Table sugar is sucrose, synthesised by plants such as sugar cane and sugar beet. Consumption of sucrose increased from the 19th century onwards, partly due to its widespread use in the agri-food industry. In , around million tonnes of sugar were produced worldwide, equivalent to 33 times the weight of the Great Pyramid of Giza in Egypt. Average consumption per capita varies greatly around the world, ranging from 15 kg in Africa to 53 kg in South America, according to the statistics for In Switzerland and in Europe in general, annual sucrose consumption went up from 3 kg per capita in to 40 kg in The agri-food industry has thus become the biggest consumer of sucrose and derivatives such as inverted sugar, obtained by hydrolysis using an enzyme called invertase, produced by yeasts.
In terms of chemistry, this runny syrup is an equimolecular mixture of fructose and glucose , meaning it contains equal amounts of both molecules. From a sensory point of view, it has great sweetening power and does not crystallise as easily as sucrose. It remains soft and smooth as it absorbs moisture and does not dry out. The bond is called a glycosidic linkage. What is notable about sucrose is that, unlike most disaccharides, the glycosidic bond is formed between the reducing ends of both glucose and fructose, and not between the reducing end of one and the nonreducing end of the other.
This linkage inhibits further bonding to other saccharide units. Since it contains no anomeric hydroxyl groups, it is classified as a non-reducing sugar.
The purity of sucrose is measured by polarimetry, through the rotation of plane-polarized light by a solution of sugar. Commercial samples of sugar are assayed using this parameter. Sucrose does not deteriorate at ambient conditions. Sucrose is generally extracted from sugar cane or sugar beet and then purified and crystallized.
Supersaturation is an unstable state. The sugar molecules will begin to crystallize back into a solid at the least provocation. Stirring or jostling of any kind can cause the sugar to begin crystallizing. The fact that sugar solidifies into crystals is extremely important in candy making. There are basically two categories of candies - crystalline candies which contain crystals in their finished form, such as fudge and fondant , and noncrystalline , or amorphous candies which do not contain crystals, such as lollipops, taffy, and caramels.
Recipe ingredients and procedures for noncrystalline candies are specifically designed to prevent the formation of sugar crystals, because they give the resulting candy a grainy texture. Large crystals of sucrose have a harder time forming when molecules of fructose and glucose are around.
Crystals form something like Legos locking together, except that instead of Lego pieces, there are molecules. A simple way to get other types of sugar into the mix is to "invert" the sucrose the basic white sugar you know well by adding an acid to the recipe.
Acids such as lemon juice or cream of tartar cause sucrose to break up or invert into its two simpler components, fructose and glucose.
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