Conversion and Hydrothermal Decomposition of Major Components of Mint Essential Oil by Small-Scale Subcritical Water Treatment

Autor: Tai-Ying Chiou, Shiori Nomura, Masaaki Konishi, Chien-Sen Liao, Yasutaka Shimotori, Miki Murata, Naofumi Ohtsu, Yoshihito Kohari, Wei-Ju Lee, Tsung-Yu Tsai, Yuichi Nagata, Tohru Saitoh
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Molecules, Vol 25, Iss 8, p 1953 (2020)
Druh dokumentu: article
ISSN: 1420-3049
DOI: 10.3390/molecules25081953
Popis: 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.
Databáze: Directory of Open Access Journals
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