WOW! Fat reduction by stealth...

The first products containing new water-in-oil-in-water (WOW) fat replacers - novel emulsions with a significantly reduced fat content - could hit the market next year.

The technology, which uses a novel approach based on cross-flow membrane emulsification, enables manufacturers to create oil droplets that impart texture and creaminess without the same amount of fat, said Leatherhead Food International (LFI), which has been developing the technology in a joint project with the UK government's Department for Environment, Food and Rural Affairs (DEFRA).

The £700,000 project is scheduled to finish in September, although the first products are unlikely to be on the market until 2009 or 2010, predicted LFI's new chief executive Dr Paul Berryman.

He told FIHN: "The WOW project is proceeding well with some prototype mayonnaises and other products. We are very optimistic about it. It's a good way of reducing fat while maintaining taste and texture."

Project partners include Arla Foods, Puratos, Orkla Foods, McCormick UK, Danisco Emulsifers, Degussa Texturant Systems (now owned by Cargill) and the Institute of Food Research in Norwich, UK.

"It is important when you get these low-fat products that they taste good," said Berryman. "The advantage of the WOW emulsion is that if you can get the mayonnaise where the fat globules are the same size as in the full fat version, you get the same sort of mouthfeel."

In some traditional low fat products, where fat was replaced by starch, thickeners or gums, the result was not as palatable, he claimed.

WOW technology replaces the centre of the oil or fat droplet in a typical emulsion with water, so that fat droplets taste the same but don't contain as much fat.

The overall size and number and external characteristics of the droplets are exactly the same as in the standard emulsion.

WOW droplets are developed in a two-stage process, in which a water-in-oil emulsion is made in the conventional way using blenders or homogenisers.

The resulting mixture is then gently pumped through tiny holes in a ceramic tube into a flowing stream of water to create a multiple emulsion of water-in-oil droplets suspended in water, a 'WOW'.

The process is known as cross-flow emulsification (XME). The idea is that the oil droplets fool the mouth into believing that the mayonnaise or sauce is a regular, full fat product, although each oil droplet actually contains more water than oil.

Although the potential of WOW emulsions has long been recognised, they have not (to date) been manufactured on a large scale, owing to the difficulties in controlling emulsion formation under the high shear conditions experienced in conventional high-pressure homogenisers.