Volatile composition of sweet basil essential oil (Ocimum basilicum L.) as affected by drying method

The influence of drying method on aroma compounds of sweet basil (Ocimum basilicum L.) was evaluated. The drying methods tested were convective (CD) and vacuum-microwave (VMD), as well as a combination of convective pre-drying and VM finish-drying (CPD-VMFD). Sweet basil's drying kinetics for CD was described by a two term exponential model, while VMD kinetics consisted of two periods: linear until a critical point and exponential beyond that point. Volatile compounds of basil samples were extracted by hydrodistillation and analyzed by GC/FID and GC/MS. Forty compounds were tentatively identified, with methyleugenol, eugenol, eucalyptol, and linalool being the major components. The total quantity of volatiles of fresh sweet basil, 32.1 g kg− 1, decreased considerably during both CD and VMD, 14.4 g kg− 1. The CPD-VMFD (40 °C and 360 W) was the best option for drying sweet basil, the time required was relatively short (≈ 250 min), and aroma quality was good according to instrumental data (total concentration of volatiles 16.7 g kg− 1) and sensory data (high intensities of fresh and floral notes).

► Convective pre-drying and vacuum-microwave finish drying was the best drying method. ► CPD-VMFD provided dried basil of the highest quality. ► Methyleugenol, eugenol and eucalyptol predominated in sweet basil essential oil.