Biological Sciences
Simple Carbohydrates
Simple carbohydrates, also known as simple sugars, are composed of one or two sugar units. They are quickly digested and absorbed by the body, leading to rapid spikes in blood sugar levels. Common sources of simple carbohydrates include fruits, milk, and processed sugars like table sugar and high-fructose corn syrup. Due to their rapid digestion, excessive consumption of simple carbohydrates can contribute to health issues like obesity and diabetes.
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10 Key excerpts on "Simple Carbohydrates"
eBook - PDFNutrition
Science and Applications
- Lori A. Smolin, Mary B. Grosvenor(Authors)
- 2016(Publication Date)
- Wiley(Publisher)
Carbohydrates made up of only one sugar unit are called monosaccharides (mono- means one), those made up of two sugar units are called disaccharides (di- means two), and those made up of more than two sugar units are called polysaccharides (poly- means many). Simple Carbohydrates Monosaccharides and disaccharides are classified as Simple Carbohydrates or sugars. Fruits, vegetables, and milk are whole food sources of Simple Carbohydrates. The sugars we add to food such as white table sugar, brown sugar, molasses, and confectioner’s sugar, as well as the high-fructose corn syrup added in processing, are also Simple Carbohydrates. These are pro- duced by refining and processing the carbohydrates from plants such as sugarcane, sugar beets, and corn. Monosaccharides The monosaccharide glucose, commonly referred to as blood sugar, is the most important carbohydrate fuel for the body. Glucose is produced in plants by the pro- cess of photosynthesis, which uses energy from the sun to combine carbon dioxide and water (Figure 4.4). Glucose rarely occurs as a monosaccharide in food. It is most often found as part of a disaccharide or starch. Two other common monosaccharides in the diet are fructose and galactose. Like glucose, each contains 6 carbon, 12 hydrogen, and 6 oxygen atoms, but they differ in their arrangement (Figure 4.5A). Fructose is a monosaccharide that tastes sweeter than glucose. It is found in fruits and vegetables and makes up more than half the sugar in honey. Because fructose does not cause as great a rise in blood glucose as other sugars, it is sometimes used in products for people with diabetes. However, because fructose causes an increase in blood lipids, its use should be limited. Fructose consumed in fruits or juices can also cause diarrhea in children. Most of the fructose monosaccharide A carbohydrate made up of a single sugar unit. disaccharide A carbohydrate made up of two sugar units. polysaccharide A carbohydrate made up of many sugar units.
eBook - PDFVisualizing Nutrition
Everyday Choices
- Mary B. Grosvenor, Lori A. Smolin(Authors)
- 2017(Publication Date)
- Wiley(Publisher)
Carbohydrates made up of only one sugar unit are called monosaccharides, those made up of two sugar units are called disaccharides, and those made up of more than two sugar units are called polysaccharides. Simple Carbohydrates Monosaccharides and disaccharides are classified as Simple Carbohydrates. The three most common monosaccharides in the diet are glucose, fructose, and galactose. Each contains 6 carbon, 12 hydrogen, and 6 oxygen atoms (C 6 H 12 O 6 ), but these three sugars differ in the arrangement of these atoms (Figure 4.4a). Glucose, the sugar referred to as blood sugar, is the most important carbohydrate fuel for the human body. The most common disaccharides in our diet are maltose, sucrose, and lactose (Figure 4.4b). polysaccharide A carbohydrate made up of many sugar units linked together. glucose A six-carbon monosaccharide that is the primary form of carbohydrate used to provide energy in the body. Calo Carbohydrate (g) ries Vitamin C (mg) Folate (μg) Calcium (mg) 0 50 100 150 200 250 Kiwi Red licorice FIGURE 4.3 Added versus naturally occurring sugars Choosing three kiwis rather than four pieces of red licorice is a more nutrient-dense choice. The kiwis are an unrefined source of sugar that also provides fiber and vitamin C, folate, and calcium. Most of the calories in the licorice are from added sugars; licorice is lower in nutrient density because it provides almost no other nutrients other than sugar. M. Price / Wiley 86 CHAPTER 4 Carbohydrates: Sugars, Starches, and Fibers Glycogen CH 2 OH C O OH C C C C H OH H H OH H OH Glucose H Starches Different types of starch consist of either straight chains or branched chains of glucose. We consume a mixture of starches in grain products, legumes, and other starchy vegetables. The polysaccharide glycogen is made of highly branched chains of glucose. This branched structure allows glycogen, which is found in muscle and liver, to be broken down quickly when the body needs glucose.
