Effect of Different Drying Methods and Packing Material on Quality of Thyme (Thymus vulgaris L.) During Storage

Document Type : Original Article


 THIS INVESTIGATION was carried out during successive seasons ……of (2010/2011) and (2011/2012) at El-Kassassin Hort. Res. Station, Ismailia Governorate, Hort. Res. Institute, A. R. C., Egypt, to evaluate the effect of drying methods; oven at 45°C, shade at 20 ± 2°C, greenhouse at 35 ± 5°C and sun at 30 ± 3°C and packing materials; carton boxes, glass jars, cotton bags and polyethylene bags during the different storage periods of 2, 4, 6, 8, 10 and 12 months on volatile oil, moisture content and herb pigments content, in the thyme (Thymus vulgaris L ) plant herb.
The highest values of volatile oil percentage was obtained from the oven drying method, while the lowest values was obtained from sun drying method. On the other side, the highest values of dry matter resulted from the shade drying, while the lowest resulted from the sun drying. Oven drying recorded the highest moisture content per 100 g fresh herb, while the lowest values recorded by shade drying in both seasons.
The G.L.C. of the volatile oil revealed that 12 compounds were identified as following Tricyclene, α-Pinene, Camphene, α–Terpinene, Limonene, 1,8-cineol, p- cymene, Camphor, Linalool, Borneol, Thymol and Carvacrol. The major componemts were Limonene and Thymol.
The oven drying combined with both glass jars or carton boxes recorded the highest values of chlorophyll (a), chlorophyll (b) and carotene content in herb, while the sun drying method combined with polyethylene bags recorded the lowest values in this respect during both seasons.
The storage period from 2 to 12 months decrease in the chlorophyll (a), chlorophyll (b) and carotene content of thyme herb in the two seasons.