some 23 were identified and considered to be the
compounds accounting for most of the aroma of the
Of these organics there were twelve phenols, five
aliphatic acids, two C4 alcohols and ketones and four
mono-and di-unsaturated aldehydes. Reconstitution
experiments based on the above compounds, at their
measured concentrations in the cured beans, were
sensorially similar to a Mexican vanilla extract [ 17].
The biochemical and/or chemical origin of most
of these aroma compounds has not been established,
though it is clear that virtually all are released or
generated during curing. Vanillin and most of the
other identified phenols were present in the green
beans as their b-D-glucosides are liberated by
hydrolysis primarily during the fermentation stage of
curing [ 18].
Further transformation of some of the liber-
ated phenols may occur to realize additional
functionalized phenols. Non-phenolics may arise
from polyunsaturated fatty acids by b-oxidation
or lipoxygenase-type reactions and/or fatty acid
synthesis. These latter reactions realize short chain,
mainly unsaturated aldehydes, that contribute to
the overall final flavor impact of cured vanilla beans
[ 19, 20]. Amino acids by Strecker type-degradation
or enzymatic transformation can realize Strecker
aldehydes and the C4 hydroxyl and keto compounds
acetoin and diacetyl, respectively [ 21]. Both diacetyl
and acetoin are Strecker catalysts.
In the vanilla bean, the primary reaction involves
release of the free phenols by hydrolysis of their b-D-glucosides. Secondary reactions involving further
transformation of the liberated mono-phenols may
occur under mild drying conditions employed. Of
the other key compounds in cured vanilla beans,
unsaturated fatty acids are likely to be involved in
their formation. In cocoa bean roasting, the major
important aroma compounds appear as a result of
thermal processing. These include 4-hydroxy- 2,5-di-
methyl- 3(2H)-furanone and the Strecker aldehydes
3-methylbutanal and phenylacetaldehyde. The major
difference between the two raw materials in terms of
flavor generation may be a reflection of more extensive hydrolysis of selected proteins and subsequent
thermal treatment during cocoa bean processing.
Similarities in Vanilla and Cocoa Bean
There are, however, some parallels between
curing of vanilla and cocoa bean processing in terms
of the common stages of fermentation and drying.
Traditionally, both of these appear to be important.
It is significant, however, that the Mars Incorporated
Vanilla flavor is dominated by phenols and their transformation products mostly
derived from enzymatic hydrolysis of the phenyl-b-D-glucosides. Cocoa bean
flavor is dominated by Strecker aldehydes and pyrazines and other products
generated during the roasting process of the beans.