Background On Carbohydrates & Sugars
Carbohydrates and Sugars Carbohydrates are one of three basic macronutrients needed to sustain life (the other two are proteins and fats). They are found in a wide range of foods that bring a variety of other important nutrients to the diet, such as vitamins and minerals, phytochemicals, antioxidants, and dietary fiber. Fruits, vegetables, grain foods, and many dairy products naturally contain carbohydrates in varying amounts, including sugars, which are a type of carbohydrate that can add taste appeal to a nutritious diet. Carbohydrate Classification Carbohydrates encompass a broad range of sugars, starches, and fiber. The basic building block of a carbohydrate is a simple union of carbon, hydrogen, and oxygen. The chemical definition of a carbohydrate is any compound containing these three elements and having twice as many hydrogen atoms as oxygen and carbon. Sugars in Foods When people hear the word “sugar” they often think of the familiar sweetener in the sugar bowl. That sugar is sucrose and is the most familiar form of sugar to home bakers. But there are many types of sugars, which scientists classify according to their chemical structure. Sugars occur naturally in a wide variety of fruits, vegetables, and dairy foods. They can also be produced commercially and added to foods to heighten sweetness and for the many technical functions they perform, including: contributing to foods’ structure and texture, sweetening and flavor enhancement, controlling crystallization, providing a medium for the growth of yeast in baked goods, and preventing spoilage. The sweetening ability of sugar can promote the consumption of nutrient-rich foods that might not be otherwise be consumed. Some examples are a sprinkle of sugar added to oatmeal or adding sugar to cranberries in Continue reading >>
Stainsfile - Carbohydrates
Although a major part of histotechnology is based on the staining of proteins in one way or another, proteins are not the only biological material with which we are concerned. Both carbohydrates and lipids are significant in both healthy and disease states, and it is important that their demonstration be reliable. Before that is possible an understanding of the nature of the materials is necessary. This page discusses the structure of carbohydrates as they relate to human histology. It is not an exhaustive explanation but will provide the background for demonstrating these materials. Carbohydrates are carbon compounds with hydrogen and oxygen in a 2:1 ratio, from which the name is derived, i.e. watery carbon or hydrated carbon. The 2:1 ratio of hydrogen to oxygen is, of course, H2O, the formula for water. The term carbohydrate is also used to refer to compounds derived from these by oxidation or reduction, by the addition of amino, carboxyl and phosphate groups, or by their being linked with proteins and lipids. The basic unit for carbohydrates is a sugar. There are numerous examples of sugars, which are more properly called monosaccharides and have the general formula of Cn(H2O)n. The prefix mono means "one" or "single", while the word saccharide means it is a sugar, i.e. it is a compound composed of a single sugar. The ending ide in this context means "in the class of", so a monosaccharide is a compound composed of a single molecule of sugar and classed as a carbohydrate. In addition to "mono", other prefixes which denote numbers may be encountered. The prefix di means two, so a disaccharide is a carbohydrate composed of two sugar molecules, and tri denotes carbohydrates with three sugar molecules i.e. a trisaccharide. The word Oligosaccharide means "a few sugars" an Continue reading >>
Disaccharide - New World Encyclopedia
Sucrose, a common disaccharide, composed of one glucose molecule (left) and one fructose molecule (right). A disaccharide is a type of carbohydrate consisting of two monosaccharides (simple sugars) linked together by covalent bonds . Common nutritionally important disaccharides are sucrose , lactose, and maltose . Disaccharide is one of the four basic categories of carbohydrates, the others being monosaccharide, oligosaccharide , and polysaccharide . Monosaccharides, such as glucose , are the monomers out of which disaccharides are constructed. While the disaccharides sucrose, lactose, maltose, and cellobiose have the same chemical formula, C12H22O11, and all have at least one glucose molecule as part of their structure, they differ substantially in their properties. Even maltose and cellobiose, which are made up of two covalently bonded glucose units, differ due to the