Experiment 8. The hydrolysis of starch with hydrochloric acid PDF

Experiment 10 – Enzymes

Starch will not react with Benedict's reagent so the solution will remain In part 4

PRODUCTION OF BIO-ETHANOL FROM POTATO STARCH

Table (2) shows the qualitative analysis of reducing sugars after acid hydrolysis or (scarification) of potato starch wastes by using. Benedict's test. The

Qualitative analysis of Carbohydrates II

Benedict's test and Seliwanoff's test lable the tube (Benedict. +HCl) and Write your observation and discuses each result. Page 17. Experiment 3:Hydrolysis ...

Experiment 11 – Carbohydrates

Barfoed's test is similar to Fehling's test except that in Barfoed's test

Qualitative analysis of carbohydrates II

1-Sucrose hydrolysis Test: Objective: To identify the products of hydrolysis 6-From the tube which contain only sucrose take 2 ml to do Benedict's test only ( ...

Chem 11 Lab Manual

When starch is hydrolyzed and broken down to small carbohydrate units the iodine will not give a dark blue (or purple) color. The iodine test is used in this

Laboratory Manual of Biochemistry for 2nd year Biotechnology 1st

7- Perform the Benedict's test on the starch solution. Hydrolysis of Starch with an Enzyme: 1. Add a tiny amount of amylase to a test tube containing 10.0 mL.

1 BCH302 [Practical]

glycogen. Page 7. 7. Page 8. 8. Sucrose hydrolysis Test. The Iodine/Potassium Iodide Test: for polysaccharides. Hydrolysis of Starch. Benedict's test only ( ...

V HYDROLYSIS OF STARCH BY SALIVARY AMYLASE

Carbohydrates to be tested: hydrolyzed starch and fresh starch solutions. 1. In each of two medium test tubes place 2 droppers full of Benedict's reagent and 1

Experiment 10 – Enzymes

If the amylase is inactivated it can no longer hydrolyze starch

Qualitative analysis of Carbohydrates II

by hydrolysis and lost one Plants synthesize two forms of starch amylose

Experiment 8. The hydrolysis of starch with hydrochloric acid

A 3% starch solution should be tested with Benedict's solution to see if it withstands hydrolysis after 5 minutes in a water bath. Apparatus - per group test-

Qualitative analysis of carbohydrates II

glucose homopolymer present in animal cells is called glycogen. starch 5-From the tube containing HCl take 2ml in tow tube to do Benedict's test and.

1 BCH302 [Practical]

Sucrose hydrolysis Test. Hydrolysis of Starch. ... From the tube containing HCl take 2ml in two tube to do Benedict's test and Seliwanoff's.

V HYDROLYSIS OF STARCH BY SALIVARY AMYLASE

Carbohydrates to be tested: hydrolyzed starch and fresh starch solutions. 1. In each of two medium test tubes place 2 droppers full of Benedict's reagent and 1

Enzyme Systems in Stylonychia pustulata III. Hydrolysis of Starches

the hydrolysis of starch and glycogen. MATERIALS AND METHODS reagent. The intensity of coloration pro- duced by the Benedict's reagent was ap-.

Chem 11 Lab Manual

or a polysaccharide (starch or cellulose) which consists of thousands of with Benedict's or Fehling's reagent as well as hydrolyzed amylose (a mixture ...

Experiment 11 – Carbohydrates

reagent. Reducing monosaccharides react quickly with Barfoed's reagent will also hydrolyze a sample of starch and then test it for the presence of both ...

