY - 2020/4
Y1 - 2020/4
N2 - Thermal stabilities of four major components (l-menthol, l-menthone, piperitone, and l-menthyl acetate) of Japanese mint essential oil were evaluated via subcritical water treatment. To improve experimental throughput for measuring compound stabilities, a small-scale subcritical water treatment method using ampoule bottles was developed and employed. A mixture of the four major components was treated in subcritical water at 180–240 ◦C for 5–60 min, and then analyzed by gas chromatography. The results indicated that the order of thermal resistance, from strongest to weakest, was: l-menthyl acetate, l-menthol, piperitone, and l-menthone. In individual treatments of mint flavor components, subsequent conversions of l-menthyl acetate to l-menthol, l-menthol to l-menthone, l-menthone to piperitone, and piperitone to thymol were observed in individual treatments at 240 ◦C for 60 min. As the mass balance between piperitone and thymol was low, the hydrothermal decomposition of the components was considered to have occurred intensely during, or after the conversion. These results explained the degradation of mint essential oil components under subcritical water conditions and provided the basis for optimizing the extraction conditions of mint essential oils using subcritical water.
AB - Thermal stabilities of four major components (l-menthol, l-menthone, piperitone, and l-menthyl acetate) of Japanese mint essential oil were evaluated via subcritical water treatment. To improve experimental throughput for measuring compound stabilities, a small-scale subcritical water treatment method using ampoule bottles was developed and employed. A mixture of the four major components was treated in subcritical water at 180–240 ◦C for 5–60 min, and then analyzed by gas chromatography. The results indicated that the order of thermal resistance, from strongest to weakest, was: l-menthyl acetate, l-menthol, piperitone, and l-menthone. In individual treatments of mint flavor components, subsequent conversions of l-menthyl acetate to l-menthol, l-menthol to l-menthone, l-menthone to piperitone, and piperitone to thymol were observed in individual treatments at 240 ◦C for 60 min. As the mass balance between piperitone and thymol was low, the hydrothermal decomposition of the components was considered to have occurred intensely during, or after the conversion. These results explained the degradation of mint essential oil components under subcritical water conditions and provided the basis for optimizing the extraction conditions of mint essential oils using subcritical water.
KW - Conversion
KW - Hydrothermal decomposition
KW - Mint essential oil
KW - Subcritical water treatment
KW - Thymol
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U2 - 10.3390/molecules25081953
DO - 10.3390/molecules25081953
M3 - Article
C2 - 32331471
AN - SCOPUS:85083800539
SN - 1420-3049
VL - 25
JO - Molecules
JF - Molecules
IS - 8
M1 - 1953
ER -