Food Chemistry (B) Trial Event - Science Olympiad · PDF fileFood Chemistry (B) Disclaimer ......

Linda Wozniewski

lwoz@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 visorgogsare permitted

Long-Sleeved Shirt (if wearing a lab apron)

What Students MUST Bring

Impounded

6 Cupcakes with recipe card, clean cupcake liner, and team information

Notebook with experiments

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

30% Experimental Notebook

10% Cupcakes

2% Density

2% Sensory

2% Crumbs

4% Nutritional Guidelines

60% Tasks and Experiments

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 – three mandatory

Mixing method

Ingredient chemistry

Viscotester 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 Ingredients

Liquids Lipids Leavening agents

Flours Sweeteners

Water, Whole

Milk (Cow or

Goat), Skim

Milk,

Buttermilk,

Almond Milk,

Soy Milk,

Coconut Milk,

Eggs, Egg

Substitute

Vegetable oils,

Shortening,

Butter

Margarines,

Chocolate

Baking powder

Baking soda

Cream of

tartar

FlavoringSalt

All purpose white flour

Bread flour

Cake flour

Whole wheat flour

Almond flour

Coconut flour

Corn Flour

Rice Flour

Sugar

Brown sugar

Honey

Sucralose

Aspartame

Vanilla

For State &

Nationals

Fructose

Powdered

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

FoodLauricacid

Myristcacid

Palmitcacid

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 Sweetener Liquid Egg lipid Salt Vanilla

1 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 4

1 Mix dry ingredients

together

Add liquid

ingredients

Using spoon, stir

ingredients for

30 seconds

Add egg. Use spoon to

stir for 1 minute

2 Mix dry

ingredients

together

Add liquid

ingredientsPour 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 ingredientstogether

Add liquidingredients

Use whisk, stiringredients 1 minute

Add egg. Use whisk, stiringredients 2 minutes

Notebook Notebook keeping

30% of Regional score

All experimental data and documentation must be recorded in notebook

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 2

Less than .19 or greater than .42

1

Crumbs

Crumb Scoring

Students should score how much of their cupcakes stick to the paper or crumb for each of their experimental cupcakes

Percent of Crumbs Suggested Score

Less than .3% 5

.31-.4% 4

.41-.5% 3

.51-.6% 2

.61-.7% 1

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 labeling

1) 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 protein

d) 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 1

Terrible

2 3

Average

4 5

Very Pleasing

Starch

1

Raw or burned

2

Under or over

cooked

3

Slightly under or

over cooked

4

Pleasingly cooked

5

Very Pleasingly

cooked

Dairy/Milky

1

Spoiled

2

Moderate off-flavor

3

Slightly off flavor

4

OK

5

Pleasant

Sweetness

1

Way too much or

too little

2

Moderately too

much or too little

3

Slightly too sweet

or too tart

4

About right

5

Perfect sweetness

Vanilla

1

Way too much or

not enough

2

Moderately too

much or too little

3

Slightly too much

or too little

4

About right

5

Excellent

Texture

Surface

1

Really rough

2

Somewhat rough

3

Moderately rough

4

Slightly smooth

5

Smooth

Moisture

1

Dry

2

Moderately dry

3

Somewhat dry

4

Somewhat moist

5

Moisture just right

Cohesiveness

1

Really gummy

2

Somewhat gummy

3

Slightly gummy

4

Falls apart easily

5

Just right

Stickiness

1

Really sticky

2

Moderately sticky

3

Somewhat sticky

4

Slightly sticky

5

Just right

Circle any of the

following if

present

Sour Bitter Astringent Gritty

Oxidized (paint)

flavor

State and Nationals Icing – emulsion mixture of two or more

immiscible (un-blendable) liquids

Basic Recipe

2 cups confectioners' sugar, sift before measuring-or sugar substitute

1 1/2 tablespoons butter, soft or butter substitute

1/2 teaspoon vanilla extract

1/4 teaspoon salt

3 to 4 tablespoons milk or milk substitute

Combine all icing ingredients in small mixing bowl. Stir until smooth and well blended. Adjust for spreading consistency if necessary, adding more milk or more confectioners' sugar.

Advanced Experiments

Document at least 4 additional experiments in the laboratory notebook involving the icing

Experiments should include varying the ingredients as well as the quantities of the ingredients.

Researchers will need to document how easily the icing spreads, how well it holds its shape, and how long it takes to dry out as well as evaluating the sensory experience

Resources

For Event Supervisors

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

For Lesson Plans for classroom use

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

Questions

Thank You

Time to Play

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 (substitute cupcakes)

We can work with some tests from a simulated test.

It is your option