Relationship between the chemical and sensory properties of exotic salad crops—coloured lettuce (lactuca sativa) and chicory (cichorium intybus)

Samples of red-coloured lettuce and chicory were assessed for bitterness by sensory analysis and compared with conventional green-coloured varieties. The amounts of the sesquiterpene lactones lactucin, 8-deoxylactucin and lactucopicrin and their glycosides were determined using enzyme hydrolysis and high performance liquid chromatography. The level of each of these compounds was compared with the bitterness score found for each sample, and the resulting correlation data suggested that the increasing level of one of these compounds, lactucin glycoside, was closely related to the increase in bitterness.