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What exactly do we mean by sugar? Most people would answer by describing the white granulated sugar found on the meal table. That is however only part of the answer. Table sugar is sucrose and is only one of a number of different sugars all of which belong to the carbohydrate group of basic energy foods. CARBOHYDRATES Sugars are a major form of carbohydrate and are found in probably all green plants. They occur in significant amounts in most fruits and vegetables.
There are three main simple sugars sucrose, fructose and glucose. Sucrose is in fact a combination of fructose and glucose and the body quickly breaks it down into these separate substances. Lactose, another sugar very similar to sucrose, is an important component of milk and other dairy foods. To understand the role of sugar as a foodstuff, one needs to look more closely at carbohydrates. These are the basic energy foods which provide most directly the energy that all green plants produce and store. The two main carbohydrate categories are sugars and starches.
The sugars are the simpler of the two. Starch molecules can be considered as sugar molecules strung together (rather loosely) in chains. These, more complex starch carbohydrates, are found in potatoes, rice, bread, pasta and cereals. All sugars and starches are broken down and used by the body as glucose, which is the bodys primary energy source. THE NEED FOR ENERGY All food energy derives originally from the sun and its effect on green plant life. The suns energy acts upon the green chemical chlorophyll in the leaves of plants to produce sugars and starches from the carbon dioxide in the atmosphere and the water from the roots.
These carbohydrates (starches and sugars) act as the plants food and energy supply. The scientific name for the process is photosynthesis. The human body which has a constant need for energy cannot obtain it from photosynthesis and so it is largely dependent on the carbohydrates (energy) that are derived from plants. Energy for a balanced human diet is supplied by carbohydrates, fats and proteins. A BALANCED DIET A balanced diet can (and should) come from a variety of different foods, calculated to give the desired levels of carbohydrates, proteins, fats, vitamins and minerals. Nutritional scientists advocate that carbohydrates should provide at least 50 % of our energy requirements i.
e. energy not alone for physical activity but also for all other continuous processes such as breathing, thinking, eating and sleeping. All carbohydrates are acted upon by the body to provide the necessary glucose supply for energy. The brain in particular must have a constant supply of glucose. If this is not readily available from ingested carbohydrate stores, then the body will have to increasingly turn to a process known as glycogenesis. This describes the production of glucose from non-carbohydrate sources such as fats and proteins.
SUGARS ROLE Starches provide the larger part of our carbohydrate needs. The sugars which nature provides alongside the starches in our food supply have also a very special role to play in human metabolism. For primitive man the sweet taste probably acted as a signal that the food was safe to eat. For modern man sugar is used to improve the palatability of many foods and can thereby encourage a more varied diet. For example, a grapefruit is an excellent source of Vitamin C which most people find too bitter to take without sugar.
Likewise, many breakfast cereals may be lacking in taste and may actually contain too much fibre unless some sugar is added to them Sugar Production All green plants make sugars. Through water and minerals in the soil and absorbing carbon dioxide (CO 2) from the air they produce chlorophyll. Chlorophyll uses light energy from the sun to combine CO 2 and water (H 2 O) to produce sugar. Plants also release Oxygen (O 2) into the air as a by-product. The process by which plants make sugar is photosynthesis from the Greek photo (light) and synthesis (putting together) Consumption Sugars are extremely important energy providers and flavour enhancers, whether in crystal form or in the cells of fruit and vegetables. Sugar plays a large nutritional role in our diets along with other carbohydrates, fats, proteins, fibre and micro-nutrients such as vitamins and minerals. 3.
Combustion Carbohydrate fuels (sugar, starch C 6 H 12 O 6) are burned up to give energy while at the same time releasing CO 2 and H 2 O. Error! Bookmark not defined. Sugar as an Energy Provider Every activity undertaken by human beings requires energy. The main sources of energy are carbohydrates (sugars and starches), fats and proteins.
Energy is measured in calories (or kiloJoules: 1 kJ = 4. 18 cal). For example a twelve year old boy requires about 2500 calories per day and a 12 year old girl about 2000 calories per day. Sugar as a commodity in its own right can be traced back several thousand years in China and India. A definite reference dates to 510 B.
