Starch is made of many glucose monomers.

Glucose

So, why aren’t starchy foods (bread, potatoes, pasta etc..) sweet, as glucose is?Suggest at least one idea.

QUIZ: Brace/Arrow maps.

Demonstration: How to test for Starch, Glucose and Protein in foods.

Foods to be tested: Starch powder, Sugar powderStarch, sugar solutions, egg yolk.

Write:1. Describe the procedures.2. What does a positive reaction

look like?3. Write the results of the tests.

1. Testing for Protein: Buiret Reagent

Egg Yolk

Apple Juice

Starch

Color before

Color After Protein?

2.Testing for Sugar: Benedict Reagent

Egg Yolk

Apple Juice

Starch

Color before

Color After Sugar?

2.Testing for Starch: Iodine Reagent

Sugar powder

Corn Starch

Color before

Color After Starch?

1. What could be the benefit of testing foods for protein, sugar and starch? 2. Benedict reagent changes color in the presence of most sugars. How do you expect Benedict to react with a starch suspension? Explain.

FOOD LAB – PART ONE

Trying out the reagents yourself!

Today you will test the following samples for protein, sugar and starch:Apple Juice Starch powderMilk Sugar powderCornStarch in water Baking SodaEgg White Baking Powder

In your group – discuss: A. What kind of results do you

expect to get?B. How will you organize the

data that you will collect?C. How will you manage the way

group members will work together?

Go, do it!

In the previous lab we have used Benedict and Biuret reagents to test for sugar and protein in Juice, cornstarch, Gelatin and egg white.Write at least five lines about the lab so far. This could include (but isn’t limited to): Purpose, questions, observations, impressions, more.

Initial your name next to your response.

Write around: Pass your notebooks around in the group. Write in each other’s notebooks – confirm or correct, add details, ask questions, anything relevant! 1 minutes per response.

Sharing with the class: How did you record your observations?(Data Collection)

Sharing with the class – So… why did we do this lab on Thursday? (Research question)

Sharing with the class: What did we learn? (Conclusion)

1. Pepsi claims, that Diet 7-Up is sugar free. What do we need to do in order to check that they are not lying to us? Be specific.

2. If they are telling the truth, how will the test result look like? Be specific.

Go, Test it!

MaterialsLab Stations: Benedict reagent, Test Tubes, racks, holdersHot water

Center table: Regular 7-UpDiet 7-Up

Class Results:

Group:

7-UpDiet 7-Up

1 2 3 4 5 6 7 8 9 10

Period 1

Class Results:

Group:

7-UpDiet 7-Up

1 2 3 4 5 6 7 8 9 10

Period 2

Class Results:

Group:

7-UpDiet 7-Up

1 2 3 4 5 6 7 8 9 10

Period 4

Class Results:

Group:

7-UpDiet 7-Up

1 2 3 4 5 6 7 8 9 10

Period 5

Class Results:

Group:

7-UpDiet 7-Up

1 2 3 4 5 6 7 8 9 10

Period 6

What is going on ?

Formulate a possible explanation to the class results.

Propose a means to test your explanation in our lab.

First group that ‘get’s it – wins candy! not to mention points..