Changes produced in the aroma compounds and structural integrity of basil (Ocimum basilicum L) during drying

The influence of drying on the aroma compounds, from a chemical and sensory standpoint, and on the structural integrity of basil (Ocimum basilicum L) was evaluated. The drying methods tested were oven drying at 45 °C, air drying at room temperature and freeze-drying. The volatile compounds of fresh and dried basil were extracted and concentrated by simultaneous distillation/extraction and analysed by gas chromatography/mass spectrometry. In all, 27 volatile components were identified, linalool being the major component, followed by eugenol. The total quantity of volatiles of fresh basil decreased considerably during oven drying and freeze-drying, whereas air drying of basil at room temperature brought about only small losses of volatile components. The cell damage produced on basil leaves during drying was evaluated by scanning electron microscopy. From a sensory standpoint, fresh basil was described as having a fresh, herbaceous and floral odour, while the dried samples had a mentholated, spicy, hay-like and earthy odour.