C. when soldiers of the Persian Emperor Darius saw sugar cane growing on the banks of the River Indus. They called it the reeds which produce honey without bees. Much later it was grown in Persia and the Arabs took it to Egypt.
The word sugar is itself derived from an Arabic word. Sugar cane, to which all the earliest references refer, is a member of the grass family. It can grow up to 15 feet tall, with leaves at the top and a hollow stalk filled with a sweet juice or sap from which sugar can be extracted. A perennial tropical plant, it grows best in very warm climates. It is ready for harvesting after 10 to 20 months. Alexander the Great (356 - 232 B.
C. ) introduced sugar to the Mediterranean countries, from whence it spread down the east coast of Africa. SUGAR PRODUCTION By 600 A. D. the practice of breaking up the sugar cane and boiling it to produce sugar crystals was widespread. Six hundred years later, when Marco Polo visited China, he saw flourishing sugar mills. The mediaeval world was quick to recognise the difference sugar made to food, and a flourishing trade built up.
By the middle of the fifteenth century there were plantations in Madeira, the Canary Islands and St. Thomas, and they supplied Europe with sugar until the sixteenth century, when manufacture spread over the greater part of tropical America, followed in the next century by the development of sugar exports from the West Indies. Old records show that raw cane sugar was being refined in Dublin and Belfast in the middle of the seventeenth century. SUGAR BEET The other main source of sugar, sugar beet, although known as a sweet vegetable, was not used as a commercial source of sugar until the second half of the eighteenth century, when Margraf, working in Berlin, discovered a technique for extracting sugar from the beet.
This was later further developed by his pupil Award. Its further development was due in large part to the activities of two major historical figures, Nelson and Napoleon. Nelsons victory at Trafalgar in 1805 was followed by a blockade which cut off continental Europe from cane sugar. Napoleon, hearing of the new technique for extracting sugar from sugar beet, decided in 1811 that sugar beet was henceforth to be the source of sugar for Europe.
Thereafter cane sugar and beet sugar developed in parallel and often in competition. SUGAR DEMAND From the Middle Ages on sugar was for several centuries a commodity a little like pepper in price and usage. King Henry III of England had difficulty in obtaining as much as 3 lbs for a banquet in 1226. It was given as a special present to lovers in Southern France and elsewhere. It formed the basis of trade between Barbary (Morocco) and England in Henry Viii's day. The demand for sugar was one of the major reasons for the slave trade for two centuries or more.
During the whole of the eighteenth century it was the direct or indirect cause of many an Anglo-French naval battle in the Caribbean. Demand for sugar increased with the growing world population, and even faster, perhaps because improving technology made its production cheaper. In the 1830 s when the world population was 1, 000 million, recorded sugar production was 800, 000 tonnes a year. By 1900 it was 8 million tonnes.
By the mid- 1970 s with a world population in excess of 4, 000 million, world production of sugar was about 80 million tonnes, almost equally divided between sugar cane and beet. Today annual production stands at 115, 000, 000 tonnes. HISTORY OF SUGAR IN IRELAND In Ireland it became obvious to those interested in creating a home-based sugar industry to supply this countrys needs, that refining sugar from cane grown in the tropics was not cost- effective. Other vegetables contained natural sugar. It was a matter of finding which one produced sugar in the greatest quantity and of the most usable quality. Beet turned out to be the answer to the problem.
Sugar is therefore unique in that it comes from two main sources sugar-beet and sugar-cane a fact that means it can be grown in almost every country in the world. In the early nineteenth century, beet was grown in the west of Ireland, and beet juice extracted in Achill. The system there was to crush the root with a big millstone drawn by a horse. The crushed pulp was then spread, with layers of straw, in a press which squeezed out the juice. It was then boiled in a large sheet-iron pan until it reached the crystallizing point, after which it was cooled and drained. Although the first attempts to create an Irish sugar industry were snuffed out by the taxes imposed in the Act of Union, it was nevertheless clear that making our own sugar would be a vital part of our development as an agricultural nation, and so experiments continued towards the end of the last century designed to produce the highest yielding form of sugar beet.
