Food firms seek a high-fat feel

By Nicholas Robinson contact

- Last updated on GMT

Emulsifiers and stabilisers are being used to reduce fat and thicken products
Emulsifiers and stabilisers are being used to reduce fat and thicken products

Related tags: Fat content, Water, Egg, Emulsion

Making low-fat versions of high-fat food and drink is something scientists will strive to do better, despite criticism, says Nicholas Robinson

Key points

The food and drink industry’s initiative to drive down fat content, on the advice of government and non-governmental campaigners, took a hit when a new report warned consumers to avoid products labelled as low-fat.

The report, which was published in the Postgraduate Medical Journal(PMJ)​ last month (November), urged consumers to follow a Mediterranean-style diet, full of whole-foods, olive oil and oily fish.

On publication, Dr Aseem Malhotra, a cardiologist and lead author of the report, told BBC One’s Breakfast​ show that consumers should avoid low-fat and fat-free foods altogether, as they were usually higher in salt and sugar. So where does that leave the food scientists who are working on new emulsifiers and stabilisers to make low-fat products?

Originally, a rise in consumer demand for healthier products led manufacturers to urge scientists to find new ways of reducing fat in food and drinks, such as in bakery, yogurt, milk shakes, cheese, sauces and mayonnaises, without affecting mouthfeel or taste.

“Some of the first emulsifiers and stabilisers developed to reduce fat didn’t result in an appetising end product,”​ claims Peter Wilde, senior research scientist at the Institute of Food Research. “But, over the years, we’ve developed some great techniques to prevent mouthfeel and taste being affected,”​ he adds.

Emulsions in food are mixtures of oil and water. Oil doesn’t mix well with water and separates without a stabiliser, Wilde explains. Mayonnaise, for instance, is made from oil, egg yolk and vinegar. The yolk is an emulsifier and contains the phospholipid lectin, which allows the vinegar and oil to form an emulsion.

Removing some of the egg yolk to make a lower-fat mayonnaise results in fewer lectins in the final product, which prevents the oil and water from mixing well and eliminates the creamy mouthfeel mayonnaise has. Reducing oil to lower the fat content also changes the mouthfeel, because there’s less fat, he adds.

“Stabilisers, such as starch, are there to increase the viscosity of a product, which helps slow down the separating effect and increases the thickness and mouthfeel of a product, whether it’s full- or low-fat.”

Starch granules are predominantly produced from potatoes, but there’s an emergence of these coming from seeds such as amaranth and quinoa, he adds.

Fat, such as oil, must be replaced with something else once it is removed from a product like mayonnaise, Wilde points out. Oil can be removed from mayonnaise and replaced with water and the same consistency can be achieved by using a stabiliser. “However, the mouthfeel will be watery because the oil gives it that creamy quality,”​ he adds.

Biggest priority (Key points)

Maintaining texture and mouthfeel is the biggest priority on the manufacturer's list during reformulation, says Dr Dorotea Pein, deputy head of research and development at the stabilising and emulsifying systems company Hydrosol. “It’s the big issue that remains –  how to find a new stabilising system for existing end products that keeps the original mouthfeel and texture.”

Work carried out at Hydrosol has allowed manufacturers of yogurts and mayonnaises to produce low-fat varieties, with the same creamy and rich mouthfeel as a full-fat product, she says. “The functional systems are suitable for deli emulsions with a high fat content (70– 80%), but they can also be used for salad creams and dressings with a fat content between 40 and 70%.”

Another way to attain emulsification in a low-fat product is to use a water-in-oil-in-water (WOW) method says Kathy Groves, project manager of microscopy at Leatherhead Food Research.

“WOWs are essentially water globules in an oil sphere that are dispersed into water again,” ​she explains. “In short, you have the same surface area of oil exposed, but a lot less in real terms as the oil sphere is filled with water, which is fat-free.”

Having the same surface area of oil in a product ensures the consumer is getting the same mouthfeel as they would with a 100% oil globule, but with a lot less fat. Although they are effective in reducing fat content, they can't be used on everything, she adds.

WOW emulsions are more difficult to prepare and control when compared with a simple emulsion, because they are made from larger droplets. There are few food-grade emulsifiers and stabilisers suitable for use on the inner and outer of the droplets, Wilde says.

There are also regulations preventing manufacturers from using them in anything other than a dressing or mayonnaise, because the use of the emulsifier polyglycerol polyricinoleate (PGPRE476), which is used in WOWs, is only permitted in spreads, sauces and chocolate. “We had a company that was ready to use them on a food product, but regulations stopped them,”​ he says.

“But, we are looking for ways we can work around regulation and how we can push for a change.”

As well as offering manufacturers the ability to reduce fat, WOWs can also provide an answer to salt reduction, as the stability of the double emulsion is dependent on the presence of salt, Groves adds.

“By adding salt to the water inside the droplet, less salt then needs to be added to the external liquid because there's more surface area of salt within the globule,”​ she says.

But, it is also expensive to create WOWs because of the extra processing required, Groves says. “It’s a difficult process, but you can use conventional processing methods in the final product, so the cost doesn’t extend beyond making the WOW.”

However, both Wilde and Groves agree that finding ways to reduce the fat content of food with emulsifiers and stabilisers could have adverse affects for the consumer. “There’s the argument that lower-fat and lower-calorie foods don’t achieve what they set out to do,”​ claims Wilde.

Tricking the body (Key points)

By consuming a low-energy food, which your body thinks is high-energy, consumers could overcompensate and end up eating more of it, he adds. “Your body doesn’t like to be fooled like that.”

Although she doesn’t claim to be an expert on diets and nutrition, Groves says: “It’s possible that, if a consumer sees something is half-fat or low-fat, they could eat twice as much.

“People could see it as an excuse to eat more of a product – so instead of dolloping one tablespoon of full-fat mayonnaise on a plate, they could have three or four tablespoons of half- or low-fat mayonnaise.”

Despite worries that low- and reduced-fat products could have the opposite result, Groves and Wilde are certain demand for emulsifiers and stabilisers with properties to reduce fat will continue to rise.

This is something Steve Osborn, Leatherhead Food Research business innovation manager, also believes is on the cards. “We’ve got a number of projects running at the moment, which are commercially sensitive, but are very important to the sector.”

Despite reports, such as the one in the PMJ​, challenging the industry’s initiative to find ways of reducing fat content in food, the sector will continue to take up the mantle.

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