The Carbohydrates: Sugars, Starches, and FibersClass overviewClass ObjectivesCarbohydrate Review4 main types of atoms in nutrientsAtoms and Their BondsAtoms and Their Bonds*Structure of CarbohydratesDietary Carbohydrate FamilyDietary CarbohydratesCarbohydrate FamilyGlucose (“blood sugar”)Fructose (“fruit sugar)GalactoseThe Monosaccharides*Slide 16MaltoseSucroseLactoseSlide 20GlycogenStarchesPowerPoint PresentationDietary FiberSlide 25The Carbohydrates: The Carbohydrates: Sugars, Starches, Sugars, Starches, and Fibersand FibersChapter 4 (Lecture #1)Chapter 4 (Lecture #1)Dr. Alisha RovnerDr. Alisha RovnerUniversity of DelawareUniversity of DelawareNutrition Concepts (NTDT200)Nutrition Concepts (NTDT200)Fall 2013Fall 2013Class overviewClass overview•Carbohydrate review•Chemistry review•Carbohydrate structureClass ObjectivesClass Objectives•Explain what a carbohydrate is and what food sources of carbohydrates are•Understand the chemical structure of carbohydrates•Identify the monosaccharides, disaccharides, and polysaccharides common in nutrition and their major food sourcesCarbohydrate ReviewCarbohydrate Review•Macronutrient that provides 4 kcal/g•All plant foods (whole grains, vegetables, legumes, fruits) provide ample carbohydrates•Acceptable Macronutrient Distribution Range (AMDR) for adults•Carbohydrates ≈ 45 – 65% of kcal •Fat ≈ 20 - 35 % of kcal•Proteins ≈ 10 - 35 % of kcal4 main types of atoms in nutrients4 main types of atoms in nutrients•Carbon (C)•Nitrogen (N)•Oxygen (O)•Hydrogen (H)Atoms and Their BondsAtoms and Their Bonds•Each atom can form a certain number of chemical bonds with other atoms•Carbon atoms- 4•Nitrogen atoms- 3•Oxygen atoms- 2•Hydrogen atoms- 1Atoms and Their Bonds*Atoms and Their Bonds**Bonds are represented as lines between the chemical symbolsStructure of Carbohydrates Structure of Carbohydrates •Composed of carbon, hydrogen, and oxygen•Arranged as monosaccharides (single sugars) or multiple disaccharides•Most carbohydrates have a ratio of one carbon molecule to one water molecule* carbo= carbon (C) hydrate= with water (H2O)Dietary Carbohydrate FamilyDietary Carbohydrate Family•Monosaccharides•Most basic units of carbohydrates•All have same # and kinds of atoms but in different arrangements•Disaccharides•Pairs of monosaccharides linked together •Polysaccharides•Contain many glucose units and in some cases monosaccharides strung togetherDietary CarbohydratesDietary Carbohydrates•Monosaccharides and disaccharides (sugars) are sometimes called simple carbohydrates•Polysaccharides (starches and fibers) are sometimes called complex carbohydratesCarbohydrate FamilyCarbohydrate Family•Monosaccharides- single sugars•Glucose (aka. blood sugar) • Fructose (aka. fruit sugar) - Sweetest of sugars• Galactose - Found in very few foodsGlucose (Glucose (““blood sugarblood sugar””))•Serves as an essential energy source for all the body’s activities•People don’t eat glucose directly. •When carbohydrate rich foods are eaten the body receives glucose for immediate energy and converts some into glycogen for reserve energy.Fructose (Fructose (““fruit sugar)fruit sugar)•Sweetest of the sugar•Occurs naturally in fruits and honey•Soft drinks, ready to eat cereals and desserts have been sweetened with high fructose corn syrup.GalactoseGalactose•Occurs naturally in only a few foods•Found in milk•Galactosemia is a rare genetic disorder in which the body is unable to metabolize galactose. Treatment requires the strict exclusion of lactose/galactose from the diet.The Monosaccharides** All have same # and kinds of atoms but in different arrangementsCarbohydrate FamilyCarbohydrate Family•Disaccharides*- sugars composed of pairs of monosaccharides. Maltose (glucose + glucose) Sucrose (glucose + fructose) Lactose (glucose + galactose)* All contain glucoseMaltoseMaltose•Two glucose units•Produced whenever starch breaks down•Occurs during the fermentation process that yields alcohol•Only in a few foods including barleySucroseSucrose•Fructose + glucose•Commonly known as table sugar•Also occurs in many fruits and some vegetables and grainsLactoseLactose•Galactose + glucose•Principal carbohydrate of milk•Known as milk sugarCarbohydrate FamilyCarbohydrate Family•Polysaccharides •More complex than monosaccharides and disaccharides•Contain many glucose units•Three types important in nutrition•Glycogen•Starches•FibersGlycogenGlycogen•Animal polysaccharide composed of glucose•When people eat carbohydrate rich foods their bodies receive glucose for immediate energy and convert some glucose into glycogen for reserve energy.StarchesStarches•Humans store glucose as glycogen and plant cells store glucose as starches•Long, branched or unbranched chains of hundreds or thousands of glucose molecules linked together •When a person eats plants the body hydrolyzes starch into glucose for energyFigure 4-6b p99Dietary FiberDietary Fiber•Structural parts of plants, found in all plant derived foods•2 types of fiber:•Soluble- found in oats, barley legumes. Associated with lowering blood cholesterol and glucose.•Insoluble -found in whole grains. Promotes bowel movements and alleviates constipation.Table 4-1
View Full Document