How sweet it is

The widely publicised 'obesity epidemic' is driving a reduced-sugar trend across the whole spectrum of processed foods and drinks. Using sweetener blending, food processors are simultaneously improving their nutrition label by having less sugar and fewer kilojoules and reducing the ingredient cost for their product.

The canny consumer not only wants less sugar in his treats; he also wants low GI carbohydrates — the ones that produce only small fluctuations in blood glucose and insulin levels. There can be glycaemic benefits attained from blended sweeteners which appeal to the consumer even though the kilojoule content of the food has not substantially changed.

Sugar, or sucrose, serves as the standard for sweetness. The high-intensity sweetener sucralose is perceived to be about 600 times sweeter than sugar. Sucralose is used across a broad spectrum of the food, beverage and pharmaceutical industries. In addition to its sugar-like taste, sucralose is also extremely stable and maintains its sweetness even when exposed to high-temperature processing such as pasteurisation, sterilisation, UHT processing and baking. It remains stable in food products throughout extended periods of storage even at low pH and is non carcinogenic.

Sucralose was approved for use in Australia in 1993 and is the only sweetener that is actually created from sugar. In a patented multi-stage process, three of the hydroxyl groups in the sucrose molecule are selectively substituted with chlorine. This intensifies the sugar-like taste while creating a safe, stable low joule sweetener. Sucralose is well recognised as having a taste profile very close to that of sugar and this, together with its heat and acid stability, has made it a versatile and compatible sweetener for the beverage industry in particular and the food industry in general. Sucralose must be labelled as 'Sweetener (955)' or 'Sweetener (sucralose)'.

Aspartame is 180 to 200 times sweeter than sugar. Unlike sucralose, aspartame is metabolised but contributes slightly fewer kilojoules than sugar: 15.9 kJ/g. However, due to its high sweetness level, the energy it delivers at normal usage rates is negligible. The product is not heat stable and so is not suitable for use in many foods.

Aspartame is made by joining two amino acids, aspartic acid and phenylalanine, and a small amount of methanol. Products sweetened with aspartame must carry a statement on the label that they contain phenylalanine to alert those afflicted with phenylketonuria — a rare hereditary disease in which phenylalanine is not metabolised.

Food Standards Australia New Zealand (FSANZ) includes aspartame as a permitted additive in certain products, including carbonated soft drinks, under the FSANZ Food Standards Code.

If a high-intensity sweetener is used to replace some or all of the sugar in a product, the bulk space taken up by the sugar will have to be replaced. In beverages this is bonus time because this volume can usually be filled with the very cost-effective ingredient — water. However, in solid formulations bulking agents such as maltodextrin, polydextrose or a fibre will be needed.

It is critical to consider the full function of sugar in a formulation. In bakery, for example, sugar not only supplies a sweet flavour, it also contributes to browning, texture, crumb structure, volume and batter viscosity. When substituting sugar in a formulation, all of these criteria will need to be addressed. In beverages, sugar imparts a mouthfeel that is often appealing to consumers.

Many sweeteners exhibit synergy and so substitutions are not always straightforward mathematical exercises. Fructose, for instance, is detected very early while sucrose is slightly delayed. So if you are replacing sugar with fructose, you may need to use less fructose than you would expect if you based your substitution simply on the relative sweetness of fructose and sugar.

As consumers are selecting foods with low GI, low energy content, high fibre, pre- and pro-biotic activities, and health and wellness properties, it may well be time to review how you sweeten your products.