eBook - PDFNutritional Sciences
From Fundamentals to Food, Enhanced Edition
- Michelle McGuire, Kathy Beerman(Authors)
- 2017(Publication Date)
- Cengage Learning EMEA(Publisher)
In fact, a person with this disease must be vigilant when it comes to blood glucose control. What insights did you gain from Laura’s story about what it is like to have type 1 diabetes? What do you think your biggest challenges would be if you had this condition? 115 What Are Simple Carbohydrates? What Are Simple Carbohydrates? A carbohydrate is an organic compound made up of one or more sugar mol- ecules (Figure 4.1). Most people think of sugar as a substance used to sweeten their foods. Although this is true, sugars encompass far more than this. For example, cells use a special type of sugar, glucose, for an important source of energy. Carbohydrates are abundant in a wide variety of foods, and there are many different types. A carbohydrate consisting of a single sugar molecule is called a monosaccharide; a carbohydrate made of two sugar molecules is a disaccharide. Because of their small size, monosaccharides and disaccha- rides are called Simple Carbohydrates or simple sugars. MONOSACCHARIDES ARE SINGLE SUGAR MOLECULES Monosaccharides are single-sugar molecules that are made up of carbon, hydrogen, and oxygen atoms in the ratio of 1:2:1. For example, if a sugar has 6 carbon atoms, it also has 12 hydrogen and 6 oxygen atoms (written C 6 H 12 O 6 ). Because the number of carbon atoms and the arrangement of atoms can vary, monosaccharides typically have different shapes and sizes. There are hun- dreds of different naturally occurring monosaccharides, but the three most plentiful in food are glucose, fructose, and galactose. Although the structures of these sugars differ, they all have one thing in common: each contains six carbon atoms. Therefore these monosaccharides are referred to as hexose (hexa, meaning six) sugars. Although glucose, fructose, and galactose have the same molecular formula (C 6 H 12 O 6 ), each has a different arrangement of atoms (Figure 4.2).
eBook - PDF- Robert E.C. Wildman, Denis M. Medeiros(Authors)
- 2014(Publication Date)
- CRC Press(Publisher)
Not only were they composed of only carbon, hydrogen and oxygen, but also the ratio of carbon to water is typically one to one (C:H20). Thus, carbohydrate literally means carbon with water. Chemical carbohydrates are defined as polyhydroxyl aldehydes and ketones and their derivatives. Carbohydrates can vary from simpler 3- to 7-carbon single unit molecules to very complex branching polymers. While hundreds of different carbohydrates exist in nature, this text will take the simplest approach and group them into just a few broad categories: monosaccharides , disaccharides , oligosaccharides , and polysaccharides. Monosaccharides The monosaccharides that are relevant to human nutrition may be classified based on car bon number and include the trioses, tetroses, pentoses, and hexoses. Both aldoses (alde hydes) and ketoses (ketones) are present (Figure 4.1). Hexoses are the more common form of monosaccharides in the human diet. These include glucose , galactose , and fructose. Glu cose is found in some foods in a free form, especially ripened fruits and vegetables, while the majority of the glucose in the human diet is derived from the digestion of disaccharides and starch. Glucose is also the principal carbohydrate found in human circulation and is often referred to as blood sugar. Galactose is also found free in some foods, but to a relatively small degree. Most of the galactose in the human diet is derived from the digestion of the disaccharide lactose, which is found in milk and dairy foods. Fructose is found naturally in fruits and honey and is also derived from the disaccharide sucrose. Fructose is also pro vided in the human diet in the form of the popular food sweetening agent high-fructose com syrup (HFCS). Trioses such as glyceraldehyde and dihydroxyacetone are found as intermediary prod ucts of metabolic pathways (i.e., glycolysis). Tetroses include erythrose, threose, and eryth- rulose.
