Linda Wozniewskilwoz@iun.edu

Sharon Ramsey

Food Chemistry (B)

Disclaimer This presentation was prepared using

draft rules.  There may be some changes in the final copy of the rules.  The rules which will be in your Coaches Manual and Student Manuals will be the official rules

Safety Students must wear:

Closed shoes Slacks or skirts that come to the ankles Lab coat or lab apron Indirect vent or unvented chemical

splash proof goggles. No impact glasses or visorgogs are permitted

Long-Sleeved Shirt (if wearing a lab apron)

What Students MUST Bring Impounded

None Non-Impounded

Homemade viscometer Standard curve A writing instrument

What Students May Bring Non-programmable Calculator 1 sheet of paper on which anything is

acceptable

What Supervisors Will Supply Everything the student will need

This may include: Glassware Reagents Balances Hot plates Thermometers Probes Magnets Stirrers

Main Focus Chemistry of Food How to prepare students Experiment ideas Resources

Chemistry of Food a. Identify the sources of and understand the role of

lipids, carbohydrates and proteins typically found in cookies, and use tests to identify these compounds, including the Benedict’s, Iodine and Brown Bag tests.

b. When given samples of sweeteners, use the Benedict’s test to identify reducing sugars.

c. When given samples of cupcake ingredients, use the Biuret test to identify and rank the ingredients by protein content.

d. When given formulations, processes, and finished cupcakes, identify the error in the cupcake formulation and/or process used.

e. Use standard labeling regulations to produce a label from information given.

f. Determine the moisture loss and density of cupcakes.

g. Identify leavening agents using chemical tests, and understand the role of the leavening agents in baked cupcakes.

Before your event Research! Understand the science

first Experiments – eight mandatory

(includingViscotester Production and Standard

Curve)

Ingredients The right ingredients

Liquids…. Lipids Leavening agents Flours Sweeteners

Must understand WHY you are using the ingredient…what function does it provide?

Teams are limited to listed ingredients

List of Approved IngredientsLiquids Lipids Leavening agents Flours Sweeteners

Water, WholeMilk (Cow or Goat), Skim Milk, Buttermilk, Almond Milk, Soy Milk, Coconut Milk, Eggs, Egg Substitute

Vegetable oils,Shortening, Butter Margarines,Chocolate

Baking powderBaking sodaCream of tartar

FlavoringSalt

All purpose white flourBread flourCake flourWhole wheat flourAlmond flourCoconut flourCorn FlourRice Flour

SugarBrown sugar Honey Sucralose AspartameVanillaFor State & NationalsFructosePowdered Sugar

Each recipe must contain at least one egg or one egg substitute equivalent.

Carbohydrates Carbohydrates

Cox(H2O)y carbon along with hydrogen and oxygen in the same ratio as water

Basic unit – monosaccharide

Multiple units – disaccharide (2) trisaccharide (3) oligosaccharide (2-10) polysaccharide (>10)

Carbohydrates Sugars

Monosaccharides

Glucose, Fructose

Disaccharides Lactose (glucose

and galactose) -milk

Maltose (glucose and glucose) -

Sucrose (glucose and fructose –table sugar

Reducing sugarsExamples: glucose, lactose, fructose

Non-reducing sugar contains no hemiacetal groups.

Example: sucrose

CarbohydratesPolysaccharides Examples:

starch - glucose polymers, found in plants cellulose –found in plant fibers, insoluble Pectin-units are sugar acids rather than simple

sugars, found in vegetables and fruits Branched vs. linear

Starches are a mixture of branched (amylopectin) and linear (amylose) polysaccharides

Tests for carbohydrates Benedicts test for sugars

Iodine test for starch

Positive Reaction

Benedict’s Test The Benedict's test allows us to detect the presence of

reducing sugars (sugars with a free aldehyde or ketone group).  All monosaccharides are reducing sugars.  Some disaccharides are also reducing sugars.  Other disaccharides such as sucrose are non-reducing sugars and will not react with Benedict's solution.  Starches are also non-reducing sugars. 

The copper sulfate (CuSO4) present in Benedict's solution reacts with electrons from the reducing sugar to form cuprous oxide (Cu2O), a red-brown precipitate.

