Optimization of different drying methods and its impact on antioxidant potential of Ocimum basilicum L.

In the present study, the effect of different drying methods (sun drying, shade drying, oven drying at 35 °C, 45 °C, 55 °C and hot air blower drying) was assessed to optimize the essential oil (EO) quality of Ocimum basilicum L. The fresh and dried samples were hydrodistilled using a Clevenger apparatus to extract the EO. The EO composition was determined by GC and GC–MS techniques. The antioxidant activity was measured using 2, 2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity; FRAP activity and Fe²⁺- ferrozine test system for iron chelating activity methods. The content of iron, copper, zinc and manganese were analyzed by Atomic Absorption Spectrophotometer (AAS). Sun dried O. basilicum showed the highest EO yield (0.8%, v/w). Linalool (10.67–32.91%) and methyl chavicol (16.24–58.00%) were present as the major components in all the EOs being the highest for blower dried and shade dried samples respectively. EO obtained from the shade dried material was showing the highest antioxidant potential followed by blower dried plant sample. Dried material exhibited higher micronutrient content as compared to the fresh one. The shade drying method can be a good option for obtaining the best quality essential oil from O. basilicum in terms of the major component and antioxidant potential.