Sept. 13 was International Chocolate Day! What better time to enjoy one of our
most beloved treats. Chocolate is as versatile as it is tasty, and you may
already be aware of the health benefits of cocoa, and in particular, dark
chocolate. The health benefits of cocoa, and in particular dark chocolate, are
well documented. Dark chocolate is healthier than milk chocolate because it
contains more cocoa solids and therefore has more antioxidants (called
flavanols), which may promote cardiovascular health.
But did you know that U.S. Department of Agriculture Agricultural Research
Service researchers at the Food Science and Market Quality and Handling
Research Unit (FSMQHRU) in Raleigh, N.C., are developing a healthier milk
chocolate?
ARS food technologist Lisa Dean and her team at FSMQHRU are using peanut skins
to fortify milk chocolate, thereby increasing the chocolate's antioxidant
levels. Peanut skins contain phenolic compounds including procyanidins which
have been shown to reduce inflammation and act as natural antioxidants and
antimicrobials.
Unfortunately, peanut skins are very high in tannins, which give them a bitter
taste, so skins are usually removed in processing during blanching or dry
roasting. Because 50 percent or more of the peanuts grown in the United States
are made into peanut butter, all of those removed skins are a major source of
processing waste for the industry. Peanut skins can be used in animal feed, but
the levels have to be low to keep the animals from rejecting the feed. This
leaves the peanut industry with a large amount of peanut skin waste with little
to no commercial value.
Dean and her team discovered that some of the phenolic compounds contained in
the skins are the same catechins that are in tea, cranberries, and cocoa, and
provide health benefits such as antioxidant activity and anti-inflammatory
properties. But how do you capture the valuable phenolic compounds for
valued-added uses?
Since the ARS research unit is located in the Food, Bioprocessing and Nutrition
Sciences Department at North Carolina State University, they were able to have
a group of students in a Senior Design class develop a way to combine the
soluble extracts with maltodextrin, a starch-based polysaccharide, to make a
free-flowing powder that was easier to handle and would control the bitterness.
The resulting powder could then be used as a functional food ingredient,
albeit, with the caution that the allergenicity of peanuts carries over to
peanut skins. (Therefore, any product using the powder derived from the skins
would have to report peanut allergy information on the label.) ARS researchers
looked for possibilities to use the value-added ingredient in a way that
consumers would associate with peanuts. Well, what pairs better with peanuts
than chocolate?
"The phenolic compounds in cocoa are the reason for the health benefits
attributed to dark chocolate, but they are also why dark chocolate is bitter.
If you have ever tried one of the dark chocolate bars that are very high in
cocoa (over 80%) you may have found it tasted more like tobacco than chocolate.
Also, because dark chocolate contains less cocoa fat, it is brittle and does
not melt smoothly," said Dean These are a few of the reasons why people
often prefer milk chocolate over dark chocolate.
With this in mind, ARS researchers decided to investigate the possibility of
increasing the antioxidant levels in milk chocolate to those found in dark
chocolate.
Working with the ARS team, a graduate student prepared a series of milk
chocolate squares containing increasing levels of the peanut skin powder. These
chocolate squares were used in a threshold test during which a group of 100
consumers tasted the fortified squares along with some that did not contain any
of the peanut skin ingredient. What Dean's group discovered was that most
consumers could not tell if there was an additive in the chocolate until the
level of the peanut skins was well above the level that had antioxidant
activity equal to dark chocolate.
In a separate study, ARS researchers also used the peanut skin additive to make
flavored coatings--honey roasted, chocolate-covered, and chili lime--for
peanuts. Phenolic compounds were extracted from peanuts skins and then combined
with 10.5% maltodextrin. Various concentrations of the extract were added to
the flavored coatings on roasted peanuts. The scientists found that combining
peanut skin extract with maltodextrin allowed the peanut skin extract to be
added at a high enough level to increase the antioxidant activity without a
detectable bitter taste.
Dean's research constitutes another important example in creating value-added
products from food waste. There are a number of food waste products--including
coffee grounds and fruit peels--that contain these polyphenol compounds, which
could be extracted and processed to make functional food ingredients, including
healthier chocolates.
And what better way to celebrate International Chocolate Day than sink your
sweet tooth into a healthier milk chocolate bar