To understand the loss of total nitrogen observed during fermentation,
the empirical hypothesis that purines (theobromine
and caffeine) migrate from cotyledon to shell during fermentation
was checked. Nitrogen content of whole cocoa samples still carrying
their shell was measured during fermentation in parallel to
cocoa shells alone, and compared to previous results.
Whatever the origin and phenotype of the samples, nitrogen
content increased within the shell, reaching 34.7 lg g1 of dried
shell, while it decreased in the cotyledon. Since the sum of nitrogen
from both compartments (cotyledon and shell) was similar to total
nitrogen value from the whole bean, and since nitrogen balance of
the whole bean during fermentation remained constant (Fig. 1b),
one may suppose that there was a migration of nitrogenous compounds
from cotyledon to the shell.