CarbohydratesDone by: Valerie, Jilian, and Catherine

Carbohydrates

Hydrates of carbon

Chemical composition

of (CH2O)n

Primary source of

energy for our bodies

Good source of fiber

and vitamins

Carbohydrates

Rich in phytonutrients

Participate in many

essential body

functions

Two types - simple and

complex

Simple Carbohydrates

Fruits, milk, and

vegetables

Simple sugars found in

refined sugar foods

e.g. sweets, cakes

Monosaccharides &

disaccharides

Monosaccharides

Simplest carbohydrate

Basic sugar unit

Three variations: glucose, fructose, galactose

Monosaccharides

Glucose Fructose Galactose

Mild sweet

flavour

Sweetest

sugar

Hardly tastes

sweet

Known as

"blood sugar"

Found in fruits and

honey

Rarely found

naturally alone

Essential energy

source

Added to soft

drinks, cereals

Disaccharides

Made up of two monosaccharides

Formed through condensation

Taken apart via electrolysis

Three types: sucrose, lactose, maltose

Disaccharides

Sucrose Lactose Maltose

Fructose and

glucose

Glucose and

galactose2 Glucose units

Found in table

sugarFound in milk Not abundant

Produced when

starch breaks

down

Complex Carbohydrates

Provide vitamins,

minerals, and fiber

Found in breads,

pasta, and starchy

vegetables

Polysaccharides

Polysaccharides

Chains of monosaccharides

Glycogen and starch

built purely on glucose

Fiber

variety of monosaccharides and carbohydrate

derivatives

Glycogen

Limited in meat and not found in plants

Not an essential source of carbohydrates

Glucose is always stored as glycogen

easy release of energy in long chains

Starch

Found in plants and stored in plant cells

Created through photosynthesis

Body hydrolyzes plant starch into glucose

Fiber

Structural parts of plants

Fibers are not broken down during digestive

process

Two types - soluble and insoluble

Fiber

Soluble Insoluble

Easily digested by

bacteria in colonPromotes bowel movement

Associated with

protection against heart

disease and diabetes

Alleviates constipation

Found in legumes and fruitsFound in grains and

vegetables

Testing for

Carbohydrates

Testing for

CarbohydratesBenedict's Test for

Reducing Sugars

Iodine Test for Starch

Benedict's Test

Used to test for presence of reducing sugars

all monosaccharides

disaccharides: lactose and maltose

Requires use of Benedict's Reagent

prepared from CuSO4, NaOH, tartaric acid

Benedict's Test

1. Dissolve food sample in water

2. Add small amount of Benedict's Reagent

3. Heat in water bath from 4 - 10 minutes

4. Positive test indicated by a brick red solution

How can we test for

Sucrose?

Testing for Sucrose

Sucrose is a non-reactive substance

does not react with Benedict's Reagent

Break down with dilute Hydrochloric Acid before

testing

broken down into fructose and glucose

Iodine Test

Used to test for starch

Requires use of Iodine

solution

dissolve iodine in

potassium iodide

Iodine Test

1. Add Iodine solution directly to food sample

2. A dark blue-black colour indicates presence of

starch

Carbohydrate Digestion

Carbohydrate Digestion

Break down carbohydrate into glucose

able to be absorbed and used by body

Starch - extensive breakdown

Disaccharides - broken down once

Monosaccharides - need not be broken down

Carbohydrate Digestion

Occurs throughout digestive system

Begins in mouth

chewing releases saliva

starch broken down by enzymes into

polysaccharides and maltose

Digestion in the

Stomach

No enzymes available for starch breakdown

Acid does minor breakdown

Fibers provide feeling of "fullness"

Digestion in the

Small Intestine

Primary site of carbohydrate digestion

Pancreatic enzyme reduces carbohydrates into

glucose chains or disaccharides

Specific enzymes are present to fully reduce

disaccharides

Digestion in the

Large Intestine

1 to 4 hours for sugars and starches to be fully

digested

Only fibers remain

retain water to soften stool

In Summary

Carbohydrates are

important for daily

living

Digestion is a complex

and thorough process

Can be tested using

various methods

Thank You!