Sugar production

Sugar is the generalized name for a class of chemically-related sweet-flavored substances, most of which used in food. They are carbohydrates, composed of carbon, hydrogen, and oxygen. There are various types of sugar derived from different sources. Simple sugars are called monosaccharides and include glucose (also known as dextrose), fructose and galactose.

The table or granulated sugar most customarily used as food is sucrose, a disaccharide (in the body, sucrose hydrolyses into fructose and glucose). Other disaccharides include maltose and lactose. Chemically-different substances may also have a sweet taste, but are not classified as sugars. Some are used as lower-calorie food substitutes for sugar described as artificial sweeteners.

Sugars are found in the tissues of most plants, but are only present in sufficient concentrations for efficient extraction in sugar caneand sugar beet.

The world produced about 168 million tons of sugar in 2011. The average person consumes about 24 kilograms of sugar each year (33.1 kg in industrialized countries), equivalent to over 260 food calories per person, per day. In most parts of the world, sugar is an important part of the human diet, making food more palatable and providing food energy. After cereals and vegetable oils, sugar derived from sugar cane and beet provided more kilocalories per capita per day on average than other food groups.

Sugar beet is the tuberous root of which containing a high proportion of sucrose. The crop is harvested mechanically in the autumn and the crown of leaves and excess soil removed. The roots do not deteriorate rapidly and may be left in a clamp in the field for some weeks before being transported to the processing plant. Here the crop is washed and sliced and the sugar extracted by diffusion. Milk of lime is added to the raw juice and carbonatated in a number of stages in order to purify it. Water is evaporated by boiling the syrup under a vacuum. The syrup is then cooled and seeded with sugar crystals. The white sugar that crystallizes out can be separated in a centrifuge and dried. It requires no further refining.

Sugarcane is a perennial grass. The crop is harvested mechanically or by hand, chopped into lengths and conveyed rapidly to the processing plant. Here, it is either milled and the juice extracted with water or extracted by diffusion. The juice is then clarified with lime and heated to kill enzymes. The resulting thin syrup is concentrated in a series of evaporators, after which further water is removed by evaporation in vacuum containers. The resulting supersaturated solution is seeded with sugar crystals and the sugar crystallizes out, is separated from the fluid and dried. The crystals of raw sugar have a sticky brown coating and either can be used as they are or can be bleached by sulphur dioxide or can be treated in a carbonatation process to produce a whiter product.

Granulated sugars are used at the table to sprinkle on foods and to sweeten hot drinks and in home baking to add sweetness and texture to cooked products. They are also used as a preservative to prevent micro-organisms from growing and perishable food from spoiling as in jams, marmalades, and candied fruits.

Milled sugars are ground to a fine powder. They are used as icing sugar, for dusting foods and in baking and confectionery.

Brown sugars are granulated sugars with the grains coated in molasses to produce a light, dark sugar. They are used in baked goods, confectionery, and toffees.

The five largest producers of sugar in 2011 were Brazil, India, the European Union, China and Thailand. In the same year, the largest exporter of sugar was Brazil, distantly followed by Thailand, Australia and India. The largest importers were the European Union, United States and Indonesia. At the current time, Brazil has the highest per capita consumption of sugar, followed by Australia, Thailand, and the European Union.