eBook - PDF- Marie Boyle(Author)
- 2022(Publication Date)
- Cengage Learning EMEA(Publisher)
Milk is the only animal-derived food that contains significant amounts of carbohydrate. Carbohydrates are divided into two categories: complex carbohydrates and Simple Carbohydrates. Com- plex carbohydrates include starch and fiber. Starches make up a large part of the world’s food supply, mostly as grains. For example, such staples as wheat, rice, and corn are rich sources of starch. Fiber is found abundantly in plants, especially in the outer portions of cereal grains, and in fruits, legumes, and most vegetables. Simple Carbohydrates include naturally occurring sugars in fresh fruits, in some vegetables, in milk and milk products, and as added sugars in concentrated form, such as in honey, corn syrup, or sugar in the sugar bowl. All of these carbohydrates have characteristics in common, but they are of dif- ferent merit nutritionally. 4.2 The Simple Carbohydrates: Monosaccharides and Disaccharides All carbohydrates are composed of single sugars—known as monosaccharides — alone or in various combinations, and all carbohydrates but fiber can be converted to glucose in the body. Green plants make glucose from carbon dioxide and water through a process known as photosynthesis in the presence of chlorophyll and sun- light, as illustrated in Figure 4-2. Glucose is not a very sweet sugar, but plants can rearrange its atoms to form another sugar, fructose, which is sweet to the taste. Fructose is found mostly in fruits, in honey, and as part of another sugar—table sugar. Glucose and fructose are the most common monosaccharides in nature. Some sugars are double sugars—known as disaccharides—made by bonding two monosaccharides together. When glucose and fructose are bonded together, they form sucrose, or table sugar, the product most people refer to when they use the term sugar. The sweet taste of sucrose comes primarily from the fructose in its structure.
- Frederick Bettelheim, William Brown, Mary Campbell, Shawn Farrell(Authors)
- 2019(Publication Date)
- Cengage Learning EMEA(Publisher)
525 CONTENTS 19.1 Monosaccharides: The Simplest Carbohydrates 19.2 Cyclic Structures of Monosaccharides 19.3 Characteristic Reactions of Monosaccharides 19.4 Disaccharides and Oligosaccharides 19.5 Polysaccharides 19.6 Acidic Polysaccharides Carbohydrates 19 19.1 Monosaccharides: The Simplest Carbohydrates Carbohydrates are the most abundant organic compounds in the plant world. They provide chemical energy (glucose, starch, glycogen); are com-ponents of supportive structures in plants (cellulose), crustacean shells (chitin), and connective tissues in animals (acidic polysaccharides); and are essential components of nucleic acids ( D -ribose and 2-deoxy-D -ribose). Carbohydrates account for approximately three-fourths of the dry weight of plants. Animals (including humans) get their carbohydrates by eating plants, but they do not store much of what they consume. In fact, less than 1% of the body weight of animals is made up of carbohydrates. Carbohydrate means “hydrate of carbon” and derives from the formula C n s H 2 O d m , such as: ● Glucose (blood sugar): C 6 H 12 O 6 , which can be written as C 6 s H 2 O d 6 ● Sucrose (table sugar): C 12 H 22 O 11 , which can be written as C 12 s H 2 O d 11 Not all carbohydrates have this general formula, but the term carbohydrate has become so firmly rooted in the chemical nomenclature that, although not completely accurate, it persists as the name for this class of compounds. At the molecular level, most carbohydrates are polyhydroxyalde-hydes, polyhydroxyketones, or compounds that yield them after hydrolysis. The simpler members of the carbohydrate family are often referred to as saccharides because of their sweet taste (Latin: saccharum, “sugar”). Car-bohydrates are classified as monosaccharides, oligosaccharides, or polysac-charides depending on the number of simple sugars they contain. Carbohydrates Polyhydroxyaldehydes or polyhydroxyketones, or substances that give these compounds on hydrolysis Charles D.
