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Fruitilicious Chocolate, Gibbons Of The Opera

by Nader Heidari
September 3, 2012 | A version of this story appeared in Volume 90, Issue 36

Credit: Courtesy Of Stefan Bon
Sweet innovation: Bon and his team lower fat content via emulsion.
Stefan Bon poses with various chocolates and glassware filled with fruit juices.
Credit: Courtesy Of Stefan Bon
Sweet innovation: Bon and his team lower fat content via emulsion.

People all over the world enjoy chocolate for its taste, texture, and the characteristic “snap” it makes when broken. But, as with many confectionaries, those delightful properties come at a price: high fat and sugar content.

Fortunately, a team led by Stefan A. F. Bon at the University of Warwick, in England, has found a way to make chocolate healthier while retaining its beloved properties. The researchers infuse chocolate with fruit juice to replace some of its fat content (J. Mater. Chem., DOI: 10.1039/c2jm34233b). The method they use, called Pickering emulsion, suspends juice-filled droplets in the chocolate with small amounts of fumed silica and chitosan. These common food additives stabilize the emulsion.

Emulsions, which include mixtures of one liquid dispersed in another, are “widely used in the food industry,” Bon says. “For example, margarines and vegetable-fat spreads make use of water-in-oil emulsions in their formulation. We thought, ‘If low-fat spreads are possible, why not extend this to other products that use a fat matrix, such as chocolate?’ ”

By adding the juice, the researchers impart some of the flavors of fruit to the chocolate. If a plain chocolate taste is preferred, however, the team showed that replacing the fruit juice with a mixture of water and ascorbic acid does the trick.

The emulsion method also preserves the texture of the chocolate, the researchers say in their paper, because it allows the cocoa butter inside to retain its optimal crystalline form. This form, known as polymorph V, is responsible for the hardness of the product—and thus its snap—as well as its ability to melt in a person’s mouth.

The mixture needs to be slightly acidic for the Pickering emulsion to work, and liquids other than juice, such as tea, coffee, or flat soda, can be used to make the low-fat chocolate, Bon says. “We believe this opens a route to exciting chocolate confectionaries with innovative tastes.”

According to Bon, his team’s chocolate-making process is highly scalable, and the food industry has already expressed interest in the technology.

Credit: Shutterstock/C&EN
Opera singer: Gibbons have vocal skills similar to sopranos.
A gibbon in formal evening dress (white tie).
Credit: Shutterstock/C&EN
Opera singer: Gibbons have vocal skills similar to sopranos.

Speaking of sweet treats, scientists recently had some fun listening to the vocal stylings of apes that were under the influence of helium.

But this wasn’t for entertainment. The research team, led by Takeshi Nishimura of the Primate Research Institute at Kyoto University, in Japan, was trying to determine how primates vocalize. By analyzing the calls of gibbons that had inhaled helium, the researchers found that the animals use their voices in a manner similar to opera singers when they communicate (Am. J. Phys. Anthropol., DOI: 10.1002/ajpa.22124).

Helium, which increases sound velocity and changes resonance frequencies, makes human voices seem high and squeaky. But it also raises the pitch of gibbons’ voices, making the animals’ singing easier to study.

The researchers placed the animals in a partial helium environment and recorded their calls. What they found was that the gibbons use a vocal technique similar to that used by professional sopranos, amplifying high-pitched sounds and carrying their voices farther. The findings suggest that humans and gibbons share the same basic physiology for vocalization, which contradicts a common theory that humans evolved unique anatomical traits that led to complex speech.

The good news is that if Newscripts readers are feeling bad about their nonunique vocal anatomy, they can take solace in a low-fat piece of fruit-juice chocolate.

Nader Heidari wrote this week’s column. Please send comments and suggestions to


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