Biochemistry Laboratory

NAME: _______________________ GROUP NUMBER:____4__________ SCHEDULE:_7:30-12:00 TTh________

DATE:_______________ RATING:

Activity No. 7 TEST FOR CARBOHYDRATES FOUND IN THE HOUSEHOLD

I.

OBJECTIVES a. To be able to test what type of carbohydrate is present in the different household materials b. To be able to identify the different type of carbohydrates using different specific chemical test.

II.

MATERIALS Household materials Pineapple Oats Avocado Corn Sugar Cane

III.

Laboratory apparatus 20 test tubes 2 test tube rack 2 test tube holder 2 10ml. graduated cylinder 4 dropper 1 mortar & pestle Water bath Tripod Bunsen burner Wire gauze

Chemicals Molish reagent Benedict’s reagent Tollen’s reagent Iodine solution Conc. Sulfuric acid

PREPARATION OF HOUSEHOLD MATERIALS 1. PINEAPPLE a. Get a portion of an over-ripe pineapple b. Extract 10 ml. of pineapple juice c. Place 1 ml. of pineapple extract in 4 separate test tubes 2. OATS a. Cook oats as instructed in the label b. Measure 10 ml of the cooked oats d. Place 1 ml. of cooked in 4 separate test tubes 3. Avocado a. Using a blender, blend avocado to make juice b. Measure 10 ml of avocado juice. c. Place 1 ml. of avocado juice in 4 separate test tubes. 4. Corn a. Cook corn with water b. Mash corn with mortar and pestle

c. Extract 5 ml of corn juice d. Place 1 ml. of corn extract in 4 separate test tubes 5. Sugar Cane a. Cut sugar can into cubes b. Pound sugar cane with mortar and pestle c. Extract 5 ml of juice d. Place 1 ml. of cane extract in 4 separate test tubes IV.

PROCEDURE A. GENERAL COLOR TEST (MOLISCH TEST) 1. To 5 separate test tubes each containing the different household materials, add 5 drops of molisch reagent. Mix well. 2. Incline the test tube and slowly and carefully add 1 ml. of conc. sulfuric acid (CAUTION!) down the side of the tube to form a layer below the solution. (NOTE: It is very important that the lip of the graduated cylinder be touching the inner top of the test tube containing the carbohydrate and that the acid be poured slowly.) 3. Note the color formed at the junction of two liquids. Some reaction may take as long as 15 minutes to 20 minutes, so proceed with the next part of the experiment 4. Record your result at the observation data sheet under Molish test. B. TEST FOR REDUCING SUGAR 1. BENEDICT’S TEST a. Add 1 ml. of Benedict’s reagent to 5 separate test tubes each containing the different household materials. b. Shake tube thoroughly and place all tubes in a boiling water bath. c. Heat for 5 minutes and observe what happens. d. Record your result at the observation data sheet under Benedict’s test. 2. TOLLEN’S TEST a. Add 2 ml. of Tollen’s reagent to 5 separate test tubes each containing the different household materials. b. Heat for 5 minutes and observe what happens. c. Record your result at the observation data sheet under Tollen’s test. C. REACTION WITH IODINE 1. To 5 separate test tubes each containing the different household materials, add 5 drops of iodine solution. 2. Observe and record your result under Reaction with Iodine (without heating). 3. If there are no changes, gently heat the solution. Observe for changes and record your observation under Reaction with Iodine (with heating).

OBSERVATION DATA SHEET HOUSEHOLD MATERIALS

MOLISCH TEST RESULT

HOUSEHOLD MATERIALS

TOLLEN’S TEST RESULT

Pineapple

Pineapple

Oats

Oats

Avocado

Avocado

Corn

Corn

Sugar Cane

Sugar Cane

BENEDICT’S TEST HOUSEHOLD RESULT

REACTION WITH IODINE (without heating) HOUSEHOLD RESULT

Pineapple

Pineapple

Oats

Oats

Avocado

Avocado

Corn

Corn

Sugar Cane

Sugar Cane

MATERIALS

HOUSEHOLD MATERIALS

REACTION WITH IODINE (with heating) RESULT

Pineapple Oats Avocado Corn Sugar Cane

V.

MATERIALS

GENERALIZATION