nature of the linkage, with maltose easily hydrolyzed to its monosaccharides in the human body whereas cellobiose cannot be digested. This reveals not only a complex coordination in nature, but also reflects on the diversity in creation. The general chemical formula for carbohydrates, C(H2O), gives the relative proportions of carbon , hydrogen , and oxygen in a monosaccharide (the proportion of these atoms are 1:2:1). In disaccharides (and oligosaccharides and polysaccharides), the molar proportions deviate slightly from the general formula because two hydrogens and one oxygen are lost during each of the condensation reactions that forms them. These carbohydrates have the general formula Cn(H2O)m. Carbohydrates are a class of biological molecules that contain primarily carbon (C) atoms flanked by hydrogen (H) atoms and hydroxyl (OH) groups (H-C-OH). The four categories of carbohydrates are classified by Continue reading >>
Milk Composition - Lactose
is a readily digestible source of glucose (energy) for the neonate. is digested by lactase enzyme in the neonate. is the major osmole of milk (the primary component that draws water into the gland). Lactose is the major carbohydrate in the milk of most species. Lactose is a disaccharide composed of the monosaccharides D-glucose and D-galactose, joined in a -1,4-glycosidic linkage. The chemical name for lactose is 4-0--D-galactopyranosyl-D-glucopyranose. It is essentially unique to milk, although it has been identified in the fruit of certain plants. Of the mammalian species where information is available, only some marsupials have an alternative sugar other than lactose, and those sugars are generally trisaccharides of glucose and galactose. Lactose plays a major role in milk synthesis. It is the major osmole in milk and the process of synthesis of lactose is responsible for drawing water into the milk as it is being formed in the mammary epithelial cells. Because of the close relationship between lactose synthesis and the amount of water drawn into milk, lactose content is the least variable component of milk. Lactose is a disaccharide composed of D-galactose and D-glucose. Lactose is not as sweet as other disaccharides such as sucrose (a glucose-glucose sugar), or the monosaccharides fructose or glucose. Lactose is cleaved to glucose and galactose in the intestine of the neonate by an enzyme activity called lactase (or -galactosidase). The galactose is then converted to another glucose by a different enzyme. Lactose is a major, readily digestible source of glucose which provides energy for the neonate. Lactose intolerance can occur in adult animals or animals who do not have lactase activity in their intestines. Aspects of lactose in milk will be discussed further in Continue reading >>
Carbohydrates
Carbohydrates (also called saccharides) are molecular compounds made from just three elements: carbon, hydrogen and oxygen. Monosaccharides (e.g. glucose) and disaccharides (e.g. sucrose) are relatively small molecules. They are often called sugars. Other carbohydrate molecules are very large (polysaccharides such as starch and cellulose). Carbohydrates are: a source of energy for the body e.g. glucose and a store of energy, e.g. starch in plants building blocks for polysaccharides (giant carbohydrates), e.g. cellulose in plants and glycogen in the human body components of other molecules eg DNA, RNA, glycolipids, glycoproteins, ATP Monosaccharides Monosaccharides are the simplest carbohydrates and are often called single sugars. They are the building blocks from which all bigger carbohydrates are made. Monosaccharides have the general molecular formula (CH2O)n, where n can be 3, 5 or 6. They can be classified according to the number of carbon atoms in a molecule: n = 3 trioses, e.g. glyceraldehyde n = 5 pentoses, e.g. ribose and deoxyribose ('pent' indicates 5) n = 6 hexoses, e.g. fructose, glucose and galactose ('hex' indicates 6) There is more than one molecule with the molecular formula C5H10O5 and more than one with the molecular formula C6H12O6. Molecules that have the same molecular formula but different structural formulae are called structural isomers. Glyceraldehyde's molecular formula is C3H6O3. Its structural formula shows it contains an aldehyde group (-CHO) and two hydroxyl groups (-OH). The presence of an aldehyde group means that glyceraldehyde can also be classified as an aldose. It is a reducing sugar and gives a positive test with Benedict's reagent. CH2OHCH(OH)CHO is oxidised by Benedict's reagent to CH2OHCH(OH)COOH; the aldehyde group is oxidised to Continue reading >>