On the foundation of the new state in 1922, Ireland was quite advanced in sugar beet research, and in December 1925, on flatland's by the River Barrow, engineers began to mark out the ground for what was to become the Carlow sugar factory. That factory was to prove that high quality sugar could be produced economically in Ireland from home-grown natural raw material. Later, the State took over the Carlow factory, and in the mid-thirties, built others at Mallow, Thurles and Tuam. CONCLUSION During its long history sugar has been, as well as the cause and prize of wars, an object of political activity.
The industry has often been early on the list for expropriation in newly independent countries and has been nationalized in many cases. There are many reasons for this. Sugar is an attractive commodity which also provides a simple means of collecting taxes. It supplies a livelihood for countless thousands of people throughout the globe. And in a world whose population is rapidly growing it is important, because the sugar cane and the sugar beet are respectively the most efficient plant fixers of solar energy among tropical and temperate zone vegetation. The cane is four times as effective as any other tropical plant in terms of production of harvest able dry matter per hectare per year, and the beet is twice as productive as any temperate zone plant.
Put another way, it requires on average of only 0. 07 hectares to fix solar energy to the equivalent of 1 million kilocalories of energy in the form of sugar. All other forms of edible energy require more, with beef at the top end of the scale, needing 7. 7 hectares over 100 times as much land as sugar. And, as fossil fuels are limited, sucrose, both as a renewable raw material, and as the pure organic chemical most cheaply produced on a world-wide scale, may well in future become additionally a feedstock for the production of such materials as plastics and detergents. Sugar as a commodity in its own right can be traced back several thousand years in China and India. A definite reference dates to 510 B. C.
when soldiers of the Persian Emperor Darius saw sugar cane growing on the banks of the River Indus. They called it the reeds which produce honey without bees. Much later it was grown in Persia and the Arabs took it to Egypt. The word sugar is itself derived from an Arabic word.
In Ireland today, there are some 90, 000 acres under sugar beet. This present acreage yields some 1. 6 million tonnes of beet which is converted into approximately 200, 000 tonnes of sugar. Technological advances have made planting and harvesting sugar beet particularly efficient. Seeds are sown encased in a pellet of fertiliser which not only protects it from pests but also assists it through its early development. From mid September to early January harvesting occurs.
A mechanical harvester lifts the root, cleans it and cuts the leaves off for usage as animal feed. The beet is then taken to one of Irelands two sugar processing factories. Once inside the factory, the beet is weighed and tested for sugar concentration. The farmer is paid relative to the tonnage of clean beet delivered on a sliding scale of sugar content.
The beet is either unloaded dry and stored in open-top silos or washed from the lorry with powerful water jets and transferred to production. Here the beet is thoroughly cleaned again, removing remaining clay and sand. The beet is then thinly sliced and passed through a diffuser (see Diffusion) which uses hot water to draw out the sugar. The resultant liquid called raw juice, is black in colour and has around 14 % of sugar content.
The remaining pulp is mixed with molasses, dried and sold as animal feed. The juice is then purified to remove further non-sugars. This is achieved by adding lime and carbon dioxide, which causes many of these non-sugars to be removed from the solution. After this process, the juice is concentrated through evaporation where much of the water is boiled off.
This leaves the juice with about 60 % sugar content. The sugar is crystallized out of solution in a final evaporation under reduced temperature and pressure. The contents are then discharged into large holding vessels where the sugar crystals are allowed to grow to their final size. After this the crystals are separated from the syrup by a centrifugal (see Centrifuge) process (spinning through perforated screens).
The separated syrup (molasses) is used mainly for animal feed. The crystals are dried, screened and cooled before being stored in large silos before packaging. The total time from initial beet washing to white sugar is about 12 hours. INTRODUCTION The production of Irish sugar begins with the sowing of the sugar beet in the spring.
In the early years of the industry the seed was sown by hand into pre-made and fertilized drills. Later in the season, the multi-germ beet seed had to be hand thinned. Weeds had also to be removed by hand, there being no chemical control. By the 1990 s, however, with the aid of the new multi-purpose machinery specially designed by Irish Sugar Plc. , the labour intensive methods of the past had been totally eliminated.
In addition, a new beet seed has been developed which requires no thinning and which is sown encased in a pellet of fertiliser which not only protects it from pests but also assists it through its early development stages. In Ireland today there are some 90, 000 acres under sugar beet in any given year. In order to sow this acreage four billion seeds are required annually. HARVESTING THE BEET The harvesting of the sugar beet, or the campaign as it is known, starts around the end of September and continues until mid-January. Production of sugar from the beet is a continuous process. Once the campaign starts it continues 24 hours a day, seven days a week, until all the beet is processed.
