CARBOHYDRATEs presentation notes .pptx

carbohdrate

1. CARBOHYDRATES. Chengula

2. 1.2 FOOD NUTRIENTS AND THEIR PHYSIOLOGICAL IMPORTANCES

3. CARBOHYDRATES CHEMISTRY Carbohydrate is an organic compound made up by elements Carbon; Oxygen and Hydrogen. Oxygen and Hydrogen are present in the same proportion as for water (H 2 O) hence the term hydrate. Simple formula C n (H 2 O) n

4. CARBOHYDRATES CLASSIFICATION OF CARBOHYDRATES Carbohydrates are of three major classes, namely: Polysaccharides Disaccharides Monosaccharides Monosaccharides and disaccharides are reffered as simple sugars/ simple carbohydrates where as polysaccharides are termed as complex carbohydrates.

5. CARBOHYDRATES MONOSACCHARIDES.  These are the fundamental units of all other carbohydrates They are the building blocks of all carbohydrates General formula– C n H 2n O n They are the end product of carbohydrate digestion.

6. CARBOHYDRATES Types of monosaccharides Glucose Fructose Galactose They have the same number and kinds of atoms , but in different arrangements (isomers) The difference in chemical arrangements accounts for their difference in chemical properties. Generally monosaccharides are sweet and soluble in water

7. CARBOHYDRATES CLASSIFICATION GLUCOSE The chemical composition of glucose is C 6 H 12 O 6 Also known as Blood sugar Glucose is found as a constituent in almost all other complex carbohydrates e.g. disaccharides, polysaccharides i.e starch, glycogen.

8. GLUCOSE FOOD SOURCE OF CLUCOSE Ripe fruits, certain vegetables such as Onions, beet roots, commercially produced glucose, liquid or tablet glucose

9. FRUCTOSE Fructose The chemical composition of fructose is C 6 H 12 O 6 It is also known as fruit sugar . It is the sweetest among all other monosaccharides

10. FRUCTOSE Food source of fructose Mainly occur in fruits and honey It is also added as additive as sweeternous agent e.g. high fructose corn syrup etc.

11. GALACTOSE Galactose The chemical composition of galactose is C 6 H 12 O 6 It rarely occurs free in nature.

12. GALACTOSE Food sources for Galactose Mainly found in milk of mammal as part of lactose (Milk sugar)

13. DISSACCHARIDES These are also reffered as double sugars . They are made up of two monosaccharides units joined together Glucose occurs in all disaccharides while other member can be either Fructose or Galactose .

14. DISSACCHARIDES General Properties Soluble in water Sweet

15. DISSACCHARIDES Types of Disaccharides Sucrose Lactose Maltose

16. DISACCHARIDES Sucrose It is a combination of Glucose and Fructose Glucose + Fructose =Sucrose This is also known as Table sugar. Sucrose is the most familiar sugar that is used mostly in cookery.

17. DISACCHARIDES Food sources for sucrose Sugarcane, beetroots and some vegetables, fruits and grains. Table sugar -Is a refinery product of sugarcane and beetroots

18. DISACCHARIDES Lactose It is a product of Glucose and Galactose. Glucose + Galactose = Lactose (Milk sugar) It is also known as milk sugar

19. DISACCHARIDES Food sources for Lactose It is found in the milk of mammals

20. DISACCHARIDES Maltose Product of two molecules of glucose. Glucose + Glucose = Maltose It is also known as Malt sugar (germinated and dried grains)

21. DISACCHARIDES Food sources for Maltose Cereals i.e. maize, wheat, barley etc.  

22. DISACCHARIDES NOTE During digestion, all disaccharides are broken down to monosaccharides before being absorbed into the blood stream

23. POLYSACCHARIDES These are polymers of monosacharides . They consists of many units of monosaccharides joined together

24. POLYSACCHARIDES Common polysaccharides. There are five common polysaccharides, namely; Starch Cellulose Glycogen

25. POLYSACCHARIDES Starch This is a polymer of glucose  Consists of many units of glucose joined together

26. POLYSACCHARIDES Food sources for starch Starch is formed during photosynthesis in plants and it is found in plants food reserve; roots, tubers, cereals, pulses, vegetables, grains etc. Starch is the main source of carbohydrate in the body  

27. POLYSACCHARIDES Cellulose It is a very complex polymer of glucose It can not be digested by man. However it forms a great value to body as dietary fibre .