Carbohydrates
There are roughly 92 naturally occurring elements on earth, but interestingly, only 4 (oxygen, carbon, hydrogen and nitrogen) make about 96% of the mass of the human body. These elements combine to form life-sustaining biomolecules, which can be divided into four groups: carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates, proteins, and lipids are used by cells as the building blocks for cells or for energy, while nucleic acids are the basis of the genetic material. Carbohydrates are the most abundant of the biomolecules. Each year the earth converts more than 100 billion metric tons of CO2 and H2O into carbohydrates. If we were to identify the most important carbohydrate molecule on the planet, in terms of its ability to sustain life, we would undoubtedly select the monosaccharide glucose. Without glucose, nearly all animal life as we know it could not exist. There are three major classes of carbohydrates; monosaccharides, disaccharides, and polysaccharides. This classification is based on how many "subunits make up the molecule. The name "saccharide" is derived from the Greek, meaning sugar. Monosaccharides are the simplest form of carbohydrates and are composed of a single molecule or subunit. The disaccharides are composed of two monosaccharides linked together, and polysaccharides are composed of 3 or more monosaccharides linked together. We will now examine each of these types of carbohydrates. The monosaccharides (mono = one, saccharide = sugar) are the basic subunits of carbohydrates. They contain from 3 to 7 carbons and have the general formula of (CH2O)n where n ranges from 3 to 7 (5 or 6 being the most common). For example, if n = 6, the formula for the monosaccharide would be C6H12O6 and if n = 5 the formula would be C5H10O5. Hopefully, it is Continue reading >>
Disaccharides
Maltose is a reducing sugar. Thus, its two glucose molecules must be linked in such a way as to leave one anomeric carbon that can open to form an aldehyde group. The glucose units in maltose are joined in a head-to-tail fashion through an -linkage from the first carbon atom of one glucose molecule to the fourth carbon atom of the second glucose molecule (that is, an -1,4-glycosidic linkage; see Figure 16.8 "An Equilibrium Mixture of Maltose Isomers" ). The bond from the anomeric carbon of the first monosaccharide unit is directed downward, which is why this is known as an -glycosidic linkage. The OH group on the anomeric carbon of the second glucose can be in either the or the position, as shown in Figure 16.8 "An Equilibrium Mixture of Maltose Isomers" . Figure 16.8 An Equilibrium Mixture of Maltose Isomers Lactose is known as milk sugar because it occurs in the milk of humans, cows, and other mammals. In fact, the natural synthesis of lactose occurs only in mammary tissue, whereas most other carbohydrates are plant products. Human milk contains about 7.5% lactose, and cows milk contains about 4.5%. This sugar is one of the lowest ranking in terms of sweetness, being about one-sixth as sweet as sucrose (see Table 16.1 "The Relative Sweetness of Some Compounds (Sucrose = 100)" in Section 16.3 "Important Hexoses" ). Lactose is produced commercially from whey, a by-product in the manufacture of cheese. It is important as an infant food and in the production of penicillin. Lactose is a reducing sugar composed of one molecule of D-galactose and one molecule of D-glucose joined by a -1,4-glycosidic bond (the bond from the anomeric carbon of the first monosaccharide unit being directed upward). The two monosaccharides are obtained from lactose by acid hydrolysis or the cata Continue reading >>
Ch 4 Carbohydrates Flashcards
A monosaccharide that joins with glucose to create lactose, one of the three common disaccharide. Also called milk sugar, a disaccharide consisting of one glucose molecule and one galactose molecule. Found in milk, including human breast milk. A disaccharide consisting of two molecules of glucose. Does not generally occur independently in foods but results as a by-product of digestion. Also called malt sugar. A disaccharide composed of one glucose molecule and one fructose molecule. Sweeter than lactose or maltose. A nutrient compound consisting of long chains of glucose molecules, such as starch, glycogen, and fiber. The process by which the breakdown of fat during fasting states results in the production of ketones. Substances produced during the breakdown of fat when carbohydrate intake is insufficient to meet enrgy needs. Provide an alternative energy source for the brain when glucose levels are low. A condition in which excessive ketones are present in the blood,causing the blood to become very acidic, which alters basic body functions and damages tissues. Untreated ketoacidosis can be fatal. THis condition is found in individuals with untreated diabetes mellitus. Also called alternative sweeteners; manufactured sweeteners that provide little or no energy. An estimate made by the Food and Drug Administration of the amount of a non-nutritive sweetener that someone can consume each day over a lifetime without adverse effects. 