The Change of Drying Time and Quality Parameters of Lemon Balm (Melissa officinalis L.) with Different Temperature Profiles of Drying Air

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Ertuğrul M.

Journal of New Results in Engineering and Natural Science, vol.9, no.2019, pp.1-10, 2019 (Peer-Reviewed Journal)


Lemon balm ( Melissa officinalis L.), one of commercially important medicinal and aromatic plants, must be dried immediately after harvest because of its high initial moisture content (72.99% to 80.11%, wb). Its quality parameters such as its color and essential oil conditions are very sensitive to drying conditions. The most important factor of drying conditions is the drying air temperature profile. Five different drying air temperature profiles were used to maintain the quality parameters of lemon balm samples while reducing the drying time as much as possible. Drying trials with the constant low temperature (35 °C) and the increasing temperature profile gave the most closest color values of dried samples to the ones of fresh samples. The maximum color changes occurred with the constant high temperature (60 °C) and the triangle temperature profile. The drying trials with the constant low temperature gave the lowest essential oil loss (24.28% loss) while the drying trials with the constant high temperature gave the highest essential oil loss (63.95% loss). The increasing temperature profile in which the drying air temperature increased from 35 °C to 60 °C in 8 hours became the most convenient drying air temperature profile for drying lemon balm when the results obtained in this study were evaluated altogether.