Identification of aroma compounds in raw and cooked broccoli

Broccoli is characterized by its specific flavor, which is the reason it is not tolerated by some consumers. The role of aroma in flavor is crucial; however, the characteristics of aroma-active components in broccoli are still unclear. Solvent-assisted flavor evaporation (SAFE) with the aid of solid-phase microextraction (SPME) and fractionation using solid phase extraction (SPE), followed by different chromatography-mass spectrometry approaches (GC-MS, GC-MS/MS, GCxGC-ToFMS) were used to identify the compounds of interest. A total of 33 aroma-active compounds were detected with the use of gas chromatography-olfactometry (GC-O) in raw, and 9 in cooked broccoli florets; in majority sulfur compounds-thiols, sulfides, and isothiocyanates prevailed. Methanethiol and 1-pentanethiol were the key odorants characterized by the highest FD (1024) in raw broccoli, followed by dimethyl sulfide, 2,3-butanedione, dimethyl trisulfide, dimethyl tetrasulfide, 2-methyl methanethiosulphonate, 4-methylpentyl isothiocyanate, hexyl isothiocyanate (all with an FD of 256). In cooked broccoli, the number and especially the intensity of detected compounds were much lower. The highest FD values (FD=4) were noted for dimethyl trisulfide and 1,4-octadien-3-one. To our knowledge, this is the first detailed identification of odorants in raw and cooked broccoli.

Automated summary

The study employed various techniques to identify the odorants in raw and cooked broccoli, revealing that the aroma of broccoli is primarily derived from sulfur compounds, with a significant decrease in intensity after cooking.