300 times sweeter than sucrose. Evidence suggests that saccharin may cause bladder tumors in rats surfaced in the 1970s. More than 20 years of scietific research have shown that saccharin is not related to bladder cancer in humans. Saccharin is used in foods and beverages and sold as tabletop sweetener. Saccharin is sold as Sweet 'N Low in the Continue reading >>
Disaccharides - An Overview | Sciencedirect Topics
Disaccharide is a carbohydrate, which is formed when two monosaccharides undergo a condensation reaction, with the elimination of a single molecule of H2O, from the functional groups. Tse-Chao Hua, ... Hua Zhang, in Freeze-Drying of Pharmaceutical and Food Products , 2010 Oligosaccharides, especially disaccharides, are usually used as protective agents because the disaccharide can be used as both the cryoprotective agents in freezing and the protective agents in drying process [77-80]77787980. Disaccharide can be classified as reducing disaccharide (lactose, maltose) and non-reducing disaccharide (trehalose, sucrose). However, the disaccharide will cause the Maillard reaction (protein browning reaction) and result in the deterioration of freeze-dried product in storage. Consequently, sucrose and trehalose are the most widely used protective agents [81, 82]. Disaccharides can be reducing (having a free carbonyl group) or nonreducing. In the latter case, the two component monosaccharides are linked at their respective anomeric centers, and therefore, the carbonyl group is not available for reaction. Disaccharides are named as glycosides where the aglycone is another monosaccharide. Reducing disaccharides are named as substituted monosaccharides (Figure 10). Sucrose (saccharose) is by far the most important disaccharide (See SUCROSE | Properties and Determination; SUCROSE | Dietary Importance; SUGAR | Sugarcane; SUGAR | Sugarbeet; SUGAR | Palms and Maples; SUGAR | Refining of Sugarbeet and Sugarcane). Lactose (See LACTOSE) occurs in the milk of mammals but very rarely in the plant kingdom. Trehalose (-d-glucopyranosyl -d-glucopyranoside) (nonreducing) occurs in mushrooms and other fungi. Maltose is formed during the mashing of malt (See MALT | Malt Types and Products; MAL Continue reading >>
Nutrition Chapter 4 Flashcards | Quizlet
Commonly called sugar; a monosaccharide or disaccharide such as glucose. The simplest of carbohydrates. Consists of one sugar molecule, the most common form of which is glucose. A carbohydrate compound consisting of two monosaccharide molecules joined together. The sweetest natural sugar; a monosaccharide that occurs in fruits and vegetables; also called levulose, or fruit sugar. A monosaccharide that joins with glucose to create lactose, one of the three most common disaccharides. Also called milk sugar, a disaccharide consisting of one glucose molecule and one galactose molecule; found in milk, including human breast milk. A disaccharide consisting of two molecules of glucose; does not generally occur independently in foods but results as a by-product of digestion; also called malt sugar. The anaerobic process in which an agent causes an organic substance to break down into simpler substances and results in the production of ATP. A disaccharide composed of one glucose molecule and one fructose molecule; sweeter than lactose or maltose. A type of chemical bond that can be digested by enzymes found in the human intestine. A type of chemical bond that cannot be easily digested by enzymes in the human intestine. A nutrient compound consisting of long chains of glucose molecules, such as starch, glycogen, and fiber. A complex carbohydrate consisting of long chains of glucose. A polysaccharide stored in plants; the storage form of glucose in plants. A polysaccharide stored in animals; the storage form of glucose in animals. The non-digestible carbohydrate parts of plants that form the support structures of leaves, stems, and seeds. The non-digestible forms of carbohydrate that are extracted from plants or manufactured in the laboratory and have known health benefits. The s Continue reading >>
