Determination of odor active aroma compounds in freshly cut leek (Allium ampeloprasum Var. bulga) and in long-term stored frozen unblanched and blanched leek slices by gas chromatography olfactometry analysis

The odor active compounds in freshly cut leek slices and in blanched and unblanched leek slices stored for 12 months were investigated by a detection frequency method. Fifteen judges were evaluating the three samples randomized. The most important aroma compounds in the freshly cut leek slices were dipropyl disulfide, methyl propenyl disulfide, pentanal, decanal, and propyl propenyl disulfide in order of priority. When stored frozen and unblanched for 12 months, the aroma composition changed and the most important compounds became pentanal, decanal, 2,5-dimethyl furan, unknown compound I, and dipropyl disulfide. Blanching before freezing prevented to some degree these changes but also reduced the perceived intensity of the aroma compounds. The most important aroma compounds in the blanched sample were dipropyl disulfide, unknown compound I, pentanal, 2,5-dimethyl furan, and propyl propenyl disulfide.