S-alk(en)yl-L-cysteine sulfoxides and relative pungency measurements of photosynthetic and nonphotosynthetic tissues of Allium porrum.

Three standard assays for pyruvate gave equivalent measurements of relative pungency for two leek cultivars ( 'Tadorna' and 'Ramona'). Background pyruvate levels varied depending on the assay used, ranging from 0.4 (lactate dehydrogenase) to 1.