Chapter 4 Carbohydrates
Commonly called sugar; can be either a monosaccharide (such as glucose) or a disaccharide The simplest of carbohydrates, consisting of one sugar molecule, the most common form of which is glucose A carbohydrate compound consisting of two sugar molecules joined together The sweetest natural sugar; a monosaccharide that occurs in fruits and vegetables also called levulose, or fruit sugar. A monosaccharide that joins with glucose to create lactose,one of the three most common disaccharides A five carbon monosaccharide that is located in the genetic material of cells A disaccharide consisting of one glucose molecule and one galactose molecule. It is found in milk, including human breast; also called milk sugar. A disaccharide consisting of two molecules of glucose. It does not generally occur independently in foods but results as a by-product of digestion; is also called malt sugar. A process in which an agent causes an organic substance to break down into simpler substances and results in the production of ATP. A disaccharide composed of one glucose molecule and one fructose molecule; is sweeter than lactose or maltose. A nutrient compound consisting of long chains of glucose molecules, such as starch, glycogen, and fibre. A complex carbohydrate consisting of long chains of glucose A polysaccharide stored in plants; the storage form of glucose in plants. A polysaccharide; the storage form of glucose in animals. Glycogen is not found in plants. The indigestible carbohydrate parts of plants that form the support structures of leaves, stems, and seeds The indigestible forms of carbohydrates that are extracted from plants or manufactured in laboratory and have known health benefits. The sum of dietary fibre and functional fibre Natural pectins, mucilages, and gums that absorb Continue reading >>
Disaccharide
Sucrose, a disaccharide formed from condensation of a molecule of glucose and a molecule of fructose A disaccharide (also called a double sugar or biose[1]) is the sugar formed when two monosaccharides (simple sugars) are joined by glycosidic linkage. Like monosaccharides, disaccharides are soluble in water. Three common examples are sucrose, lactose,[2] and maltose. Disaccharides are one of the four chemical groupings of carbohydrates (monosaccharides, disaccharides, oligosaccharides, and polysaccharides). The most common types of disaccharides—sucrose, lactose, and maltose—have twelve carbon atoms, with the general formula C12H22O11. The differences in these disaccharides are due to atomic arrangements within the molecule.[3] The joining of simple sugars into a double sugar happens by a condensation reaction, which involves the elimination of a water molecule from the functional groups only. Breaking apart a double sugar into its two simple sugars is accomplished by hydrolysis with the help of a type of enzyme called a disaccharidase. As building the larger sugar ejects a water molecule, breaking it down consumes a water molecule. These reactions are vital in metabolism. Each disaccharide is broken down with the help of a corresponding disaccharidase (sucrase, lactase, and maltase). Classification[edit] There are two functionally different classes of disaccharides: Reducing disaccharides, in which one monosaccharide, the reducing sugar of the pair, still has a free hemiacetal unit that can perform as a reducing aldehyde group; cellobiose and maltose are examples of reducing disaccharides, each with one hemiacetal unit, the other occupied by the glycosidic bond, which prevents it from acting as a reducing agent. Non-reducing disaccharides, in which the component mo Continue reading >>
Nutrition Chapter 4 Flashcards | Quizlet
commonly called sugar; can be either a monosaccharide (such as glucose) or a disaccharide the simplest of carbohydrates, consisting of one sugar molecule, the most common form of which is glucose a carbohydrate compound consisting of two sugar molecules joined together the sweetest natural sugar; a monosaccharide that occurs in fruits and vegetables; also called levulose, or suit sugar a highly sweet syrup that is manufactured form corn and is used to sweeten soft drinks, desserts, candles, and jellies a monosaccharide that joins with glucose to create lactose, one of the three most common disaccharides a five-carbon monosaccharide that is located in the genetic material of cells a disaccharide consisting of one glucose molecule and one galactose molecule. it is found in milk, including human breast milk; also called milk sugar a disaccharide consisting of two molecules of