No longer available |Learn more- Linda DeBruyne, Kathryn Pinna(Authors)
- 2019(Publication Date)
- Cengage Learning EMEA(Publisher)
Chemists describe the sugars as: ● Monosaccharides (single sugars) ● Disaccharides (double sugars) Starch and fiber are:* ● Polysaccharides —chains of monosaccharide units All of these carbohydrates are composed of the single sugar glucose and other com-pounds that are much like glucose in composition and structure. Figure 3-1 shows the chemical structure of glucose. Monosaccharides Three monosaccharides are important in nutrition: glucose, fructose , and galactose . All three monosaccharides have the same number and kinds of atoms but in different arrangements. Glucose Most cells depend on glucose for their fuel to some extent, and the cells of the brain and the rest of the nervous system depend almost exclusively on glucose for their energy. The body can obtain this glucose from carbohydrates. To function optimally, the body must maintain blood glucose within limits that allow the cells to nourish themselves. A later section describes blood glucose regulation. Fructose Fructose is the sweetest of the sugars. Fructose occurs naturally in fruit, in honey, and as part of table sugar. However, most fructose is consumed in sweet beverages such as soft drinks, in ready-to-eat cereals, and in other products sweetened with high-fructose corn syrup or other added sugars . Glucose and fructose are the most common monosaccharides in nature. carbohydrates: energy nutrients composed of monosaccharides. carbo 5 carbon hydrate 5 water monosaccharides (mon-oh-SACK- uh-rides) : single sugar units. mono 5 one saccharide 5 sugar *Monosaccharides and disaccharides (sugars) are sometimes called Simple Carbohydrates , and the polysaccha-rides (starch and fiber) are sometimes called complex carbohydrates . Grains, vegetables, legumes, fruit, and milk offer ample carbohydrate. Polara Studios, Inc. Photo 3-1 disaccharides (dye-SACK-uh-rides) : pairs of sugar units bonded together. di 5 two polysaccharides: long chains of monosaccharide units arranged as starch, glycogen, or fiber.
eBook - PDF- Marie Dunford, J. Doyle, Marie Dunford(Authors)
- 2021(Publication Date)
- Cengage Learning EMEA(Publisher)
Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it. 104 Chapter 04 Carbohydrates and athletes can choose from a variety of liquid, solid, or semisolid products containing the proper amount and type of carbohydrates. Carbohydrate-containing foods also taste sweet, making them a palatable energy source. 4.1 Carbohydrates in Food LO 4.1 Classify carbohydrates according to their chemical composition. Carbohydrates are found in various forms in food. To understand the differences in these various forms, one must look more closely at their chemical composi- tion. Carbohydrates are generally classified as mono- saccharides, disaccharides, or polysaccharides. It helps to know that saccharide means sugar, mono means one, di means two, and poly means many. Therefore, a monosaccharide consists of one sugar molecule, a disaccharide two sugar molecules, and a polysaccharide many sugar molecules. Sugar alcohols are derived from mono- and disaccharides and are dis- cussed separately (see Spotlight on. . .Sugar Alcohols). The three monosaccharides found in foods are glucose, fructose, and galactose. Their characteris- tics are outlined in Table 4.1, and their structures are shown in Figure 4.2. In which foods are these monosaccharides found? Although glucose can be found by itself in foods, most of the time, it is a component of food disaccharides and polysaccharides. Fructose is naturally found in fruits and vegetables, but the largest amount of fructose in American diets is added to foods when they are processed, such as the addition of high-fructose corn syrup as a sweetener. Galactose is a monosaccharide, but it is found naturally in food only as part of the disaccharide, lactose.
