Freeze-drying (FD) was preceded by freezing cut kale leaves for
80 min at 40 C on trays in the lyophilizing cabinet of a Feutron
type 3101-01 air freezer with forced air circulation. Drying was
carried out in a CHRIST Gamma 1-16 LCS lyophilizing cabinet. The
process of freeze-drying was begun at an initial temperature
of 25 C. The process was terminated in accordance with the results
of earlier tests, which showed that a water content of below
5% was obtained after 30 h of drying, when the temperature of the
dried material and that of the trays in the lyophilizing chamber
reached 30 C. After drying, the material from the trays was mixed
and packed in air-tight containers (glass twist-off jars 2.0 L in
volume