The present study also showed that the composition
of the isoflavones could vary from one step to another
during processing. The malonyl conjugates were especially
unstable when exposed to heat. The levels of
isoflavone aglycones, daidzein and genistein, increased
by 12- and 23-fold, respectively, due to the soaking,
heating, and grinding processes. Levels of malonyl
daidzin and malonylgenistin decreased, due to the
cleavage of malonyl ester groups to form daidzin and
genistin upon heating and grinding. It is well documented
that the profile of isoflavones changes due to
temperature during processing. It is also reported
that malonyl glucosides are easily decarboxylated
to their corresponding acetyl derivatives, as we
observed.