keep their pores closed during the day to
conserve water, then open them at night to
take in carbon dioxide, which they then store
in the form of malic acid. During the day, they
use the energy from sunlight to convert the
malic acid to glucose. Pads harvested in the
early morning therefore contain as much as 10
times more malic acid than pads harvested in
the afternoon. The acid levels in the pads
slowly drop after harvest, so the difference is
less apparent after a few days.
Cardoons Cardoons are the leaf stalks of
Cynara cardunculus, the Mediterranean plant
from which the artichoke (C. scolymus)
apparently descends; the stalks are often
covered for several weeks before harvest to
protect them from sunlight, or blanch them.
Cardoons have a flavor quite similar to the
artichoke’s, and are abundantly endowed with
astringent, bitter phenolic compounds that
quickly form brown complexes when the