Sweet ambition

We've come a long way from saccharin, the first non-food sugar substitute, discovered somewhat by accident back in 1878. Manufacture of this sweetener with a bitter aftertaste began in 1901, and it remained more or less the only 'artificial' sweetener until the 1950s, when along came cyclamates (discovered in 1937), breathing new life into saccharin's future with taste improvements created through synergistic cyclamate/saccharin blends.

And then came a whole lot more. The commercial development of non-caloric and reduced-caloric foods and beverages began to accelerate from the late 1950s, sparked initially by the increased versatility of the saccharin/cyclamate blends, and eventually by the commercial development of other zero-calorie products such as aspartame (discovered in 1965) and acesulfame K (discovered in 1967), which also have added benefits when used synergistically with each other, and with other sweeteners.

While saccharin has a sweetening power 300-600 times that of sugar, cyclamate is only about 30 times as sweet, but has solubility, heat stability, flavour advantages and other characteristics that opened the way to using non-sugar sweeteners in a wider variety of foods; but there were also questions about the carcinogenicity of cyclamate, such that it was banned from use in some countries and even now has limits on its usage levels in the EU.

Aspartame first came to market in the US in the 1980s as Nutrasweet. Meanwhile, Ajinomoto and others took out patents refining the original process from the 1970s onwards. Developed by Hoechst, acesulfame K had further advantages including a cleaner taste and better heat stability, so that it could be used in yet wider food applications and certain cooking processes. It is now marketed exclusively under the Sunett brand by Nutrinova, a former subsidiary of Hoechst.

Following aspartame's impressive commercial success, US Nutrasweet and French collaborators have come up with a derivative of aspartame called neotame, said to have a clean, sweet taste and to be 8,000 times as sweet as sugar.

The only other major high intensity sweetener of note is sucralose, unique in that it is the only high intensity sweetener made from ordinary sugar (sucrose) rather than from chemical intermediates. The result of an intensive research programme carried out by Tate & Lyle in the 1970s, sucralose is seen as the most versatile of all.

While high intensity sweeteners are now finding use in many food applications, their biggest market remains in drinks, where their role is simply to replace the sweetening effect of sugar, any deficits in bulking being made up with water. But as health considerations have come to dominate the industry in recent years, the potential for replacing sugar in confectionery, desserts, jams and preserves, canned fruit, dairy products, ice cream and baked goods has grown immensely.

In general, polyols have about half the calorific value of sugar, but all have a laxative effect, so that there are limits in the EU to the levels permitted in foods.

But polyols do not brown during cooking processes, and are not reactive with starch and protein as sugar is during cake baking. Dr Julian Cooper, head of food science at British Sugar, says that if you tried to bake a cake in which sugar was replaced with polyols, you would get a dense, flat, unappetising result. Others would say that a combination of erythritol and crystalline mannitol could provide a sponge cake with improved volume and shelf-life compared to the classic sucrose-based item.

Meanwhile, concepts such as gut health, blood sugar levels and glycaemic index (GI) have over recent years brought to the fore several further possibilities for the bulk replacement of sucrose in foods. These include lower-calorie, lower-sweetness or slower-digesting sugars (tagatose, trehalose, isomaltulose), starch derivatives such as polydextrose, maltodextrins, and the so-called 'resistant' starches, as well as soluble fibres and prebiotics such as inulin. Collectively, this diverse group of products has a huge range of functionalities, and some have little or no sweetness at all.

By using them in appropriate combinations - and in combination with other sweeteners, even high-intensity ones - a great deal can be achieved.

The future

With concerns over obesity rising, it's clear that the sugar content of all foods will continue to receive close attention. Nutrition labelling is also set to change, to become yet more informative and exacting.

Meanwhile, all food additives are under constant safety scrutiny, and the European Food Safety Authority is set to re-evaluate the safety of all sweeteners for the EU. At the same time, consumers and food producers are becoming more concerned with 'clean' labels. We should expect, therefore, that pressures on both sugar and its replacement additives will be unrelenting, on several fronts. This will include demands for more benign processing methods.

If fact, compared to its substitutes, white sugar is not very processed at all - just extract it from a natural raw material, add heat, remove water and crystallise it if you want it in solid form. It is naturally white, and the colours of brown sugars are achieved by adding back byproducts from the refining process.

And sugar's GI is actually lower than you think. While the starch in cereal products, for instance, has a GI around 100, the GI of sucrose is 65 (because of the way it is metabolised, compared to glucose at 100), and that of chocolate is only around 50. If sugar is added to cereals, it actually lowers the GI, British Sugar's Julian Cooper insists, pointing out that it is possible to formulate low sugar versions of cakes that are in fact higher in calories or GI than the real thing. Consumers beware!

Meanwhile, most polyols are still made by nickel-catalysed hydrogenation; for example, isomalt is made by hydrogenating isomaltulose in a process pioneered by Südzucker in 1957. Long considered a good thing, hydrogenation is now regarded as a bad thing in the edible oils and fats industry. We are also seeing the first signs of certain polyols being made completely by natural processes that are more acceptable to informed consumers.

While sucralose is made from sugar, the process currently used by Tate & Lyle involves chlorination with phosgene. In the long run, this may be seen as no better than hydrogenation.

market trends

With the time for approvals of new food products so long and the risk of failure so high, no one is really expecting many - if any - new products to replace sugar. And in 2006 Holland Sweetener Company left the aspartame market, saying it had become unprofitable because of oversupply. According to reports, the price of the sweetener has declined by 75% since Nutrasweet's patents expired in 1992. Meanwhile, in the wake of the EU's sugar reforms, Nordzucker has closed its Innosweet subsidiary to concentrate on its core business. Maybe other companies will follow where they see sugar and sugar replacers as conflicting businesses.

When patents run out or do not apply, companies resort to branding for market differentiation. One recent example of this is Cargill's current attempts to get its branded isomaltulose (Xtend Sucromalt) approved for food use in the EU following its approval in the US.

Further out, we should perhaps bear in mind that glycerine - a natural, syrupy polyol made by splitting fat for soap production, and previously prohibitively priced for many food applications - is now available in unprecedented volume at low prices (as low as sugar) as a result of biodiesel production. It already has food status and has been used in foods for many years; it has a bitter-sweet flavour, but not as bad as saccharin. Who's betting we will see more of it, to add to food formulators' repertoires?

This will most probably be in combination with other products, though; because the taste quality of a sweetener - or the eating quality of a bulk sugar replacer - is only really meaningful in the context of a food product, and the consumer is the always the ultimate judge.

The author is indebted to Kath Veal of Leatherhead Food International for clarification of various points in the preparation of this article.