Its all about carbohydrates. Carbohydrates, or carbs, are sugar molecules. Along with proteins and fats, carbohydrates are one of three main nutrients found in foods and drinks. Your body breaks down carbohydrates into glucose. Glucose, or blood sugar, is the main source of energy for your body's cells, tissues, and organs.

1. LectureV
Aqsa Akhtar
School of Food and Agricultural Sciences
University of Management andTechnology
FST-2101 3(3-0)
Food Chemistry
1

2. Lecture 5
Carbohydrates-1

3. Session 5: Learning Outcomes
Course Learning Objective
▪Differentiate between major and minor food components and their
functions and physiochemical properties
Session Learning Objective
▪Explain properties and reactions of carbohydrates, lipids, proteins,
enzymes during storage and processing of food
Session learning Outcomes
❖SLO 5.1: Understand the basics of carbohydrates and classes of
carbohydrates
❖SLO 5.2: Describe the physical and chemical characteristics of
monosaccharides
❖SLO 5.3: Elaborate the different types of monosaccharides and their
role in nutrition

4. Carbohydrates
▪Hydrates of carbon, containing C, H and O
▪Widely available, and inexpensive
▪Polyhydroxylated compounds having at least 3 carbon atoms and a
potentially active carbonyl group which may be an aldose or a ketose
group
▪Simply called saccharides (aka sugars) with molecular formula (CH2O)n
▪Carbohydrates comprise of > 90% of the dry matter of plants

5. Types of Carbohydrates

6. Carbohydrates (Cont)
▪Present in different molecular structures, sizes, and shapes
▪Exhibit a variety of chemical and physical properties
▪Along with glucose and fructose, they are human energy sources,
providing 70 – 80% of the calories in the human diet worldwide

7. Carbohydrate Synthesis in Plants

8. Types of Carbohydrates
Simple Carbohydrates
▪ Monosaccharides
• Glucose
• Fructose
• Galactose
▪ Disaccharides
• Sucrose
• Maltose
• Lactose
Complex Carbohydrates
▪ Oligosaccharides
• Maltodextrins
• Raffinose
• Stachyose
▪ Polysaccharides
• Glycogen (Animals)
• Starches (Plants)
• Fibers (Plants)

9. Carbohydrates in Human Body

10. Classification of Carbohydrates

11. Classification of Carbohydrates

13. Functional Groups
▪Monosaccharides contain several functional groups. They contain the
hydroxyl group represented as –OH. They also contain a carbonyl
group, which is an oxygen double bonded to a carbon atom
▪The carbonyl group may be an aldehyde or a ketone
A carbonyl group is a functional
group composed of a carbon atom double-
bonded to an oxygen atom: C=O

14. 1. Monosaccharides
▪Monosaccharides cannot be hydrolyzed and referred to as
simple sugars
▪Monomeric units joined together to form larger structures, are
called oligosaccharides and polysaccharides, and can be
converted into their constituent monosaccharides by hydrolysis
▪Classified on the basis of the nature of carbonyl group
▪Monosaccharides that contain a carbonyl group have the suffix
“ose”
▪Polyhydroxy aldehydes are called aldoses (Glucose)
Polyhydroxy ketones are called ketoses (Fructose)

15. Carbohydrates: Condensation
1. Monosaccharides (Cont)
Carbohydrates: Hydrolysis

16. 1. Monosaccharides (Cont)

17. 1. Monosaccharides (Cont)
▪ Monosaccharides that contain aldehyde group are referred as aldose
▪ Monosaccharides that contain ketone group are referred as ketose

18. 1. Monosaccharides (Cont)

19. 1. Monosaccharides (Cont)
▪Solids at room temperature
▪Extremely soluble in water
▪ Carbohydrates are hydrophilic substances which are
soluble in water and alcohol
▪ The (OH) groups of carbohydrates are primarily
responsible for their solubility in water

20. 1. Monosaccharides: Simple Sugars
Glucose
▪Found in fruits, vegetables, honey
▪Most abundant monosaccharide found in nature
▪Carbohydrate form used by the body, referred to
as “blood sugar”
▪Glucose also known as dextrose and grape sugar
▪Basic sub-unit of other larger carbohydrate
molecules
▪Excess in the blood is called hyperglycemia and
presence in urine (glucosuria) indicates diabetes
mellitus

21. 1. Monosaccharides: Simple Sugars
Fructose
▪Latin word for fruit — "fructus“
▪Sweetest of the sugars
▪Occurs naturally in fruits & honey, also called
“fruit sugar” or levulose
▪Combines with glucose to form sucrose
▪Released by the hydrolysis of inulin
▪Can be converted to glucose in the liver

22. 1. Monosaccharides: Simple Sugars
Galactose
▪Greek word for milk-"galact“
▪Found as a component of lactose in milk
▪Synthesized in the lactating mammary gland
▪Constituent of glycolipids and glycoproteins
▪Can be converted to glucose in the liver
▪Accumulation can lead to galactosemia and
cataract (galactitol)

23. Key Concepts: Summary
✓Macronutrients essential to living organisms and energy source for the
human body
✓Organic molecules in which carbon (C) bonds with hydrogen and oxygen
(H2O) in different ratios depending on the specific carbohydrate
✓Plants harvest energy from the sun and manufacture carbohydrates during
photosynthesis
✓In a reverse process, animals break down carbohydrates during
metabolism to release energy
✓All carbohydrates are made up of units of sugar

24. Key Concepts: Summary

25. Take Home Activity
Bring some examples of aldoses
and ketose

26. Questions/Discussion
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