1 Carbohydrates Contain the Elements:Carbon Hydrogen Oxygen They Are Split Into Four Groups Known As: Monosaccharides(Monomers) Disaccharides(Dimers)(2) Oligosaccharides(2-10) Polsaccharides(Polymers)(<10)

2 Carbohydrates Many carbohydrates are soluble in water.The usual chemical test for the simpler carbohydrates is heating with Benedicts solution. The formula for a carbohydrate is (CH2O)n The n represents the number of times the CH2O unite is repeated.

3 Monosaccharides (monos)The Most Important Monosaccharide Is Glucose. A Monosaccharide is made up of 1 sugar unit. Monos are reducing sugars. Fructose and Galactose are all so Monosaccharides, They all have the same chemical formula but different structures.

4 The Structural Differences between Glucose, Galactose, and Fructose

5 Three nutritionally important monosaccharidesGlucose Fructose Galactose

6 Glucose Blood glucose and blood sugar in the body Most abundant monosaccharide in the body Is the preferred and main source of energy for the brain and red blood cells Part of every disaccharide Only monosaccharide in starches

7 Fructose Sweetest of natural sugars Found abundantly in fruits Part of high-fructose corn syrup Galactose Commonly occurs as part of dissaccharide lactose

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9 Disaccharides Three Disaccharides Sucrose Most common Lactose MaltoseLeast common Formed from digestion of starches

10 Monosaccharides Link to Form Disaccharides

11 Glycosidic Bond This is when two monosaccharides join to form a Disaccharide. The reaction is similar to condensation. The reaction involves the water been given off.

12 Glycosidic Bond Above is the structures of a Glycosidic bond.It forms a Disaccharide

13 Hydrolysis This is the breaking down of a glycosidic bond.Instead of water been taken away water is added. Lysis means splitting.

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23 Polysaccharides Starch Plants store glucose in chains of starchAmylose Straight chain More resistant to digestion Resistant starch May improve heStarcalth of digestive tract May improve glucose tolerance May stimulate growth of beneficial intestinal bacteria Amylopectin Branched chains Easier to digest

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25 Polysaccharides Fiber Nondigestible polysaccharides Provides no energyClassification Soluble Pectins, beta-glucan, some gums, mucilage Easily fermented by intestinal bacteria Carbon dioxide, methane, some fatty acids Insoluble Cellulose, lignin, some hemicelluloses Not easily fermented

26 Fiber Health Benefits Soluble fibersSlow gastric emptying and may delay absorption of some nutrients Helps reduce serum cholesterol Improve appetite control Normalize blood glucose levels May help protect against colon cancer Insoluble fibers Relieves constipation Most plant foods contain both soluble and insoluble fibers

27 ↓ BG → glycogen breakdown → ↑ BGPolysaccharides Glycogen Storage form of glucose in animals Long, branched chains of glucose Stored in liver and muscle Liver glycogen response to blood glucose (BG) levels ↓ BG → glycogen breakdown → ↑ BG Muscle glycogen can be broken down for energy for the muscle

28 The Comparison of Starch and Glycogen Molecules

29 Oligosaccharides Similar in length to simple carbohydratesSimilar in makeup to polysaccharides Humans lack the enzymes necessary to digest them Intestinal microflora digest and ferment them Cause bloating, discomfort, and flatulence Food sources Legumes, beans, cabbage, brussels sprouts, broccoli

30 Carbohydrates Carbohydrates can also be classified as Reducing Sugars1. Possess a free aldehyde(-CHO) or ketone (-C=0) Group. 2. Can reduce the Cu2+ cupric ions (blue)in Fehling’s or Benedict’s Solution to Cu+ cuprous ions (reddish) that precipitate out as Cu2O(cuprous oxide). 3. Maltose. lactose, melibiose, gentiobiose, cellobiose, mannotriose.. Non-reducing 1. A free aldehyde or ketonic group is lacking. 2. No such reaction. 3. Sucrose, trehalose,raffinose, gentiarose, melezitose. n reducing Sugars

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32 Benedict test Benedict test videoBenedict's Test for non-reducing Sugars is a test which determines the presence of non-reducing sugars in a test solution. Benedict test video

33 Benedict test

34 Iodine Test The Iodine test is used to test for the presence of starch. Iodine solution — iodine dissolved in an aqueous solution of potassium iodide — reacts with the starch, producing a purple-black colour Iodine test video

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37 Carbohydrates can also be separated into groups based on the Glycemic Index, which measures how high and how quickly blood glucose levels change after eating carbohydrates. The higher the Glycemic Index, the higher the rise in blood sugar and the longer it takes to return to normal. For a healthy diet, it is best to focus on foods with a low Glycemic Index (e.g., whole grains, oats, and whole wheat pasta). Foods with a high Glycemic Index have been linked to elevated risks of heart disease and diabetes. A low-GI food will release glucose more slowly and steadily, which leads to more suitable postprandial (after meal) blood glucose readings. A high-GI food causes a more rapid rise in blood glucose levels and is suitable for energy recovery after exercise or for a person experiencing hypoglycemia.

