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When retailers start announcing the removal of all hydrogenated fats from their products, how do manufacturers respond and what are the technical implications? Rebecca Green finds out

It is pretty much an unwritten rule that any trend in the US will eventually find its way across the pond to the UK, and when it comes to removing trans fats from food, things are no different.

Following several high profile cases (Oreo cookies were taken to court over the issue), food manufacturers in America are now required by law to label the amount of trans fats in their products. Hardly surprisingly, the likes of Marks & Spencer and Tesco have been quick to follow suit - removing hydrogenated fat (a source of trans fats) from their ranges.

So what is so bad about trans fats? And what exactly is a trans fat, or a hydrogenated fat for that matter? Trans fatty acid (commonly known as trans fat) is formed when vegetable oil is hydrogenated (a chemical process) to make it solid at room temperature. Hydrogenated fat has long been used in products such as biscuits, cakes and margarines for its functional properties - it gives the desired structure and hardness while increasing shelf-life.

But is widely believed that trans fat clogs arteries and raises 'bad' cholesterol (LDL), while scrubbing away the 'good' (HDL) cholesterol that keeps arteries clean, which is why manufacturers have been working to remove it from their products (Kellogg, Walkers and United Biscuits, to name but a few).

There are now a number of trans-free alternatives to hydrogenated fats on the market and several fat modification techniques, although these may come at a price - be it a reduction in shelf-life or an increase in price.

One expert in the field believes it is 'relatively easy' to take hydrogenated fats out of certain foods, like biscuits and toffees, but harder for other products, such as something with a chocolate substitute coating. "There are ways of doing it but they have implications. For instance, they could lead to an increase in saturated fat or require more complex processes," he says.

A non-trans fat replacement for a chocolate substitute coating, for instance, could be real chocolate, but this would be more expensive.

According to the consultant, oils that have naturally occurring amounts of solid fat (such as palm or coconut oil) are potentially good substitutes. This is because the solid material can be concentrated using the process of fractionation - a physical separation of the different melting point fatty acids in a specific oil or fat, incorporating cooling or filtration .

The speciality oils and fats division of worldwide agricultural processor ADM has developed a low trans fat range using this process. "For products such as cake and pastry, margarines and the confectionery market, a specific functionality is required, which hydrogenated fats impart," said Phil Hogan, director, global oils and fats research. "ADM has replaced these hydrogenated fats with dry, fractionated fats in its new formulations by judicious blending and processing."

Furthermore, ADM claims these products perform as well as, if not better than, the hydrogenated versions.

liquid oils

Seed oils, like rapeseed, soyabean and groundnut, are other trans-free alternatives. However, because they are liquid they cannot be concentrated to make a solid fat. So the only way to use them is to completely hydrogenate them, creating a fully saturated fat.

"Although they will not contain trans fats, they will have a much higher melt in the mouth temperature and be quite un-palatable," says the consultant.

"In order to be used they have to undergo some further processing, which is where interesterification comes in - you interesterify them with other oils. But doing this means you have to declare them as hydrogenated, even though they don't contain trans fats."

The issue here then moves to consumers and whether or not they can distinguish between fully hydrogenated fat (trans-free) and partially hydrogenated fat (containing trans), which is unlikely, suggests the consultant, when most of their information comes from the "often sensationalist" popular press.

Following America's lead and labelling trans fats on packs will only help, he says, if consumers understand what a trans fat is in the first place. Indeed, the Food and Drink Federation highlights research by the Institute of Grocery Distribution, which shows consumers are more interested in total calories and total fat when it comes to information on a label.

So, what are the drawbacks of removing trans fats? According to oils and fats manufacturers, there should be no compromise in terms of taste, although shelf-life and cost can become a problem. There is also the issue of replacing the 'demon' trans fat with another 'baddie', albeit a lesser version - saturated fat. Yet to use an unsaturated fat means compromising on the structure of the product.

costly solution?

And cost, says the industry expert, depends on the application that the original hydrogenated fat was being used in and what the replacement is. "For instance, if the solution is complete hydrogenation followed by interesterification, you have introduced another process so it is likely to be more expensive. But if you can get away with the relatively simple palm oil-based alternative there may be no major cost implications," he says.

The consultant also suggests that replacing a hydrogenated fat with a non-hydrogenated fat may affect stability, while hydrogenated and non-hydrogenated fats can crystalise in different ways, so cooling or crystalisation conditions may need to be modified. Bob Burgess, technical manager at edible oils company AarhusKarlshamn UK points out that hydrogenated fats crystalise very fast so work well in high speed machinery, meaning certain industries may find it difficult to move away from hydrogenation.

However, the company has developed a range of low trans products for the foodservice and retail sectors, which it claims overcomes some of these problems. Prep ZT is a long life oil formulated for longer life frying and oxidative stability. The oil blend is non-hydrogenated and contains less than 1% trans fat.

Adams Food Ingredients is another company developing trans-free or low trans products including Adhealth - a range of low trans versions of its dairy ingredients. It is currently working to replicate the functional properties of hydrogenated fats in other products.

With so much work already being done by manufacturers to remove trans fats, is there much more room for improvement?

According to UK government data from the National Diet and Nutrition Survey, the actual intake of trans fats in the UK in 2001 was 1.3%, below the government recommended intake of 2%. "By now most of the oils and fats manufacturers have created their 'miracle' products and have been working on them since the whole issue first came about five years ago," says the consultant. "There is much less trans fat in food now than a few year years ago."

Unilever, Premier Foods, Nestlé and Cadbury Schweppes are among the many companies that have reformulated products to remove or lower trans fat and hydrogenated fat, with others sure to be not far behind.

But with McDonald's in the spotlight again over higher levels of trans fat in its French fries than it previously thought (8g in a portion of large fries not 6g) it seems the battle is not yet over. FM

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