What is dextrose in sweets?

Dextrose is the name you will often see on food labels for glucose, the sugar that travels around your body in your blood. It is a natural sugar, found in fruit and honey, and it is one of the building blocks of ordinary table sugar. In sweets it adds sweetness and bulk.

Why it is called dextrose

Glucose was discovered in grapes by the German chemist Johann Tobias Lowitz in 1792, and he showed it was different from cane sugar. It is still sometimes called grape sugar, because drying grape juice produces crystals of it.

The name dextrose was proposed by the chemist Friedrich August Kekulé. It comes from the Latin dexter, meaning right, because a solution of glucose turns polarised light to the right. Today the two words mean the same thing: dextrose tends to be used on food labels and in nutrition, and glucose in biology.

How it is made

Dextrose is made from starch. The starch is broken down with pressurised steam, under carefully controlled acidity, and then enzymes break it down further into glucose. The starch used depends on where it is made: corn starch in the United States and Japan, potato and wheat starch in Europe, and tapioca starch in tropical countries.

The same process, stopped earlier, makes glucose syrup, one of the basic ingredients of sweets. Corn syrup is one common source of purified dextrose, and these syrups are used to make hard sweets, ice cream and jam.

Dextrose and table sugar

Table sugar is sucrose, a sugar made of glucose and fructose joined together. Dextrose is glucose on its own. It is less sweet than table sugar: pure dextrose is about 80 per cent as sweet. Glucose syrups are useful to sweet makers for more than sweetness: in marshmallows, for example, they help stop other sugars crystallising, and they can add body and reduce sweetness.

Where you will find it in sweets

Dextrose is a common ingredient in chewing gum, where it adds bulk and sweetness alongside sugar and corn syrup. Dubble Bubble, the bubble gum Walter Diemer invented in 1928, lists sugar, dextrose and corn syrup as its first ingredients. In the United States, Pixy Stix are a dextrose rich version of sherbet powder. For the story of bubble gum, see Walter Diemer, the accountant who invented bubble gum

Dextrose and low blood sugar

Because it is the sugar the body uses directly, glucose raises blood sugar quickly. Low blood sugar, or hypoglycaemia, is treated by eating or drinking something sugary, such as glucose tablets or gel, apple juice, soft drinks or lollipops, provided the person is conscious and able to swallow. A 2017 review of the research found glucose tablets were 12 per cent more likely to work within 15 minutes than sugar from ordinary foods. In an emergency, when someone cannot eat, dextrose can be given straight into a vein. For more on sweets and low blood sugar, see why are Jelly Babies used for low blood sugar?

It is still sugar, though, and it counts towards the sugar in your diet: see how much sugar is in sweets?

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