Chemical Tests for Carbohydrates

Question 1

Test for Ketoses
Principle: HCl + Resorcinol
Cherry Red (Ketoses)
Light Pink (Aldoses)

Answer 1

Seliwanoff’s Test

Question 2

Test for Pentoses (5C sugars)
Principle: Phlorogucinol
Red color

Answer 2

Tollens Phloroglucinol Test

Question 3

Test for 2-deoxy sugars
Brown color

Answer 3

Keller Killiani Test

Question 4

Test for All Caborhydrates
Principle: H2SO4 with a-naphthol
Purple / Violet color

Answer 4

Molisch Test (Aka: Purple Ring Test)

Question 5

Test for Reducing sugars in urine:

Answer 5

Benedict’s Test

Question 6

Test for Reducing Sugars
Principle: Cupric Sulfate
Yellow to brick Red color

Answer 6

Fehling’s Test and Benedict’s Test

Question 7

Test for Reducing Sugars
Principle: Cupric to cuprous oxide
Brick Red color
< 2 mins = monosaccharide
> 2 mins = disaccharides

Answer 7

Barfoed’s Test

Question 8

Test for Reducing Sugars
Principle: ammoniacal Silver Nitrate
Containing Aldehyde Functional Group

Answer 8

Tollens Silver Mirror Test

Question 9

Test for Reducing Sugars
Gives Browned food its distinctive flavor.

Answer 9

Maillard Reaction

Question 10

Test for: Sugars (Monosaccharides and Disaccharides)
Principle: Yellow Osazone Crystals upon
addition of Phenylhydrazine

Answer 10

Osazone Test

Question 11

In Osazone Test

1. Sunflower shape
2. Powder puff or hedgehog or cotton ball
   shape Galactose
3. Rhombic plates
4. Needle shape

Answer 11

1. Maltose
2. Lactose
3. Galactose
4. Glucose, Fructose and Mannose