The final color of the solution depends on how much of this precipitate was formed, and therefore the color gives an indication of how much reducing sugar was present if a quantitative reagent was used.

With increasing amounts of reducing sugar the result will be:

green yellow orange red

Iodine Test The Iodine test is used to test for

the presence of starch. Iodine solution – Iodine is dissolved in

an aqueous solution of potassium iodide - reacts with starch producing a deep blue-black color.

Although the exact chemistry of the color change is not known, it is believed that the iodine changes the shape of the starch to change the color

Lipids Present as fats extracted from plants

or animals (butter, vegetable oil) or as constituents of food (chocolate)

Contributions to foods: texture and flavor

Contain only Carbon, hydrogen and oxygen

Most common form for lipid in foods is as a triglyceride

What difference in texture would you see substituting vegetable shortening or vegetable oil for butter in the formulation?

Saturated Lipids (Fats) Saturated fats

have no double bonds in any of the fatty acid chains in the triglyceride hence it is saturated with hydrogen.

Considered not heart healthy

Food Lauric acid

Myristc acid

Palmitc acid

Stearic acid

Coconut oil

47% 18% 9% 3%

Butter 3% 11% 29% 13%

Dark chocolate

0% 0% 34% 43%

Eggs 0% 0.3% 27% 10%

Soybean oil

0% 0% 11% 4%

Unsaturated Fats (Lipids) Have one

(monounsaturated) or more (polyunsaturated) carbon chains

This means there are one or more double bonds in the chain

Lipids http://

www.wellsphere.com/healthy-cooking-article/butter-vs-shortening-in-baking/156136

Conversion between solid structure to a liquid state is called the melting point

How would changing the melting point of the lipid used change the cookie texture?

Brown Bag Test

Proteins Proteins are made up of amino acids

essential and nonessential

Contains Nitrogen Protein can be found in the flour, egg

and milk as well as other ingredients.

Proteins Biuret Test The Biuret Reagent is

made of sodium hydroxide and copper sulfate. The blue reagent turns violet in the presence of proteins, and the darker the purple color, the more protein is present.

Biuret’s Reagent is unstable, but can be mixed on the spot using NaOH & Benedicts

Leavening agents Used to produce a gas that

'lightens' dough or batter. used to raise baked goods. water a leavening agent (pie

crusts, some crackers) air incorporated into batter

(angel and sponge cakes) expand when heated and

cause the raising of the dough or batter when gas is trapped in matrix of gluten and starch from flour

Leavening agents Baking soda

-NaHCO3 Needs moisture plus an acid

source such as vinegar, citrus juice, sour cream, yogurt, buttermilk, chocolate, cocoa (not Dutch-processed), honey, molasses (also brown sugar), fruits or maple syrup to react

used to neutralize acids in foods around 4 times as strong as

baking powder can cause soapy flavor in high

amounts

Leavening agents Baking powder

NaHCO3 plus acidifier(s) and drying agent (usually an acid salt and cornstarch)

can cause acidity and/or bitter off-flavor two acidifiers used in double acting to produce

CO2 in two steps Reacts when moistened and also reacts when

heated double-acting is the only commercial baking

powder available today.

Standard Recipe • 2 1/4 cups flour

• 1 1/3 cups sugar• 3 teaspoons baking powder• 1/2 teaspoon salt• 1/2 cup shortening• 1 cup milk• 1 teaspoon vanilla• 2 large eggs

Effect of IngredientsBatch # Flour Leavening agent Sweeten

erLiquid Egg lipid Salt Vanill

a1 2 ¼ cups

 3 tsps. baking powder

1 1/3 Cup

1 cup milk or sub.

2 large or substitute

none ½ tsp.

1 tsp.

2 2 ¼ cups  

3 tsps. baking powder

1 1/3 Cup

1 cup milk or sub.

2 large or substitute

3 Tbsp oil ½

tsp.none

3 2 ¼ cups 

None 1 1/3 Cup

1 cup milk or sub.

2 large or substitute

3 Tbsp oil ½

tsp.1 tsp.

4 2 ¼ cups 

3 tsps. baking soda 1 1/3 Cup

1 cup milk or sub.

2 large or substitute

3 Tbsp oil ½

tsp.1 tsp.