28. POLYSACCHARIDES Glycogen. Form of polysaccharides found in animal tissues only. It is not found in plants at all. Highly stored in the liver and considerably amount in muscle tissue. It is easily hydrolysed. It is a source of energy reserve, hence used as a source of energy when glucose is not highly available.

29. Carbohydrates Physiological role of carbohydrates.  Chief source of energy especially in brain and nerve cells. Build fat stores Cell component (Build cells)- glycoprotein

30. CARBOHYDRATES REQUIREMENTS The carbohydrates requirements depends on the energy requirements  

31. ENERGY REQUIREMENTS Calories The energy value of food is expressed in terms of a unit of heat, the kilocalorie However the accepted international unit for energy is joule (J) 1kCal = 4.2 kJ

32. ENERGY REQUIREMENTS Energy requirements also depends on the energy expenditure hence varies from individual to individual  

33. ENERGY EXPENDITURE Components of Total Energy Expenditure(TEE) Basal metabolism Physical activity Thermic effect of food

34. COMPONENTS ENERGY EXPENDITURE Basal Metabolism The amount of energy required to maintain life sustaining activities (breathing, circulation, heartbeat, secretion of hormones) for a specific period of time Constitutes the largest proportion of TEE (70%) It is measured by BMR

35. Basal Metabolic Rate (BMR) Is the rate at which the body spends energy to keep all these life supporting processes going Is the rate at which the body uses energy for the chemical processes that keep us alive and warm and that build tissues and secrete fluids

36. Factors affecting BMR Age Sex Body size Body composition Thyroid function

37. Other Factors affecting BMR Fasting/ starvation stress Menstruation Body temperature

38. Physical activity This is the amount of energy which the body spend on various activities It the second largest proportion of the TEE It demands about 20% to 30% of our TEE Can altered

39. Factors affecting energy for physical activity Body size Intensity of the activity Duration of the activity

40. Thermic Effect of Food/Diet induced thermogenesis This is the energy which our body spend for digestion, absorption, metabolism, and food storage Eating cause an increase in cellular activity It account for approximately 7% to 10% of the TEE Affected by the type of food such that protein food have high TEF than others

41. Adaptive Thermogenesis This is the energy spend by the body to adjust to changing physical and biological environmental situations Energy used to adopt to change in weather Physiological changes such as illness; pregnancy; lactation etc

42. Total energy expenditure

43. Factors affecting energy expenditure?????

44. CARBOHYDRATES REQUIREMENTS Calorific value of Carbohydrate 1gram of carbohydrate = 4 kcal.

45. RECOMMENDED DAILY INTAKES FOR ENERGY Individual groups Kcals/day KJ/day Children 0-1 year 1-2 years 2-3 years 3-5 years 5-7 years 7-9 years 800 1200 1400 1600 1800 2100 3360 5040 5880 6720 7560 88020 Adolesencents Boys Girls 2800 2300 11,760 9,660

46. RECOMMENDED DAILY INTAKES FOR ENERGY Individual groups Kcals /day K /day Adults: Men 18 – 35 years Sedentary Active 2700 11340 Moderately Active 3000 12600 Very Active 3600 15120 35-65 years Sedentary Active 2600 10920 Moderately Active 2900 12180 Very Active 3600 15120

47. RECOMMENDED DAILY INTAKES FOR ENERGY Individual groups Kcal/day KJ/day Women: 18 – 35 years Sedentary Active 1900 7980 Moderately Active 2200 9240 Very Active 2500 10500

48. RECOMMENDED DAILY INTAKES FOR ENERGY Individual groups Kcal/day KJ/day 35- 65 years: Most occupations 2050 8610 Both Men and Women 75 + years 2000 8400 Women: Pregnant 2400 10080 lactating 2700 11340