glucose. it does not generally occur independently in foods but results as a by-product of digestion; also called malt sugar a process in which an agent causes an organic substance to break down into simpler substances and results in the production of ATP a disaccharide composed of one glucose molecule and one fructose molecule; sucrose is sweeter than lactose or maltose a nutrient compound consisting of long chains of glucose molecules, such as starch, glycogen, and fiber a complex carbohydrate consisting of long chains of glucose a polysaccharide stored in plants; the storage form of glucose in plants a polysaccharide; the storage form of glucose in animals the non digestible carbohydrate parts of plants that form the support structures of leaves, stems and seeds the non digestible forms of carbohydrates that are extracted from plants or manufactured in a laboratory and have known health benefits t Continue reading >>
Chapter 4 Flashcards | Quizlet
contain hundreds to thousands of molecules consist of a single sugar molecule. Examples: glucose, fructose and galactose consist of two molecules of sugar joined together. Examples: lactose, maltose, and sucrose must abundant monosaccharide, that is the main source of energy for the brain and for all cells an monosaccharide that is the sweetest natural sugar, occurs naturally in fruits and vegetables. a monosaccharide that joins with glucose to create lactose a disaccharide that consists of one glucose molecule and one galactose molecule (found in milk) a disaccharide that consists of two molecules of glucose, and the sugar that results from fermentation during the production of beer and liquor products a disaccharide that is composed of one glucose molecule and one fructose molecule. carbohydrates that contain 3 to 10 monosaccharides an oligosaccharide that is composed of galactose, glucose, and fructose an oligosaccharide that is composed of two galactose molecules, a glucose molecule, and a fructose molecule consist of hundreds to thousands of glucose molecules a polysaccharide stored in plants, it is the storage form of glucose in plants a polysaccharide stored in animals, it is the storage form of glucose in animals type of fiber that dissolves in water and they are fermentable, that is, they are easily digested by bacteria in the colon type of fiber that doesn't dissolve in water and they cannot be fermented by bacteria in the colon Starts in the mouth, ceases in the stomach, picks up again in the small intestine, and finishes in the large intestine. An enzyme in the mouth that breaks down starch into smaller particles and eventually into the disaccharide maltose An enzyme that is secreted by the pancreas into the small intestine that continues to digest any rema Continue reading >>
Types Of Sugar
There are several types of sugar. This page mentions some specific sugars but concentrates on the main categories of sugars (monosaccharides and disaccharides) and the relationship between these and certain larger carbohydrates. What is Sugar ? Definition of sugar : A sugar is a carbohydrate that is soluble in water. Sugars are usually crystalline and have a sweet taste. Chemicals that are sugars often have names ending in "-ose". For example, note the suffix "-ose" in fructose, glucose, galactose, sucrose, lactose, and maltose. The word-ending "-saccharide" does not necessarily indicate that the chemical or group or category of chemicals is a sugar. See more examples of prefixes and suffixes used in biology - general biology, not all medical terms. The two main categories of sugars are monosaccharides and disaccharides. They are often described together with polysaccharides, and sometimes also oligosaccarides, due to the chemical relationship between these types of carbohydrates: Categories of sugars: Monosaccharides are simple ("unit") sugars. Disaccharides consist of molecules whose form is that of two monosaccharide molecules joined together. Categories of larger carbohydrate molecules formed from sugars: Oligosaccharides consist of molecules formed from a few (i.e. more than 2, but not "many") monosaccharide molecules joined together. Polysaccharides consist of molecules formed from many monosaccharide molecules attached together in the form of long chains. Courses covering the human digestive system and human diet and nutrition often include the following information about: Monosaccharides Disaccharides Oligosaccharides, and Polysaccharides 1. Monosaccharides Chemical Structure: Monosaccharides are also called "simple sugars". Monosaccharides are the common base u Continue reading >>
