There are a lot more scientific aspects of sugar than simply being sweet.
Sugar has a range of unique properties that, either individually or in combination, make it an important ingredient in modern food production. With the pressure to reduce the sugar content in our foods, it is important to realise that sugar is very difficult to replace in food production. Sugar is one of the simplest structures in nature and, of all the staple products in our diet, has the broadest area of use and the most difficult product to replace.
Sweet taste
The primary functions of sugar in food products are to provide sweetness and energy. The first taste that we encounter (breast milk) is sweet, which may be why a sweet taste is appreciated and interpreted positively. Our inherent affinity for sweetness may also be explained by the fact that, in nature, sweet products are rarely poisonous, in contrast to many bitter substances. Sugar has a uniquely clean sweetness that is entirely free from off-taste or aftertaste.
Volume
Sugar can affect the weight and volume of food. Sugar increases the volume of bread because the yeast breaks down all or part of the sugar/syrup and transforms it into various components, including carbon dioxide. This carbon dioxide increases the volume of the bread and makes it more porous. In sponge cakes and cup cakes sugar creates bulk – in other words volume. If we were to stop using sugar in these products the amount of energy obtained from fat would increase making it less palatable.
Taste and aroma
An important property of sugar is that it can enhance tastes and aromas both above and below the sweetness threshold value. For example, a small amount of added sugar can enhance the taste of sour or bitter foods such as tomato sauce.
Texture
Texture is an expression of the sensation in the mouth. Sugar affects this by providing volume and consistency in many products such as bread, jam and beverages. In bread, sugar affects the volume of dough by speeding up the fermentation process, giving bread a more porous structure and softer crumb. In the manufacture of jam, marmalade and jelly, it is important to strike the correct balance between sugar, pectin and acid. Sugar’s ability to gel when combined with pectin is vital to the consistency of the product. Too much sugar may crystallise, while too little sugar will cause the gelling process to fail.
Shelf life
The preservative properties of sugar are exploited in products such as jams, juices and pickling solutions. Microorganisms need water in order to grow. They absorb water via the outer layer of the cell. If the concentration of sugar in food is raised to a certain level, all water is bound by the sugar. This reduces the amount of available water thus inhibiting the growth of microorganisms.
Colour
The Maillard reaction (a reaction between sugar and amino acids) gives rise to browning and flavouring in products such as bread, coffee, heated desserts and cakes. Caramelisation refers to the thermal decomposition of sugar and occurs when a sugar solution is heated to above 100°C. Caramel browning, a food colorant, is used in soft drinks, beer, confectionery products, soups and sauces. A certain content of sugar ensures that jams and marmalades retain their colour.
Moisture retention
In products such as biscuits and boiled sweets, which contain small amounts of water and large amounts of sugar, the relative moisture level is lower than the ambient humidity. Without protective packaging, these products will absorb moisture from the air and become soggy. The shelf life of bread is extended because sugar causes water to be retained for longer. Sugar helps to ensure the high quality of our food. Without sugar, jam would soon go off, ice cream would crystallise, and bread would lose its freshness and dry out. In addition, the taste of foods would be disappointing without the ability of sugar to round off and enhance natural taste components. Sugar has one or more unique, quality-enhancing properties, to offer almost all types of food production involving both solid and liquid foods.