eBook - PDF- Mary B. Grosvenor, Diana Bedoya(Authors)
- 2014(Publication Date)
- Wiley(Publisher)
The three most common mono- saccharides in our diet are glucose, fructose, and galac- tose. Each contains six carbon, 12 hydrogen, and six oxygen atoms (C 6 H 12 O 6 ), but these three sugars differ in the arrangement of these atoms (Figure 4.4a). Glucose, of- ten called blood sugar, is the most important carbohydrate fuel for the human body. Under normal conditions, the brain and red blood cells rely solely on glucose to fuel their activity. The most common disaccharides in our diet are maltose, sucrose, and lactose (Figure 4.4b). glucose A six-car- bon monosaccharide that is the primary form of carbohydrate used to provide en- ergy in the body. Complex Carbohydrates Complex carbohydrates are polysaccharides; they are gen- erally not sweet-tasting the way sim- ple carbohydrates are. They include glycogen in animals and starches and fibres in plants (Figure 4.4c). Glycogen is the storage form of glu- cose in humans and other animals. It is found in the liver and muscles, but we don’t consume it in our diet because the glycogen in animal muscles is broken down soon after the animal is slaughtered. Starch is made up of glu- cose molecules linked together glycogen The stor- age form of carbohy- drate in animals, made up of many glucose molecules linked together in a highly branched structure. starch A carbohy- drate found in plants, made up of many glucose molecules linked in straight or branched chains. THE PLANNER ✓ ✓ b. Beans contain soluble fibre and small polysaccharides that cannot be broken down by human digestive enzymes. Both of these pass into the large intestine, where their digestion by bacteria creates gas. Over-the-counter enzyme tablets and solutions (such as Beano®) can be taken to digest the small polysaccharides and thus reduce the amount of gas produced. a. Jams and jellies are thickened with pectin, which is a soluble fibre found in fruits and vegetables. Some foods are thickened with gums, which combine with water to keep solutions from separating.
No longer available |Learn more- Linda DeBruyne, Kathryn Pinna(Authors)
- 2016(Publication Date)
- Cengage Learning EMEA(Publisher)
Chemists describe the sugars as: • Monosaccharides (single sugars) • Disaccharides (double sugars) Starch and fiber are:* • Polysaccharides—compounds composed of chains of monosaccharide units All of these carbohydrates are composed of the single sugar glucose and other com- pounds that are much like glucose in composition and structure. Figure 3-1 shows the chemical structure of glucose. Monosaccharides Three monosaccharides are important in nutrition: glucose, fructose, and galactose. All three monosaccharides have the same number and kinds of atoms but in different arrangements. Glucose Most cells depend on glucose for their fuel to some extent, and the cells of the brain and the rest of the nervous system depend almost exclusively on glucose for their energy. The body can obtain this glucose from carbohydrates. To function optimally, the body must maintain blood glucose within limits that allow the cells to nourish themselves. A later section describes blood glucose regulation. Fructose Fructose is the sweetest of the sugars. Fructose occurs naturally in fruits, in honey, and as part of table sugar. However, most fructose is consumed in sweet beverages such as soft drinks, in ready-to-eat cereals, and in other products sweetened with high-fructose corn syrup or other added sugars. Glucose and fructose are the most common monosaccharides in nature. Galactose The third single sugar, galactose, occurs mostly as part of lactose, a disaccharide also known as milk sugar. During digestion, galactose is freed as a single sugar. carbohydrates: energy nutrients composed of monosaccharides. carbo 5 carbon hydrate 5 water monosaccharides (mon-oh-SACK- uh-rides): single sugar units. mono 5 one saccharide 5 sugar disaccharides (dye-SACK-uh- rides): pairs of sugar units bonded together. di 5 two *Monosaccharides and disaccharides (sugars) are sometimes called Simple Carbohydrates, and the polysaccharides (starch and fiber) are sometimes called complex carbohydrates.
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