Sugar

Types of carbohydrates

• Monosaccharides: glucose, fructose, galactose
• Disaccharides: sucrose, lactose, maltose
• Trisaccharides: raffinose (found in sugar beets)
• Polysaccharides: cellulose, glycogen, starch, and others

• Disaccharides are made up of two monosaccharide units; they can combine with water to form two molecules of monosaccharides.
• Trisaccharides are made up of three monosaccharide units.

Enzymes that break down different sugars

• Sucrase: sucrose
• Lactase: lactose
• Maltase, isomaltase: maltose

• Disaccharidase: disaccharides (sucrose, lactose, maltose)

Carbohydrates

• Any member of a large class of chemical compounds that includes sugars, starches, cellulose, and related compounds.
• Carbohydrates are produced naturally by green plants from carbon dioxide and water (through photosynthesis). Essential nutrients, they are the human body's main source of both quick and sustained energy.
• The three main classes of carbohydrates are monosaccharides, which are the simple sugars, e.g., fructose and glucose; disaccharides, which are made up of two monosaccharide units and include lactose, maltose, and sucrose; and polysaccharides, which are polymers with many monosaccharide units and include cellulose, glycogen, and starch.

Sugars

• Types of carbohydrates that are readily soluble in water, colorless, odorless, usually crystallizable, and sweet.  Sugars are distinguished from other carbohydrates such as starch, cellulose, and glycogen.

Glucose

• A white crystalline sugar, somewhat less sweet-tasting than sucrose (table sugar), found in fruits and honey.
• Glucose is the major source of energy in animal metabolism.
• It requires no digestion prior to absorption into the bloodstream.

• A monosaccharide, glucose can be obtained by hydrolysis of a variety of more complex carbohydrates, e.g., maltose, cellulose, or glycogen.
• It's commercially made from cornstarch.
• Glucose present in urine may be a symptom of diabetes.
• Dextrose is a synonym for glucose.

Fructose

• A simple sugar found in honey and fruit. Sweeter than sucrose.
• Fructose is a carbohydrate with the same formula as glucose, but with a different structure.

• An equimolar mixture of fructose and glucose, called invert sugar, is obtained by the breakdown of sucrose and is the major component of honey.
• Levulose is a synonym for fructose.
• Fructose is a low-glycemic sweetener.

Sucrose

• Common table sugar, a white, crystalline solid with a sweet taste. Common names, which indicate the natural source, include cane sugar, beet sugar, and maple sugar.
• Upon hydrolysis sucrose yields an unequal mixture of glucose and fructose. Sucrose is extracted chiefly from sugarcane and sugar beet and is commonly called cane sugar. When heated to temperatures above 180° C s(356° F), sucrose becomes the amorphous, brown, syrupy substance called caramel.
• Sucrose is obtained from the juice of sugar cane or sugar beets and from the sap of the sugar maple. It is evaporated to give first a brownish liquid, called molasses; further evaporation yields a brownish sugar. The color, due to impurities, is removed by charcoal used in the refining process.
• After harvesting, sugarcane stems are crushed and shredded between rollers. The juice is extracted, treated, filtered, evaporated in a partial vacuum, and heated to form a thick syrup rich in sugar crystals. A centrifuge forces the molasses out of the syrup. The molasses is processed into a number of other products, while the remaining raw sugar is refined and reduced to crystals. Sugar from the roots of the sugar beet is processed in a similar manner. Sugar beet sugar is identical to sugarcane sugar.
• Sucrose is a high-glycemic sugar.

Lactose

• A white crystalline sugar formed in the mammary glands of all lactating animals and present in their milk. A disaccharide lactose can be broken down by hydrolysis into glucose and galactose. When milk sours, the lactose in it is converted by bacteria to lactic acid. Lactose is less sweet-tasting than sucrose and, unlike sucrose, is not found in plants and is not fermented by ordinary yeast.
• Lactose falls about halfway between sucrose and fructose on the glycemic index.

Maltose

• A crystalline sugar involved in brewing beer.  Maltose can be produced from starch by hydrolysis in the presence of diastase, an enzyme found in malt. A disaccharide, maltose is hydrolized to glucose by maltase, an enzyme present in yeast. The glucose thus formed can be fermented by another enzyme in yeast to produce ethanol.

• Honey is an invert sugar.
• It's a combination of fructose, sucrose, glucose, and maltose.
• It's not a low-glycemic sweetener.

Starch

• A white, odorless, tasteless carbohydrate powder. It plays a vital role in the biochemistry of both plants and animals. Made in green plants by photosynthesis, it is one of the main forms in which plants store food. Animals obtain starch from plants and store it as glycogen. Both plants and animals convert starch to glucose when energy is needed. Commercially, starch is made chiefly from corn and potatoes. Corn syrup and corn sugar made from cornstarch are widely used to sweeten food products. Starch is also used to stiffen laundered fabrics and to size paper and textiles.