1 AMYLASE TEST (STARCH HYDROLYSIS)

So this is basically two tests: (a) growth on 40% bile and (b) hydrolysis of esculin. • Test procedure. 1. Obtain a bile esculin slant. With a sterile loop

Experiment 15 Carbohydrates - Moorpark College

Acid–Catalyzed Hydrolysis of Starch 1 Place 5 0 mL of starch solution in a 150 x 15 – mm test tube and add 1 0 mL of dilute sulfuric acid (3 M H 2 SO 4) Mix it by gently shaking the test tube Heat the solution in a boiling water bath for about 5 min 2 Using a clean medicine dropper transfer about 3 drops of the starch solution into a

Experiment 10 – Enzymes - Laney College

Enzymatic hydrolysis of starch occurs at the ?-14- and ?-16-glycosidic linkages that hold the starch polymer together Alpha-amylase hydrolyzes the ?-14-glycosidic linkages of starch It attacks the interior of polysaccharide chains resulting in the formation of a mixture of fragments of 5 to 9 units of the alpha configuration (10)

V HYDROLYSIS OF STARCH BY SALIVARY AMYLASE - Chem21Labs

Benedict's test is the disappearance of the blue color of the solution and the appearance of a brick-red precipitate Monosaccharides and disaccharides that contain aldehydes or -hydroxy ketones will give a positive Benedict's test as these groups are easily oxidized to carboxylic acids

EXPERIMENT 8 Properties of Carbohydrates: Solubility

Hydrolysis of Starch On a spot plate place 1 drop of dilute iodine solution in each depression In a large test tube place 20 mL of 1 cooked starch suspension Heat in a boiling water bath and when hot add 2 mL of 6 M hydrochloric acid (HCl)

Experiment 10 – Enzymes - Laney College

Jan 10 2012 · In the presence of amylase a sample of starch will be hydrolyzed to shorter polysaccharides dextrins maltose and glucose The extent of the hydrolysis depends on how long it is allowed to react – if the starch is hydrolyzed completely the resulting product is glucose

Searches related to hydrolysis of starch benedict+s test filetype:pdf

2 Explain how iodine and Benedict’s reagent indicate whether starch digestion has occurred 3 State how the digestion of starch is affected by doing the following: a presence of amylase b temperature c time Key Terms You Should Know: Digestion amylase Hydrolysis IKI (iodine) test Starch Benedict’s reagent test Maltose

How do you test for amylase and starch in a lab?

8. Place 4 mL of 1% starch solution in each of three clean test tubes. Place 4 mL of amylase solution in 3 separate clean test tubes (so you will have a total of six test tubes: 3 containing starch and 3 containing enzyme).

How do you make Benedict’s solution from glucose solution?

Place 3 mL of 1% glucose solution in a test tube. Add 2 mL of Benedict’s solution and heat for 3-4 minutes in a boiling water bath. The reaction should produce a red-orange solid.

Does hydrolyzed sucrose give a positive test with Benedict's reagent?

Hydrolyzed sucrose (a mixture of D–glucose and D–fructose) will give a positive test with Benedict’s or Fehling’s reagent as well as hydrolyzed amylose (a mixture of glucose and glucose–containing oligosaccharides).

How does Benedict's reagent test for glucose?

You will also test for the presence of glucose in the samples using Benedict’s reagent. When a blue solution of Benedict’s reagent is added to a glucose solution, the color will change to green (at low glucose concentrations) or reddish-orange (at higher glucose concentrations).

