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Sucrose

physical science Maturity 11-13 Next article →

Sucrose is a disaccharide, which is a type of sugar made of two smaller subunits. These two parts are glucose and fructose.

Sugar 2xmacro
Sugar 2xmacro

It is the primary component of white table sugar. Plants, algae, and cyanobacteria produce it naturally. They use sucrose to store energy gathered during photosynthesis. This sugar is found in many plant parts, including roots, fruits, and nectars. For example, pineapple and apricot are fruits where sucrose is the main sugar. In contrast, fruits like grapes and blueberries contain almost no sucrose.

A Bowl of Sugar 2
A Bowl of Sugar 2

In the natural world, sucrose acts as an energy storage molecule. The two subunits, glucose and fructose, are joined by a specific chemical bond. This is called a glycosidic linkage. Specifically, it is an ether bond between the first carbon of glucose and the second carbon of fructose. This unique connection is different from most other disaccharides. Because the bond forms at the reducing ends of both sugars, it prevents further bonding. This makes sucrose a non-reducing sugar. This chemical structure also prevents it from reacting spontaneously with other molecules in cells.

Sugar 2xmacro
Sugar 2xmacro

Humans extract sucrose from two main plant sources. Sugarcane is grown in tropical regions. Sugar beets are grown in temperate climates.

Sucre blanc cassonade complet rapadura
Sucre blanc cassonade complet rapadura

The refining process for both is quite detailed. In sugar mills, workers crush sugarcane to create raw sugar. This raw sugar is shipped to factories for further refining. In beet factories, the beets are processed directly into refined sugar. The refining steps involve washing raw crystals and dissolving them into a syrup. This syrup is filtered and passed over carbon to remove color. Finally, the syrup is boiled under a vacuum to create pure sucrose crystals. These crystals are clear, odorless, and sweet.

Raw sugar closeup
Raw sugar closeup

Scientists have a long history of studying this molecule. The term "sucrose" was coined in 1857 by the English chemist William Allen Miller. The name combines the French word for sugar with a chemical suffix. In 1860, the French chemist Marcellin Berthelot named it saccharose. While that name is now considered obsolete, it was once common. For a long time, scientists could not recreate sucrose in a laboratory. This changed in 1953 when Raymond Lemieux and George Huber succeeded. They synthesized sucrose from acetylated glucose and fructose.

Raw sugar closeup
Raw sugar closeup

Sucrose has several distinct physical forms used in cooking and industry. White refined sugar is nearly pure, often reaching a purity higher than 99.7 percent. It is sold in various grain sizes. Granulated sugar has a grain size of about 0.5 mm. Caster sugar is much finer at 0.35 mm and dissolves quickly. Powdered or confectioner's sugar is a very fine dust, measuring only 0.060 mm.

Würfelzucker -- 2018 -- 3564
Würfelzucker -- 2018 -- 3564

There is also coarse sanding sugar used for decoration. Brown sugar is different because it contains molasses. This gives it a darker color and a stronger flavor.

Sa brownsugar
Sa brownsugar

Some sugar is even made into cubes by mixing granulated sugar with syrup.

Würfelzucker -- 2018 -- 3564
Würfelzucker -- 2018 -- 3564

Chemical reactions can change how sucrose behaves. When sucrose is heated, it can undergo thermal degradation. This process is used in cooking to create caramel. If sucrose is mixed with potassium nitrate, it creates a fuel called rocket candy. This fuel is used to propel amateur rocket motors. Sucrose can also be broken down through a process called hydrolysis. This process splits the disaccharide back into glucose and fructose. This happens very slowly on its own, but enzymes like sucrase make it happen rapidly. In the human body, gastric acidity performs this hydrolysis during digestion.

Sugar 2xmacro
Sugar 2xmacro

Understanding sucrose involves precise scientific measurements. The industry uses degrees Brix, or °Bx, to measure sugar concentration. This measures the mass ratio of dissolved sugar to water. For instance, a 25 °Bx solution contains 25 grams of sucrose in 100 grams of liquid. Scientists also use polarimetry to check purity. This method measures how a sugar solution rotates plane-polarized light. The specific rotation for sucrose is +66.47 degrees. Globally, the scale of sugar production is massive. In 2017 alone, the world produced about 185 million tonnes of sugar.

A Bowl of Sugar 2
A Bowl of Sugar 2
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🖼️ Images & Media (7)
File:Raw sugar closeup.jpg
Raw sugar closeup.jpg
File:Sugar_2xmacro.jpg
Sugar_2xmacro.jpg
File:Würfelzucker_--_2018_--_3564.jpg
Würfelzucker_--_2018_--_3564.jpg
File:A_Bowl_of_Sugar_2.jpg
A_Bowl_of_Sugar_2.jpg
File:Sucre blanc cassonade complet rapadura.jpg
Sucre blanc cassonade complet rapadura.jpg
File:Sa brownsugar.jpg
Sa brownsugar.jpg
File:Sugar 2xmacro.jpg
Sugar 2xmacro.jpg
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