The present acreage yields some 1. 6 million tonnes of beet which is converted into some 200, 000 tonnes of sugar. Harvesting is also done by mechanical methods. Todays mechanical harvester is particularly ingenious. It not alone takes the root out of the ground, it also cleans it and cuts off the top of the plants. The leaves are a valuable source of animal feed equal in value per acre to one acre of turnips.
The beet is taken by lorry from the harvested field to one of Irelands two sugar processing factories. For the duration of the campaign a steady stream of lorries / tractors can be seen on the roads to the sugar factories WEIGHING AND SAMPLING Once inside the factory grounds the lorries drive over a weighbridge where their gross weight is automatically measured. At the same time a sample of the particular load is taken to determine the sugar percentage and the amount of tare in the overall load. Tare may consist of clay, stones, beet tops, etc. It is deducted from the gross weight of the load in order to determine the net weight of clean beet delivered. The farmer is paid a predetermined price per tonne of clean beet delivered based on a sliding scale related to sugar content UNLOADING There are two systems of unloading dry unloading and wet unloading.
When dry unloading, the beet is conveyed from the lorry by a series of conveyed belts to open air silos where it is stored. In wet unloading the beet is washed from the lorry by means of a powerful jet of water. Beet is transferred from the silos to the factory by means of water. En route to the production process, stones and grass are removed in a series of stone and grass catchers. The beet is thoroughly washed before processing to remove all traces of clay and sand DIFFUSION The actual sugar is inside the beet and has to be extracted. In order to extract the sugar the beet is first cut up into elongated slices.
Sugar is then extracted from the beet by diffusing (see Diffusion) it out with hot water. This is done in a large vessel specially designed for this purpose. Beet slices are fed in continuously at one end and hot water at the other end. A solution of sugar emerges from one end and the exhausted beet slices emerge from the other.
The exhausted beet slices, or pulp, are mixed with molasses then dried and sold as an animal feed. The solution now left to continue for the rest of the process is referred to as the raw juice. This contains about 14 % sugar and is black in colour SATURATION At the diffusion stage other substances are extracted from the beet as well as the sugar. But before sugar can be produced in a white crystalline form it is necessary to remove as many of these non-sugars as possible. This part of the process is referred to as juice purification. The main raw materials used in the purification are lime and carbon dioxide gas which are got by burning limestone in a kiln.
These substances are added to the juice causing non-sugars to be precipitated out of the solution. The solid material is then filtered off. After juice purification the juice has a light yellow colour EVAPORATION The purified juice is a sugar solution containing approximately 14 % sugar and 1 % non-sugars. It is now necessary to concentrate this solution. This is done by boiling off water from the solution in large vessels known as evaporators.
On entering the evaporators, the solution contains approximately 14 % sugar. On leaving the evaporators it contains approximately 60 %VACUUM PANS In order to turn the sugar into a crystalline form it is now necessary to evaporate still more water. This is done at a reduced temperature and pressure in large vessels known as vacuum pans. Syrup is fed to the pans and as the water is evaporated off, the crystals of sugar begin to grow. When the pan is full it contains about 50 tonnes of a mixture of sugar crystals in syrup. The contents are then discharged into large holding vessels known as crystallizersCENTRIFUGALS The next step in the operation is to separate the sugar from the syrup.
This is done in automatically controlled machines known as centrifugals. In them the syrup is spun off and the sugar crystals remain. The wet sugar is then dried, screened, cooled and sent to large bulk storage silos each of which can contain up to 50, 000 tonnes. The syrup from the centrifugals still contains a lot of dissolved sugar.
This syrup is put back through two more boiling stages in order to extract still more sugar. The final syrup from which it is no longer practical or economical to extract more sugar is known as molasses. It contains some sugar together with non-sugars which were not removed at the juice purification stage. It is mainly used for animal feed. The total time from beet washing to white sugar is about twelve hours.
Depending upon sugar content of the beet, 100 tonnes of beet will give approximately 12 - 14 tonnes of sugar and 3 - 4 tonnes of molasses.
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