2.2. Isolation of Volatile Components from Broccoli

Broccoli sample was blended and 50 g of pulp was weighed and transferred to a 500 mL Erlenmeyer flask, to which 200 mL of dichloromethane was added, and the content in the flask was stirred with a magnetic stirrer for 2 h. After this time the solution was filtered and subjected to volatiles extraction in a SAFE apparatus (Glassbläserei Bahr, Manching, Germany) [12]. During the procedure the temperature of the sample was kept at 40 °C and vacuum was provided using a dual stage rotary vane pump (RV-5, Edwards, UK). The sample was poured into addition funnel and the liquid nitrogen was added into the cooling trap. After the sample addition, the extraction lasted for 30 min. Then, the extract was dried over anhydrous sodium sulphate and concentrated to about 1.5 mL in Kuderna-Danish concentrator (Sigma-Aldrich, Poznań, Poland) and immersed in a 40 °C water bath. The extraction was performed according to procedure described by Majcher and Jeleń [10].

For SDE extraction, a Clavenger type apparatus was used. A sample of 50 g of blended broccoli was placed in a 500 mL flask and mixed with 70 mL of distillated water. The round-bottom flask was attached to the bottom of SDE apparatus and placed in a heating mantle. A pear-shaped 50 mL flask containing 20 mL dichloromethane as extraction solvent was connected to the second arm of the instrument. The distillation/extraction was performed for 2 h and after that, the extract was dried over anhydrous sodium sulphate and concentrated to about 1.5 mL in a Kuderna-Danish concentrator immersed in 40 °C water bath. The extraction was performed according to procedure described by Majcher and Jeleń [10].

The SPME fiber (DVB/CAR/PDMS) was preconditioned in the injection port in 270 °C per 1 h before analysis. 4 g of blended broccoli sample was placed in a 20 mL vial. The extraction was performed at 50 °C, the sample was preheated for 5 min and then the fiber was exposed in the vial for 10 min. The extraction was performed according to Wieczorek and Jeleń methodology [13]. All analyses were run in triplicate.