5 2 ¼ cups 

3 tsps. baking powder

1 1/3 Cup

2 cup milk or sub.

2 large or substitute

3 Tbsp oil

½ tsp.

1 tsp.

6 2 ¼ cups 

3 tsps. baking powder

2 1/3 Cup

1 cup milk or sub.

2 large or substitute

3 Tbsp oil ½

tsp. 1 tsp.

Mixing Technique Incorporate

ingredients Hydrate dry

ingredients Experiment set

2 explores the best method to mix the batter

Standard Mixing Preheat oven to 350 degrees.  Line cupcake pans with

paper liners. Combine flour, sugar, baking powder, and salt in a

large mixing bowl.  Add shortening, milk, and vanilla.  Beat for 1 minute on medium speed.  Scrape side of bowl with a spatula.

Add eggs to the mixture.  Beat for 1 minute on medium speed.  Scrape bowl again.  Beat on high speed for 1 minute 30 seconds until well mixed.

Spoon cupcake batter into paper liners until 1/2 to 2/3 full.

Bake for 20 to 25 minutes or until toothpick inserted in center comes out clean.

Cool 5 minutes in pans then remove and place on wire racks to cool completely.

Mixing TechniqueBatch # Step 1 Step 2 Step 3 Step 41 Mix dry ingredients

together

Add liquidingredients

Using spoon, stiringredients for 30 seconds

Add egg. Use spoon to stir for 1 minute

2 Mix dry ingredients together

Add liquidingredients Pour into

blender or use hand mixer and blend or mix 2 minutes

Add egg. Use mixer or blender to blend for 1 minute

3 Mix dry ingredientstogetherAdd liquidingredients Use whisk, stiringredients 1 minute

Add egg. Use whisk, stiringredients 2 minutes

Notebook/3-ring binder Notebook keeping (teams are encouraged to bake

goods, observe and record the differences caused by adjusting the ingredients from the Approved List of Ingredients). Optional but suggested for keeping records of all experimental data and documentation May be bound, spiral, or ring Must securely hold all items Don’t erase in lab notebook! Document all references Use pen

Notebook i. Experiment Name – 2 Points ii. Hypothesis – 4 points iii. Variables:

a. Controlled Variable(s) – 2 points b. Independent Variable(s) – 2 points c. Dependent Variable(s) – 2 points

iv. Materials (amount of each ingredient in grams or milliliters) – 4 points

v. Procedure – 10 points vi. Qualitative observations during the experiment (be

sure to include sensory score sheet) – 6 points vii. Quantitative observations during the experiment

(Data table, graphs-be sure to include nutritional calculations, viscosity testing, density, and crumb testing results) – 10 points

viii. Discussion of Results – 6 points ix. References – 2 points

Cupcake Use any combination of ingredients from the

approved list as well as physical parameter changes (temperature, cupcake lining materials, etc.) to formulate an ideal team cupcake. Teams may choose variables used in the first two experiments or use new variables. If a recipe from a cookbook or web site is used as a starting source, the source must be listed in the notebook.

Aiming for a density of 0.3 g/ml Aiming for less than 0.3% of the mass of the

cupcake to be left on liner or in crumbs when liner taken off

Must have nutrition food label

Viscotester Made from 8 oz Styrofoam cup

Heat 16 penny nail with tea candle for ~1 minute (or until it gets too hot to hold)

Punch hole from INSIDE into center bottom of cup

Place tape over hole Time how long it takes for same amount of

each standard liquid to break flow as it leaves

When determining how much fluid to use, keep a couple of items in mind

The larger the amount of fluid the less influence reaction time will have on error.

The amount of fluid the event supervisor is likely to allow the team to have.

Standard Curve Use same amount of standard fluids

to calibrate Time how long it takes to break

stream

Standard Curve

Viscosity Students need to investigate viscosity

of their batters and compare to final results.

The resistance of a fluid to deformation. Temperature dependent *Dynamic or simple viscosity Kinematic viscosity: ratio of

viscosity/density Shear viscosity – reaction to a shearing

stress (pumping, spraying, etc.) Must know general nomenclature

Measuring Density  

Density Score Sheet Students should measure the density

of each of their experimental cupcakes and record

Suggested Density Suggested Score.28-.329 5

.25-.279 or .32-.359 4

.21-.249 or .36-.389 3

.19-.209 or .319-.42 2Less than .19 or greater

than .421

Nutrition Students will create a food label for

their cupcakes properly indicating serving size, calories, amount fat, unsaturated fat, saturated fat, carbohydrates, sugars, fiber, and protein, as well as accompanying daily value percentages.

