Agronomy journal, Vol. 69 No. 1, 2007.
Original scientific paper
THE INFLUENCE OF MEDIUM TEMPERATURE IN THE DRYING PROCESS OF PEPERMINT (Mentha Piperita) LEAVES ON THE ESSENTIAL OIL CONTENT
S. Pliestić
Nadica Dobričević
D. Filipović
Abstract
The thin-layer drying of peppermint leaves was determined in a (cabinet) dryer. The leaves were dried at 350C, 450C and 600C until establishment of the weights. The essential oil was extracted by distillation in a Clevenger apparatus and analyzed by gas chromatography-mass spectrometry (GC-MS). Higher drying temperature sharply decreased the essential oil content (% v/w) from 1.23% (350C) to 0.78% (450C) and 0.18% (60°C). Moisture content of fresh peppermint leaves was from 83.17 to 84.93 %w.b., and moisture content of dried mint leaves from 10.16 to 10.72 %w.b.. The specific gravity of the fresh mint leaves (Mohsenin) was 786.28 kg/m3 and of the dry peppermint leaves: 984.32 kg/m3. The bulk density of the fresh leaves was 29.11 kg/m3 and of the dry ones 17.93 kg/m3.
The increase in air temperature significantly reduced the drying time of the peppermint leaves, but also affected the composition, increasing the menthol and neomenthol content to 60°C.
Keywords
peppermint leaves; drying; essential oil
Hrčak ID:
18199
URI
Publication date:
23.2.2007.
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