Exercise 6 Hydrolysis of Starch

Question 1

• is a white, granular, organic chemical that is produced by all green plants
  - it is a white, tasteless powder insoluble in cold water, alcohol, or other solvents.

Answer 1

Starch

Question 2

s a polysaccharide comprising glucose monomers joined in α 1,4 linkages

Answer 2

Starch

Question 3

The simplest form of starch is the________,______________is the branched form.

Answer 3

linear polymer amylose; amylopectin

Question 4

is manufactured in the green leaves of plants from excess glucose produced

Answer 4

Starch

Question 5

Tong or Test tube holder

Answer 5

Tong or Test tube holder

Question 6

Hydrolyzing Starch using Heat

Answer 6

Starch mixed with Benedict’s reagent (without heat) - no positive result; negative result is blue

Starch mixed with Benedict’s reagent (with heat) - positive result is yellow/red

Question 7

Hydrolyzing Starch using Hydrochloric acid

Answer 7

Starch mixed with Hydrochloric acid, Sodium bicarbonate, and Benedict’s Reagent (with heat) - positive result is red

Starch mixed with Benedict’s reagent (without heat) - no positive result; negative result is blue

Question 8

What is the purpose of adding sodium bicarbonate?

Answer 8

Sodium bicarbonate or most commonly known as “baking soda” can promote the gelatinization of starch. The purpose of adding sodium bicarbonate in the experiment is to neutralize the hydrochloric acid, for us to observe how it disintegrates and disrupt polysaccharides starch compounds and free sugar molecules in the solution.

Question 9

Why is starch essential for the body?

Answer 9

Starch is our main carbohydrate source, essential to a balanced diet. Additionally, starch provides us with a source of energy for humans. The body digests starch metabolizing it into glucose, which enters the bloodstream and circulates throughout the body. It is also the primary source of a range of nutrients we consume.

Question 10

List of Foods that are excellent sources of starch

Answer 10

Cornmeal
Rice krispies
Pretzels
Pasta
Saltine crackers
Oats
Whole-wheat flour
Instant noodles
Rice
Breads

Question 11

What is the effect of heat on starch?

Answer 11

When starch is heated, the starch molecules are broken down into smaller glucose subunits. Thus, heat completes the hydrolysis of starch by yielding sugar D glucose, which is then subjected to interpretation by the use of Benedict’s reagent to determine the concentration of reducing sugars.