Effects of different drying methods on the yield and the composition of essential oil from herb Mentha longifolia (L.) Hudso

Abstract

This paper discusses the impact of different methods of drying on the content and chemical composition of the essential oil from the herb Mentha longifolia (L.) Hudson. Drying of plant material was carried out naturally in the shade of draughty place, in the laboratory oven at the temperature 45°C and absorptive low temperature condensation drying oven at 35°C (low temperature drying). Isolation of essential oil from dried samples in three different ways was conducted by hydrodistillation, whilst chemical analysis was carried out by GC/FID and GC/MS methods. The highest yield of the essential oil was obtained from the herb which was dried at low temperature (1.1%) and the lowest from that dried in the laboratory oven (0.6%). The biggest content of the dominant component of essential oils, piperitone, was recorded in the oil from low temperature dried herb (71.7%), while those isolated from naturally dried drug and in from the laboratory oven contained piperitone in lower concentrations (50.8% and 43.1%, respectively).

Keywords

• drying
• essential oil
• Mentha longifolia L.
• piperiton