Students are NOT to be scored on how healthy the cupcake is, only on their ability to identify its role in a healthy diet.

Nutrition Calorie - amount of heat required to raise the temperature

of 1 gram of water 1 degree Celsius. Kilocalorie (1000 calories) is the unit commonly used to

represent energy values of foods -or Calorie with a C instead of a c

Not all carbohydrates (or fats, or proteins) yield the exact same amount of energy when burned in a calorimeter, so common averages from studies (in kcal/g) are used

Carbohydrates average 4.1 kcal/gram in a bomb calorimeter, are about 98% digestible and yield 4 kcal/g when consumed

Proteins average 5.7 kcal/g in a bomb calorimeter, are not as easily digested and yield an average of 4 kcal/g when consumed

Lipids average 9.5 kcal/g in a bomb calorimeter, are 95% digested and yield an average of 9 kcal/g when consumed

Fats (lipids) are the most concentrated source of food calories

Carbohydrates are the cheapest source of calories, proteins the most expensive

Fiber Foods not digested by human

digestive system Two types

Soluble Fiber-helps regulate blood sugar Found in Oats & Oat Bran, some Fruits &

vegys Insoluble Fiber-helps clean out colon

Found in whole wheat, some fruit skins and vegys

Nutritional labeling1) Fill in the following blanks.

a) There are ___ Calories/gram of fat.b) There are ___ Calories/gram of carbohydrate

c) There are ___Calories/gram of proteind) There are ___Calories/gram of water

2) Use the nutritional label given for information to answer the following questions:

a) Calculate the Calories in one serving of this product.

(1)Calories from Fat(2)Calories from Protein(3)Total Calories in one serving

b) What percent of the carbohydrate Calories come from fiber?

c) If the daily value of iron is 18 mg per day, calculate the amount (in mg) of iron in one bar of this product.

Nutrition Scoring The labels will be scored as follows:

i. Creative Cupcake name (5 points) ii. Ingredient List in correct order (15

points) iii. Nutritional Facts in correct order (15

points) iv. Package Weight (10 points) v. Company (team) Name and Address in

the correct location (5 points) vi. Label Information matches notebook

(10 points)

Sensory Score SheetAttribute Score (Circle for each attribute listed)Flavor          

Aroma 1Terrible

2 

3Average

4 5Very Pleasing

 Starch

1Raw or burned

2Under or over

cooked

3Slightly under or over cooked

4Pleasingly cooked

5Very

Pleasingly cooked

 Dairy/Milky

1Spoiled

2Moderate off-

flavor

3 Slightly off

flavor

4OK

5Pleasant

 Sweetness

1Way too much or too little

2Moderately too much or too

little

3Slightly too sweet or too

tart

4About right

5Perfect sweetness

 Vanilla

1Way too much or not enough

2Moderately too much or too

little

3Slightly too much or too

little

4About right

5Excellent

Texture           

Surface1

Really rough2

Somewhat rough3

Moderately rough

4Slightly smooth

5Smooth

 Moisture

1Dry

2Moderately dry

3Somewhat dry

4Somewhat moist

5Moisture just

right 

Cohesiveness1

Really gummy2

Somewhat gummy3

Slightly gummy4

Falls apart easily

5Just right

 Stickiness

1Really sticky

2Moderately sticky

3Somewhat sticky

4Slightly sticky

5Just right

 Circle any of the following if present

 Sour

 Bitter

 Astringent

 Gritty

Oxidized (paint) flavor

Resources For Event Supervisors

http://mypage.iu.edu/~lwoz/socrime/index.htm

For Lesson Plans for classroom use http://mypage.iu.edu/~lwoz/socrime/ind

ex.htm

Questions

Thank You

Time to Experiment We can make viscotesters We can simulate a standard curve

data collection We can find the viscosity of a batter We can find the density of muffins We can work with some tests from a

simulated test. It is your option