Students will learn about different types of carbohydrates, the role of enzymes in breaking down complex sugars into simple sugars, and how different sugars impact our perception of sweetness and may impact human health. Grades 9-12

carbohydrate: an organic compound that is the main source of energy for the body; composed of carbon, oxygen, and hydrogen atoms

disaccharide: a sugar made of two molecules (e.g., sucrose, maltose)

enzyme: protein catalyst, which speeds up a specific chemical reaction

glycemic index: a way to measure how quickly glucose gets into the bloodstream and how food affects blood glucose levels after consumption

monosaccharide: a simple sugar molecule that cannot be broken down further into smaller molecules

polysaccharide: a sugar made of multiple molecules (e.g. glycogen, starch)

Prior to this lesson Students should be familiar with the basic nutrients needed to sustain human life including carbohydrates, proteins, lipids, vitamins, minerals, and water. Students will apply their knowledge of monosaccharides, disaccharides, and enzymes to gain a deeper understanding of carbohydrates in various forms.

Key STEM ideas:

Carbohydrates are the main source of energy for living organisms. Carbohydrates can come in the form of simple or complex sugar molecules. Complex carbohydrates must be broken down into glucose, a simple sugar, in order to be used for energy production by living organisms. While carbohydrates are always made up of sugar, not all sugars are equally sweet.

Connections to Agriculture:

Managed honey bees are a valuable agricultural commodity. Colonies of bees are rented for their pollination services and their honey is used as a natural sweetener.

A variety of different sweeteners including sugar, honey, or artificial sweeteners can be used as ingredients in food products. Honey has many applications when used as an ingredient in food products aside from its sweetness. For example, the moisture-retaining property of honey improves many baked goods such as cakes and breads and gives crusts a better texture. Honey can also be used as a dressing on roasted meat or fish as it penetrates the flesh where dry sugar will not (From A Book of Honey by Eva Crane). In using honey as an ingredient in various food products, this agricultural commodity adds nutritional value and aesthetic properties to processed foods.

1. Display the following image. Ask students what all of these foods have in common. (they all contain carbohydrates) 
2. Discuss with students what they know and have heard about carbohydrates. Use the following guiding questions:
   • Are there different types of carbohydrates? (Yes, simple and complex)
   • Do different types of carbohydrates have different levels of sweetness? (Yes)
   • Do carbohydrates give us energy? (Yes, except cellulose which we can't digest)
3. Make a list of student-generated similarities and differences between these carbohydrates. 
4. Discuss if some carbohydrates are better for us than others. Point to the picture of the honey and inform students that they will be learning more about honey. Ask students where we get honey. Show the video clip, How It's Made: Honey.

Activity 1: Introduction

1. Pass out one copy of the Honey as a Biomolecule student handout. Have students read "Part 1" and mark their best guesses for the series of true/false questions on the student worksheet about honey and sugar. This sections should not be used for grading purposes, but to illuminate student prior knowledge of honey and sugar.
2. Divide class into groups of 2-3 students. Have students read the following articles:
   • “Carbohydrates and the Sweetness of Honey”
   • “Is Honey the same as Sugar?” 
3. Ask students to compare their true-false answers with what they learned about in the articles within their groups. Did they learn anything new about honey? Did anything surprise them?

Activity 2: Comparing Carbs

1. Read the first paragraph of "Part 2" either as a whole class, in small groups, or individually. Facilitate a brief discussion with students about types of carbohydrates. Have students help make a chart on the board of the carbohydrates belonging to monosaccharides, disaccharides, and polysaccharides. To help students build vocabulary skills, discuss the Greek prefixes mono-, di-, and poly- and their meanings.
2. Guide students to evaluate what information is provided in the table in "Part 2." (Students should be able to see that carbohydrates have different levels of sweetness and disaccharides are made up of two of the monosaccharides.) Answer question #1.
3. Read the next section about digestion, or how enzymes break down larger sugar molecules. Check for understanding by asking, "Why does this happen?" (The body makes energy using glucose but not all sugars are in this form so enzymes are used to convert larger sugar molecules into usable smaller molecules. A good analogy might be that this process is like converting a $50 bill into smaller change so that it can be used in a vending machine.)
4. Use the example of breaking down of lactose into glucose and galactose to show how digested lactose has a new sweetness rating of 55 compared to undigested lactose which is 20. Have students work in pairs to answer the remaining follow-up questions. Check for student understanding and clarify when necessary.
5. Have students read the passage about how bees process nectar into honey. Ask students to draw a quick sketch of this process for understanding. Review the carbohydrate conversion taking place in honey processing. (Sucrose is broken down by invertase into fructose and glucose.) Answer the follow-up question.
6. Let students examine the ingredient list for Junior Mints. See how many types of carbohydrates students can find on the list of ingredients (Sugar (sucrose), corn syrup, confectioner's glaze (likely sugar and water), and modified food starch).
7. Note that an enzyme is added to the list of ingredients. Discuss what this enzyme will do to the sweetness of the carbohydrates (Increase it, similar to what happens to honey).

Activity 3: Developing a Food Product with Honey

1. Review with students that honey is an agricultural product made by bees. Food scientists will sometimes select honey as a sweetener because of its unique properties.
2. Divide students up into groups of 3-4 students. Explain that their task is to create a new food product using honey as one of the ingredients.
3. As outlined in the student handout, each group must come up with a product name, identify a core audience for their product, determine what their packaging will look like, decide on ingredients, and draw a sketch of their food product. Lastly, they will list three reasons why they might choose to include honey. 

After conducting these activities, review and summarize the following key concepts:

• Honey is produced by bees. Bees are an important element in agriculture and our food. They pollinate flowers as well as produce honey.
• The process of food product development is important in the field of food science.
• Knowledge of biology, chemistry, and chemical engineering play important roles in developing new and improved food products to meet our nutritional needs.

1. Honey production value in U.S. in 2014 (USDA NASS)
2. Background info on honey from The Book of Honey by Eva Crane

Author Affiliations:

• Burke Morrow: Lincoln East High School, Lincoln, NE
• Erin Ingram: University of Nebraska-Lincoln, IANR Science Literacy Initiative, National Center for Agricultural Literacy

• Everything is Chemical
• Food Chemistry Experiments
• Gourmet Lab: The Scientific Principles Behind Your Favorite Foods
• Honey Bee Study Prints
• Imported Food Safety
• TedTalk- The First 21 Days of a Bees Life
• That's So Sweet! – A Look at Honey Production in the Twin Cities
• Utah State University Bee Lab