2. Carbohydrates
Hydrates of carbon
Chemical composition of (CH2O)n
Primary source of energy for our bodies
Good source of fiber and vitamins
Rich in phytonutrients
Participate in many essential body functions
Two types -simple and complex
6. 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
7. 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
8. Iodine Test
Used to test for starch
Requires use of Iodine solution
dissolve iodine in potassium
iodide
How to test
1.Add Iodine solution directly to
food sample
2.A dark blue-black colour
indicates presence of starch
9. 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
Occurs throughout digestive
system
Begins in mouth
chewing releases saliva
starch broken down by
enzymes into
polysaccharides and maltose
10. 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