|Authors: ||D. Havkin-Frenkel, J.C. French, N.M. Graft, F.E. Pak, C. Frenkel, D.M. Joel|
The fruit of the climbing orchid Vanilla planifolia (vanilla bean) is used for the commercial production of the prized vanilla flavor, consisting of vanillin and other numerous flavor compounds, with the use of a curing process.
However, present curing methods yield only a fraction of the vanilla flavor from flavor precursors in green beans.
Studies on the botany of vanilla beans revealed that flavor precursors are found in the bean interior, where they are secreted onto the placental region around the seeds, whereas hydrolytic or other degradative enzymes, which catalyze the release of the flavor precursors to flavor compounds, are localized mostly in the outer fruit wall region.
This insight suggests that the objective of killing, the first curing stage carried out by hot water scalding, freezing or by other methods, is to disorganize the bean tissue, such that contact is created between substrates and their respective enzymes.
Sweating, a subsequent step in curing, entailing high temperatures (usually around 45° to 65° C) and high humidity, provides conditions for enzyme-catalyzed production of flavor compounds and also for non-enzymatic reactions.
The objective of the final curing steps, including drying and conditioning, is to dry the cured beans to preserve the formed flavor compounds.
Further understanding on the botany and curing of the vanilla bean may render a full recovery of flavor from the flavor precursors in vanilla beans and, subsequently, significant economic gains.
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