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In the Lab
by Rick Brownell
The correlation between vanillin content and vanilla quality
When prices of vanilla
beans soared from 2000 to 2004, a simultaneous decline in vanillin content
was also a somewhat overlooked cause for concern. Vanillin content is an
important indicator of bean quality, which has improved in recent years,
but has still not returned to pre-crisis levels.
Vanillin is the most predominant chemical compound in
vanilla beans. Typically, the vanillin content before the crisis was 1.70
to 1.85 percent in extraction-grade vanilla beans, as measured by HPLC
(AOAC 990.25). An alternate method of analysis, UV Spectrophotometer (AOAC
966.12), may also be used, but is less accurate because it measures other
phenolic compounds in addition to vanillin.
During the vanilla crisis, the vanillin content of
vanilla beans averaged only 1.20 to 1.30 percent by HPLC. The decline
resulted primarily from large quantities of immature beans, which were
either sold at discounted prices or blended with mature beans to lower the
overall average cost of the lot. The abundance of immature beans resulted
from early picking by growers, who feared they would be stolen if left on
the vines until full maturity. Since vanillin precursors form primarily
during the last few months on the vine, early picked beans are far lower in
vanillin content.
Another cause of early picked beans was the cyclones
of 2000 and 2004. They blew many beans off the vines, several months before
they were ready to be harvested. Too valuable to be left to rot, these
beans were gathered and processed, subsequently finding their way into the
market as well.
Immature beans have other quality problems besides low
vanillin. The flavor profile is inferior because other important flavor
components are also under developed. This tends to accentuate the woody,
earthy characteristics of extracts made from these beans. Immature beans
are also more susceptible to mold, since vanillin is a natural mold
inhibitor. While mold can be eradicated in beans themselves, the associated
musty flavor remains. Finally, immature beans are often cured and stored by
growers unfamiliar with the proper techniques for doing so, resulting in
detrimental off-notes.
Today, there are still ample quantities of early
picked beans available. But with it being a buyers market, most lots of
first-quality extraction grade beans have a vanillin content of 1.40 to
1.60 percent by HPLC. Still not back to pre-crisis levels, but a
significant improvement from just a few years ago.
Looking ahead, it is important that food and beverage
companies recognize the relationship between vanillin content and quality
in vanilla beans and extracts. They should request that extract suppliers
include vanillin content by HPLC in product specifications and provide
certificates of analysis (COA’s) with each lot. Lower-priced extracts
are more often than not made from lower-quality beans.
Vanillin content provides an easy and effective guide
for evaluating and ensuring the quality and consistency of vanilla beans
and extracts.
Rick Brownell is vice president of vanilla products
for Brooklyn, N.Y.-based Virginia Dare.
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