A Willy Wonka-style discovery by scientists at the University of Warwick could lead to “skinny” chocolate bars made with fruit juice instead of fat.

Scientists at the university have come up with a way to cut half the fat from the confectionery while retaining its “chocolatey” feel.

The secret is juice in the form of micro-bubbles that preserve a texture that is firm to bite yet melts in the mouth.

Lead researcher Dr Stefan Bon said: “We have established the chemistry that’s the starting point for healthier chocolate confectionery.

“This approach maintains the things that make chocolate ‘chocolatey’, but with fruit juice instead of fat. Now we’re hoping the food industry will take the next steps and use the technology to make tasty, lower-fat chocolate bars and other candy.”

Using fruit juice or diet cola to make chocolate also reduced overall sugar content.

The technology works with all kinds of chocolate - dark, milk and white, said Dr Bon. The Warwick team has made chocolate infused with apple, orange and cranberry juice.

“Fruit juice-infused candy tastes like an exciting hybrid between traditional chocolate and a chocolate-juice confectionery, “ Dr Bon added. “Since the juice is spread out in the chocolate, it doesn’t overpower the taste of the chocolate. We believe that the technology adds an interesting twist to the range of chocolate confectionery products available.

“The opportunity to replace part of the fat matrix with water-based juice droplets allows for greater flexibility and tailoring of both the overall fat and sugar content.”

Chocolate contains healthy antioxidant plant chemicals known as flavonoids, but also high levels of unhealthy fat and sugar.

A two ounce serving of top-quality dark chocolate contains 13 grams of fat - a fifth of the total daily amount recommended for someone consuming 2,000 calories a day, said Dr Bon.

Much of this fat is the saturated variety that is bad for the heart and arteries.

Chocolate is technically an emulsion - a combination of ingredients that normally would not mix together - of cocoa butter and water or milk combined with cocoa powder.

Dr Bon’s team used fruit juices to form a Pickering emulsion, named after the British chemist Percival Pickering who in 1907 discovered a new way to stabilise emulsions using solid particles.

The research was presented at the annual meeting of the American Chemical Society in New Orleans in America.