Experiment 8. The hydrolysis of starch with hydrochloric acid (a) Prepare a water bath by half filling a 250 cm3 beaker with warm water and heating it to boiling point on a tripod and gauze, with a Bunsen burner. When the water boils, reduce the flame to keep the water at boiling point. (b) Label four test-tubes 1-4. (c) Copy the table given below into your notebook. (d) In each tube place 5 cm3 3% starch solution. (e) Using a syringe or graduated pipette, add 3 cm3 Benedict's solution to the starch solution in tube 1 and place the tube in the boiling water bath for five minutes. (f) Rinse the syringe or pipette and use it to add 1 cm3 dilute hydrochloric acid to the starch solution in each of tubes 2, 3 and 4. Note the time and place all three tubes in the water bath. (They will be removed at five, ten and fifteen minutes respectively). (g) Remember to remove tube 1 from the water bath after five minutes if you have not already done so. (h) After five minutes, remove tube 2 from the water bath and cool it under the tap. Neutralize the acid by adding solid sodium bicarbonate, a little at a time, until the addition of one portion produces no fizzing. Place tube in the rack and return to tube 3. (i) After ten minutes in the water bath, remove tube 3, cool and neutralize the contents as described in (h). Place the tube in the rack. (j) After fifteen minutes in the water bath, remove tube 4; cool and neutralize as before, and place it in the rack. (k) With a dropping pipette, remove a sample of the liquid from tube 2 and place 3 drops on a spotting tile. Rinse the pipette and repeat the procedure for tubes 3 and 4. Add one drop of dilute iodine to each drop of liquid on the tile. (l) Rinse the syringe or pipette and use it to place 3 cm3 Benedict's solution in each of tubes 2, 3 and 4. Return all three tubes to the water bath and heat for five minutes. After this time replace the tubes in the rack and allow them to cool sufficiently to handle. Hold the tubes to the light to compare the colours of the solutions and compare also the colours and relative quantities of any precipitates.

Tube Containing Appearance

with iodine

Colour of

solution

Colour of

precipitate

Relative

quantity of precipitate

1 3% starch solution only

2 3% starch solution boiled for

5 min with dilute HCL

3 3% starch solution boiled for

10 min with dilute HCl

4 3% starch solution boiled for

15 min with dilute HCl

Enzymes 8.01

Experiment 8. Discussion

1 What was the point of adding sodium bicarbonate to tubes 2, 3 and 4?

2 What food substance is Benedict's solution a test for?

3 At the end of the experiment, what food substance was present in tubes 3 and 4 that

was not there at the beginning?

4 What evidence have you that this substance was not present at the beginning of the

experiment?

5 How do you account for the difference, after testing with Benedict's solution, between

tubes 2, 3 and 4?

6 How do you interpret the results of the iodine test in tubes 2, 3 and 4?

7 What relationship is there between the interpretation of the results with the iodine test and the

Benedict's test?

8 The starch molecule consists of a long chain of carbon atoms with hydrogen and oxygen

atoms attached. Sugars, such as glucose, consist of six carbon atoms with hydrogen and oxygen atoms attached. (*many H atoms omitted) Assuming that the hydrochloric acid is acting only as a catalyst in the reaction, attempt an explanation of the chemical change which takes place in tubes 3 and 4.

9 In this experiment, the emphasis is on the conversion of starch to something else using

hydrochloric acid. What control experiment would have to be carried out to show that hydrochloric acid played a significant part in bringing about this change?

Enzymes 8.02

part of a starch molecule* glucose molecule*

Starch and

hydrochloric acid remove after minutes cool add sodium bicarbonate test with test sample with iodine Experiment 8. The hydrolysis of starch with hydrochloric acid - preparation Outline. The experiment illustrates the conversion of starch to a reducing sugar by the action of hydrochloric acid at boiling point. The longer the starch is exposed to the acid the further hydrolysis proceeds. The experiment is intended to show the contrast with enzymes, which do not need high temperatures and prolonged exposure to reagents and give a quick reaction. Prior knowledge. Benedict's reaction, starch/iodide reaction.

Advance preparation and materials-per group

3% starch solution, freshly prepared* 25cm3 sodium hydrogencarbonate (bicarbonate)

Benedict's reagent 20 cm3 powder about 5 g dilute hydrochloric acid, 2M or 10% iodine solution (dilute) 5 cm3 + (bench strength) 5 cm3 * NOTE. Some brands of starch are readily hydrolysed and might give a positive reaction with tube 1. A 3% starch solution shou hydrolysis after 5 minutes in a water bath.

Apparatus - per group

test-tube rack and 4 test-tubes tripod

4 labels or spirit marker gauze

graduated pipette or syringe 10 cm3 heat mat

250 cm3 beaker spatula for adding sodium hydrogencarbonate

Bunsen burner dropping pipette (if not supplied with iodine bottle)

- per class clock

Time The experiment needs from 30-45 minutes

+ See instructions for making dilute iodine on p. 01

Enzymes 8.03

Experiment 8. Discussion - answers

1 The hydrogencarbonate neutralizes the hydrochloric acid which would otherwise interfere with

Benedict's reagent.

