Name: Hồ Thanh Trúc

ID : 08125263

Date: 27th Octorber, 2010

REPORT 1

carbohydrateS

I) PURPOSE:

To become familiar with the reducing or nonreducing nature of carbohydrates.

To experience the enzyme-catalyzed and acid-catalyzed hydrolysis of acetal groups.

II) REPORT SHEET

Carbohydrates in general - Molisch's Test

Test tube no.

Substance

Molishch's test (positive or negative)

1

Glucose

Negative

2

Starch

Negative

3

Water (control)

Negative

Reducing or nonreducing carbohydrates

Test tube no.

Substance

Reducing or nonreducing carbohydrates

1

Glucose

Reducing

2

Fructose

Reducing

3

Sucrose

nonreducing

4

Lactose

Reducing

5

Starch

nonreducing

Ketose or aldose carbohydrates

Test tube no.

Substance

Ketose or aldose carbohydrates

1

Glucose

Aldose

2

Fructose

Aldose

3

Sucrose

Ketose

4

Maltose

Aldose

Hydrolysis of carbohydrates

Hydrolysis of sucrose (acids versus base catalysis)

Sample

Condition of hydrolysis

Benedict's reagent (positive or negative)

1

Acidic (H2SO4)

Positive

2

Basic (NaOH)

Negative

Hydrolysis of starch (enzyme versus acid catalysis)

Sample

Condition of hydrolysis

Iodine test (positive or negative)

1

Enzymatic (amylase)

Negative

2

Acidic (H2SO4)

Positive

Acid catalyzed hydrolysis of starch

Test tube no.

Heating time (min.)

Iodine test (positive or negative)

1

5

Positive

2

10

Positive

3

15

Positive

4

30

Negative