Influence of Drying Processing on Essential Oil Yield and Composition of Wild Marigold (<i>Tagetes minuta</i> L.) in the Western Himalayas

Abstract

The effect of drying processing was investigated in wild marigold (Tagetes minuta L.) in the western Himalayas. Experiment on three drying methods (shade, sun, and oven) and seven post-harvest drying time (0, 12, 24, 36, 48, 60, and 72 h) were studied under a completely randomized design. The essential oil (EO) was obtained by hydrodistillation and was analyzed by GC and GC/MS. The moisture content of tagetes herbage was lower, while essential oil yield (g/kg dry matter) was significantly higher in sun drying for 72 h. The total area percentages of identified compounds of T. minuta essential oil were 90.5 to 94.5 % for drying method and 85.9-96.7 % for drying time. Drying methods and drying time had no significant impact on the number of EO components, as 9 chemical constituents were identified in every drying treatment. The major components were (Z)-ocimene, dihydrotagetone, (E) & (Z)-tagetone, and (E) & (Z)-tagetenone. The EO amount and the area percentage of its two main components (Z)-ocimene and dihydrotagetone were significantly influenced by the different drying methods and time. Higher proportions of (Z)-ocimene and lower proportion of dihydrotagetone in the EO of sun-dried tagetes herbage for 60 h were more pronounced. Further increase in drying time caused a greater loss in the percentage of (Z)-ocimene.

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