38 Glycemic Index Classifies the effects of carbohydrate-containing foods on blood glucose May be helpful for diabetics Glycemic index (GI) refers to the measured upward rise, peaks, and falls of blood glucose following consumption of high-carbohydrate food Ranks foods according blood glucose

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40 Glycemic Load Glycemic load (GL) of food is a number that estimates how much the food will raise a person's blood glucose level after eating it. One unit of glycemic load approximates the effect of consuming one gram of glucose. Glycemic load (GL) – adjust GI by taking into account the amount of carbohydrate consumed in a typical serving of food Factors affecting GI Ripeness of fruit Cooking Processing Size of food pieces Amount of fiber Combinations of food eaten

41 Glycemic Index and Glycemic LoadUsefulness of GI and GL for disease prevention and weight management is controversial Is helpful in educating people about Carbohydrate content of foods Portion sizes Serving numbers

42 Carbohydrate Digestion and AbsorptionDisaccharides and starches are digested to monosaccharides Monosaccharides are easily absorbed Fiber passes through the GI tract undigested

43 Lactose Intolerance Deficiency of lactase, the enzyme that digest lactose Maldigestion – inability to digest lactose due to low levels of the enzyme Intolerance Maldigestion resulting in nausea, cramps, bloating, flatulence, and diarrhea

44 Absorption of CarbohydratesOnce digested to monosaccharides Absorbed through the intestinal cell mucosa Transported to the liver via the portal vein Metabolic needs direct fate of the monosaccharides Galactose and fructose Used by the liver for energy Converted to glucose Glucose Used for energy Converted to glycogen through glycogenesis Converted to glycerol and fatty acids for storage in addipocytes

45 Functions of CarbohydrateProvide energy 4 kilocalories per gram Maintain blood glucose Carbohydrate intake Glycogenolysis > 4 hours after a meal Spare protein Prevents the need for glyconogenesis Prevents ketosis

46 How to Maintain Blood Glucose LevelsGoal for blood glucose is 70–100 mg/dl Insulin – lowers blood glucose levels Needed for glucose to enter the cell from the blood stream Exception: liver, kidney, and brain cells Helps convert glucose to glycogen through glycogenesis Helps convert glucose to fatty acids through lipogenesis Inhibits lipolysis Glucagon – increases blood glucose levels Stimulates the release of glucose into the blood Stimulates glycogenolysis Stimulates gluconeogensis

47 Insulin and Glucagon Regulate Glucose Metabolism

48 Dietary Fiber Benefits Helps lower risk of Bowel irregularity ObesityHeart disease Cancer Diabetes mellitus

49 Quick Review Glycemic index (GI) ranks foods according to effects on glucose levels compared to white bread or pure glucose Glycemic load adjust for serving size Foods that contain high fiber or are eaten with protein and fat generally have a lower GI. High-fiber diet health benefits include reduced risk of Constipation Diverticulosis Heart disease Obesity Diabetes Mellitus Cancer

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51 Food Sources of Carbohydrates

52 Quick Review Fresh fruits and vegetables Whole grainsExcellent sources of fiber are Fruits Vegetables Packaged foods can be good sources of starch and fiber Read label carefully Avoid too much sugar, fat, and kilocalories

53 Natural versus Added SugarNaturally occurring sugar Sugars such as fructose and lactose found naturally in foods Tend to be nutrient dense Added sugar Sugars added to processed foods and sweets Empty calories

54 Slices of an Orange versus Orange Slices

55 Added Sugar Reasons sugar is added to foods To keep product moistTo turn pastries a golden brown Preservative Thickening agent Make yeast rise Make foods taste sweet

56 Finding Added Sugars on the Label

57 Health Effects of SugarSugar can contribute to Dental carries Elevated level of fat in the blood Lowing of HDL cholesterol Sugar does not cause Increased risk of diabetes Hyperactivity in children Sugar is not considered an addictive substance

58 How many carbohydrates do I need in my diet?Carbohydrates should account for 45% - 65% of the calories in your diet, which is roughly 225 g – 325 g of carbohydrates for someone on a 2000-calories diet.

59 Putting It All TogetherCarbohydrates are an important part of a healthy diet Whole grains, fruits, vegetables, and lean dairy products Provide carbohydrates and vitamins and minerals Should be the predominant source of carbohydrates Whole grains, fruits, and vegetables are a good source of fiber and phytochemicals Adequate amounts of these can prevent many chronic disease Sugary foods should be eaten in moderation