Cellulose

• A carbohydrate of high molecular weight that is the chief constituent of the cell walls of plants. Raw cotton is 91% cellulose. Other important natural sources are flax, hemp, jute, straw, and wood. Cellulose has been used to make paper since the 2d cent. a.d. Cellulose derivatives include guncotton (fully nitrated cellulose), used for explosive; celluloid (the first plastic); and cellulose acetate, used for plastics, lacquers, and fibers such as rayon.

Glycogen

• Highly branched polymer of glucose that is made and stored in the liver and muscle cells of humans and the higher animals and in the cells of lower animals. During short periods of strenuous activity, energy is released in the muscles by direct conversion of glycogen to lactic acid.

Hypoglycemia

• Abnormally low level of blood glucose, the body's chief energy source (hence the term low blood sugar). It is most often caused by an oversecretion of insulin from the pancreas triggered by stress, exercise, fasting, or disorders of the adrenal or pituitary glands, liver, or pancreas; in persons with diabetes it may result from an overdose of insulin. Symptoms range from weakness, fatigue, shakiness, and anxiety to mental disturbances, convulsions, and coma. Acute episodes are relieved by ingestion of glucose or sucrose. Long-term treatment involves control of causative factors and diet regulation.
• Abnormally low level of sugar in the blood. Symptoms include weakness, shakiness, nervousness, anxiety, faintness, and marked personality changes. Hypoglycemia is the result of hyperinsulinism (excess of insulin), caused by an overdose-in the case of persons with diabetes mellitus-or by overproduction. Reactive, or functional, hypoglycemia is the most common type. It occurs especially among people under emotional stress and can be controlled by lowering carbohydrate intake.

Diabetes

• Chronic disorder of carbohydrate metabolism involving insulin. Insulin-dependent diabetes (Type 1), which affects children, is usually caused by a deficient secretion of insulin and is treated by insulin injections. Noninsulin diabetes (Type 2), which affects adults, results from the inability of the cells in the body to respond to insulin and can usually be controlled with diet regulation and oral hypoglycemic (sugar-lowering) drugs. Symptoms of diabetes are elevated sugar in the urine and the blood, excessive urination, thirst, hunger, weakness, weight loss, and itching. Diabetes can lead to vascular disease, kidney disease, hypertension, and blindness. Uncontrolled diabetes leads to diabetic acidosis: ketones in the blood, confusion, unconsciousness, and possible death.

Liver

• Of the liver's many digestive system functions, the storage of glucose (in the form of glycogen) is particularly important.

Pancreas

• Glandular organ of the digestive system that secretes digestive enzymes and hormones. In humans, the pancreas is a yellowish organ that lies crosswise beneath the stomach and is connected to the small intestine at the duodenum. It produces trypsin, amylase, and lipase-enzymes essential to the digestion of proteins, carbohydrates, and fats, respectively. Small groups of cells in the pancreas, called islets of Langerhans, contain several types of specialized cells: alpha-2 cells, which produce the hormone glucagon; beta cells, which produce the hormone insulin; and alpha-1 cells, which produce somatostatin, all of which regulate blood-sugar levels.

Insulin

• Hormone secreted by the islets of Langerhans in the pancreas. A protein of 21 amino acids in two cross-linked chains, insulin was the first protein to be sequenced (1951), and its synthesis was reported by several groups in the mid-1960s. Insulin was also one of the first products to be manufactured using genetic engineering. In general, insulin acts to metabolize glucose (sugar). It also increases protein synthesis in muscle. Insufficient insulin in the body results in diabetes, a condition treated by the administration of insulin or drugs that stimulate insulin secretion.

Glucagon

• Polypeptide hormone secreted by the islets of Langerhans in the pancreas. It tends to counteract the action of insulin, i.e., it raises the concentration of glucose in the blood, essentially by promoting glycolysis. Glucagon also has a role in converting adenosine triphosphate to cyclic adenosine monophosphate.

Glycolysis

• Process in all higher animals and most microorganisms in which glucose is broken down. Beginning with a single molecule of glucose, glycolysis is a series of chemical reactions requiring eleven different enzymes and eventually yielding two molecules of lactic acid, which then enter the citric acid cycle. The reactions of glycolysis also generate the high-energy substance adenosine triphosphate. Glycolysis is the primary means by which many anaerobic organisms obtain energy.

• Glucose derivative of corn starch, popular in the brewing, canning, and baking industries because it lends texture and body to these types of products.

