Technology & Science·Q&A

Fat in chocolate can be reduced with electric field, say researchers

What if there was a way to make chocolate a little bit less fatty without losing its creamy texture? CBC Radio science columnist Torah Kachur looks at a new technique that may change chocolate for the better.

New process may allow for chocolate with less fat, but all the flavour

A challenge in reducing the fat in chocolate has been maintaining its texture. But researchers at Temple University think they've done that, by applying an electric field to liquid chocolate. (Denis Balibouse/Reuters)

Despite all the claims that chocolate is healthy, we all know it really isn't that good for us. Sure, raw chocolate is full of good antioxidants. But there's still all that fat and sugar in the processed chocolate most of us eat.

So what if there was a way to make chocolate a little bit less fatty without losing its creamy texture? CBC Radio science columnist (and self-professed chocoholic) Torah Kachur looks at a new technique that may change chocolate for the better.

How can chocolate be improved?

In one way, really — reduce the fat. Most chocolate bars are about 40 per cent fat, which gives them their delicious creaminess. But they're often full of the harmful types of fat that we generally want to avoid.

There have been attempts to try to reduce the fat content of chocolate while still preserving its chocolatey goodness. But those have failed royally, because as soon as you remove lots of the fat, you get a chunky, marbly mess. 

Other attempts to try to swap out the cocoa butter with a fat substitute of some kind have worked in the U.S. But some of those substitutes, like olestra, haven't been approved by Health Canada and agencies in other countries. So that's not a viable alternative.

Removing fat from chocolate through traditional means would lead to liquid too thick for manufacturers. But a new process using an electric field may allow for chocolate that has less fat, but the right viscosity. (CBC)
You can have lower-fat chocolate by just removing some of the cocoa butter used in the manufacturing process, but then you are faced with another dilemma — it won't be chunky, but it won't flow very well either. 

And manufacturers rely on the nice liquid texture of melted chocolate to let it flow through their machinery. Reduce fat and you get clogged pipes.

What solution does the latest research offer?

This is new work out of a physics lab at Temple University in Philadelphia — partially funded by chocolate giant Mars — that figured out there is a way to reduce the fat in chocolate, but still allow it to flow through the machines.

The strategy is to apply an electric field — a process called electrorheology — in the same direction the chocolate flows through a pipe. The idea is to reduce the viscosity — or, in other words, increase the speed at which the chocolate flows.

How does that work?

We always think of chocolate as a solid, but it's really a liquid suspension. When it's melted, there's the liquid cocoa butter as well as a suspension of cocoa, sugar and milk solids that are floating in that melted fat.

If there are too many of those solid particles in the fat, the whole mix becomes too viscous... unless you change the shape of the solid particles floating around.

That's what the electric field does. Cocoa particles are roughly spherical, but when they are subjected to an electric field they stretch out from a sphere into more of an oval shape. In other words, they become more narrow and can flow better. 

Not only that, when you subject melted chocolate to this electric field, the little chocolate particles form a nice long chain that can snake its way through the pipes.

That means this technique can produce lower fat chocolate that doesn't clog the pipes.

How does it taste?

Rongjia Tao, the lead researcher at Temple University, thinks that it's tastier than the original.

I'm a bit sceptical. I consider myself a chocolate connoisseur, and think it would be tough to take the fat out without me noticing. That being said, those who have had the opportunity to taste it have said that it's good, and has a nice strong cocoa flavour without leaning too bitter. 

And there's a bit of a last step to making the low-fat chocolate taste like chocolate. When the electric field is applied, those chains of chocolate particles form. Those seem to persist after the chocolate is hardened, which could account for flavour differences.

The researchers propose to shake the liquid chocolate vigorously after it passes through the electric field to break up those chains and restore the regular suspension of chocolate. If that works, I'm optimistic.

When will we see this on the market?

It's still in very much the prototype phase. The researchers actually built their own machine to make their few batches of the chocolate.  

Researchers think applying an electric field to chocolate could reduce its fat content by up to 20 per cent. (The Pioneer Woman)
It's a bit unusual to have an electric field orient the way it does for chocolate — normally when you do electrorheology, you have the electric field perpendicular to the direction of flow. So it was a bit tricky to get it in the same direction as the flow of the liquid — chocolate in this case.

The machine the researchers invented was found to be energy efficient, and reduced conventional chocolate fat percentages of Hershey and Mars chocolates by 10 per cent. But their calculations found that theoretically, they should be able to reduce the fat content by up to 20 per cent.

Their paper does conclude with "We are expecting a new class of healthier and tastier chocolate soon."

And we should temper our expectations. Even if it does match my expectations for taste, and reduce the fat, I would still say it's never going to be healthy.

ABOUT THE AUTHOR

Torah Kachur

Science Columnist

Torah Kachur is the syndicated science columnist for CBC Radio One. Torah received her PhD in molecular genetics from the University of Alberta and now teaches at the University of Alberta and MacEwan University. She's the co-creator of scienceinseconds.com.

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