2 Benedict's solution is a test for reducing sugars.

3 Tubes 3 and 4 should have a red precipitate, indicative of a reducing sugar.

4 Tube 1, containing starch solution, should have given little or no colour change with Benedict's

solution.

5 Tube 4 will probably have a more intense red colour or a more dense precipitate than the

others, indicating that a greater quantity of reducing sugar has been formed. The liquid in tube 2 may still be blue, indicating unchanged Benedict's solution.

6 The blue colour is progressively less intense or absent altogether in tube 4 indicating that

starch is 'disappearing'.

7 In tube 4, at least, starch has disappeared and sugar has appeared. It could be that:

(i) Hydrochloric acid has changed starch into sugar. (ii) Hydrochloric acid has combined with starch to form sugar. (iii) Starch has converted hydrochloric acid to sugar.

8 If students are not overwhelmed by the sight of the structural formulae they might notice that

by breaking the starch chain at the -0- linkages, adding H- to one side and -OH to the other, glucose molecules would be produced. The possibility of disaccharides is ignored at this juncture.

9 To show that starch solution is not converted to sugar by simply boiling it, a control should be

carried out by boiling 5 cm3 3% starch solution for 10 minutes and then testing with Benedict's reagent.

Enzymes 8.04

quotesdbs_dbs7.pdfusesText_13

[PDF] Experiment 8. The hydrolysis of starch with hydrochloric acid

How do you test for amylase and starch in a lab?

How do you make Benedict’s solution from glucose solution?

Does hydrolyzed sucrose give a positive test with Benedict's reagent?

How does Benedict's reagent test for glucose?

Tube Containing Appearance

Colour of

Colour of

Relative

1 3% starch solution only

2 3% starch solution boiled for

5 min with dilute HCL

3 3% starch solution boiled for

10 min with dilute HCl

4 3% starch solution boiled for

15 min with dilute HCl

Enzymes 8.01

Experiment 8. Discussion

1 What was the point of adding sodium bicarbonate to tubes 2, 3 and 4?

2 What food substance is Benedict's solution a test for?

3 At the end of the experiment, what food substance was present in tubes 3 and 4 that

4 What evidence have you that this substance was not present at the beginning of the

5 How do you account for the difference, after testing with Benedict's solution, between

6 How do you interpret the results of the iodine test in tubes 2, 3 and 4?

7 What relationship is there between the interpretation of the results with the iodine test and the

Benedict's test?

8 The starch molecule consists of a long chain of carbon atoms with hydrogen and oxygen

9 In this experiment, the emphasis is on the conversion of starch to something else using

Enzymes 8.02

Starch and

Advance preparation and materials-per group

3% starch solution, freshly prepared* 25cm3 sodium hydrogencarbonate (bicarbonate)

Apparatus - per group

4 labels or spirit marker gauze

250 cm3 beaker spatula for adding sodium hydrogencarbonate

Time The experiment needs from 30-45 minutes

Enzymes 8.03

Experiment 8. Discussion - answers

1 The hydrogencarbonate neutralizes the hydrochloric acid which would otherwise interfere with

Benedict's reagent.

2 Benedict's solution is a test for reducing sugars.

3 Tubes 3 and 4 should have a red precipitate, indicative of a reducing sugar.

4 Tube 1, containing starch solution, should have given little or no colour change with Benedict's

5 Tube 4 will probably have a more intense red colour or a more dense precipitate than the

6 The blue colour is progressively less intense or absent altogether in tube 4 indicating that

7 In tube 4, at least, starch has disappeared and sugar has appeared. It could be that:

8 If students are not overwhelmed by the sight of the structural formulae they might notice that

9 To show that starch solution is not converted to sugar by simply boiling it, a control should be

Enzymes 8.04