• Takes the processing of corn syrup one step further, by converting much or all of the glucose to fructose; the resulting product is much sweeter than sucrose, allowing less of it to be used.
• Main nutritive sweetener in the soft drink industry.
• Sometimes labeled as glucose-fructose or glucose/fructose in Canada.
• Has a high glycemic value, that is, it causes the insulin to surge.
• High fructose corn syrup is found in numerous products and is not the same as a product that contains only fructose, which is a low-glycemic sweetener.
• There is some controversy as to the safety of consuming large amounts of this sweetener over time.

• Mannitol, sorbitol, and maltitol occur naturally in fruits.
• Sometimes used as a substitute for sucrose.
• Maltitol does not raise glucose, therefore insulin, levels and is useful for diabetics and low-carbers.

• Because they are metabolized by the body more slowly than sucrose, they are useful in foods for people following special diets, such as a diabetic diet.
• Add bulk and texturizing to food such as chewing gum and hard candies.
• Xylitol is a normal intermediate product in the metabolism of carbohydrates in fruits and vegetables.

• If large amounts are eaten (50g or more, at one time), they can cause stomach pain and diarrhoea.

• Glucose/fructose is a generic term for high fructose corn syrup (HFCS).
• High fructose corn syrup is often noted as "glucose-fructose" in Canada, presumably because the laws on how to label aren't as strict.

• Glucose syrups and isomerized glucose syrups, singly or in combination, where the fructose fraction does not exceed 60 per cent of the sweetener on a dry basis.

• Sugar or glucose-fructose, singly or in combination.

• Glucose syrups and isomerized glucose syrups, singly or in combination, where the fructose fraction exceeds 60 per cent of the sweetener on a dry basis.

The numbers are in respect to white bread being 100. Multiply the GI’s by 0.7 to convert to glucose = 100.  Lower numbers are better.

• Fructose 32
• Lactose 65
• Honey 83
• High fructose corn syrup 89
• Sucrose 92
• Glucose 137
• Maltodextrin 137
• Sugar, White 142
• Maltose 150

• Saccharin, Aspartame, and Acesulfame-K do not have any energy value and (supposedly) do not affect blood glucose levels.
• In general, those sweeteners that provide calories (nutritive sweeteners) are thought to offer little or no benefit to people with diabetes.
• When eaten in large quantities many of these products have unwanted side effects, especially diarrhoea.

Saccharin

• 200 to 700 times sweeter than sucrose.
• Has a bitter aftertaste at high concentrations.
• Derived from petroleum.

• Sold as a white powder for use as a table-top sweetener, and used in a variety of foods such as beverages, jams, and baked goods.
• Despite controversy over its safety, it remains on the generally-recognized-as-safe (GRAS) list.
• The human body cannot break it down, so it does not produce an insulin response.

Acesulfame-K

• 200 times sweeter than sucrose.

• Marketed as Sunette, the sweetener was approved by the Food and Drug Administration (FDA) in 1988 for limited use in products such as chewing gums and dry beverage mixes; approval for additional food uses are pending.

Sucralose

• 600 times sweeter than sucrose.
• The only alternative sweetener made from sugar.

• Derived from sugar through a patented, multi-step process that creates an extremely stable substance unable to be absorbed by the human body; it is excreted in the urine virtually unchanged.
• Manufactured under the name Splenda, sucralose can be found as a tabletop sweetener and in a variety of products including desserts, confections, and nonalcoholic beverages.
• Approved by the FDA in 1998.

Aspartame

• 200 times sweeter than sucrose and has no aftertaste.
• Has a flavor similar to sucrose, and also functions as a taste intensifier and enhancer.
• A packet of this sweetener is equivalent in sweetness to two teaspoons of sugar (32 calories) and has four calories.

• Commercially available as Equal, Nutrasweet and Spoonful (a product designed to measure like sugar), aspartame is composed of two naturally occurring amino acids (the building blocks of protein) - phenylalanine and aspartate.
• After nearly two decades of safety testing, aspartame was approved by the FDA in 1981 for use in a variety of products, as a table-top sweetener and in carbonated beverages.
• In July 1993, approval was made for use in hard and soft candies, baked goods and mixes, nonalcoholic beverages and malt beverages.
• There is a great deal of controversy over the safety of this sweetener.
• About 10% of the aspertame sweetener breaks down into methanol, which is known to be toxic; supposedly, people get far less aspartic acid, phenylalanine and methanol from aspartame than from normal consumption of natural foods.
  

Cyclamates

• 30 times sweeter than sugar, with little aftertaste.

• Banned in the U.S. in 1970 after a study where it was fed to rats in combination with saccharin implicated it as a possible cancer-causing agent. (Subsequent research failed to replicate this finding.)
• Cyclamates have been pending re-approval by the FDA since 1982, and are approved for use in 40 other countries and Canada; use of cyclamates in Canada is restricted to table-top sweeteners and pharmaceuticals.