The total solids were determined gravimetrically by drying the
samples in a vacuum oven at 60 C to constant weight. The density
was determined by the volume displacement technique using pycnometers,
with toluene as the solvent. The thickness of each slice
was calculated from the mass of discs of known diameter and
the values obtained for density. The reducing and total sugar contents
of the slices were determined by the colorimetric method of
Somogyi–Nelson (Nelson, 1944; Somogyi, 1945). Oxyreduction
titration (AOAC, 1970) was used to determine the initial sugar content
of the fresh sample. The sodium concentration was determined
using a flame photometer Digimed DM61/Brazil-SP (AOAC,
1984).