Premium
Kinetics of isothermal and microwave extraction of essential oil constituents of peppermint leaves into several solvent systems
Author(s) -
Spiro Michael,
Soon Chen Sau
Publication year - 1995
Publication title -
flavour and fragrance journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.393
H-Index - 70
eISSN - 1099-1026
pISSN - 0882-5734
DOI - 10.1002/ffj.2730100407
Subject(s) - chemistry , isothermal process , solvent extraction , solvent , chromatography , kinetics , essential oil , extraction (chemistry) , microwave , organic chemistry , thermodynamics , physics , quantum mechanics
The rates and extents of extraction have been measured for three major constituents of peppermint oil, namely 1,8‐cineole, menthone and menthol, using the leaves of the black mint ( Mentha × piperita L.). The solvents used were hexane, ethanol and mixtures of composition 90 mol% ethanol + 10mol% hexane and 90mol% hexane + 10mol% ethanol. The extractions were carried out isothermally at 25, 35 and 45°C as well as in an electrically and mechanically modified domestic microwave oven where the temperature increase varied from c. 10 to 30°C. The rates of both isothermal and microwave extractions were sensitive to the solvent employed and decreased in the order 90mol% hexane > 90mol% ethanol > hexane > ethanol. The rates of microwave extraction were also affected by the microwave power output and the size of the sample load. The activation energies for the extractions were in the range 30‐90kJ mol −1 , again dependent on the solvent used. Scanning electron microscopy on the spent leaves provided evidence of a link between the kinetics of extraction and structural changes on the glands.