Linda Wozniewski lwoz@iun.edu Food Chemistry (B) Linda Wozniewski lwoz@iun.edu

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 All skin from neck to toes covered Lab coat or lab apron Indirect vent or unvented chemical splash proof goggles. All skin from neck to wrists covered Long hair (shoulder length or longer) must be tied back. Visorgogs now permitted

What Students MUST Bring Safety gear Cheesecloth pH paper Writing implement Paper towels Laboratory notebook – impounded Graduated cylinders Beakers Spoons Equipment to do activities Cups 500-600 ml plastic bottle with lid Plastic bags

What Supervisors Will Supply Dairy products Balance Thermometers Everything the student will need Lemon juice or vinegar if doing cottage cheese Ice, salt, and sugar if doing ice cream Anything else that may be needed if any other tests are to be done.

What Students May Bring Graphing Calculator 5 sheets of paper (both sides) on which anything is acceptable

Main Focus Chemistry of Food How to prepare students Experiment ideas 20% Laboratory Notebook 40% Competition task 40% Written test How to prepare students Experiment ideas Resources

Chemistry of Food Identify the sources of and understand the role of lipids, carbohydrates and proteins typically found in foods, and use tests to identify these compounds, including the Benedict’s, Iodine and Brown Bag tests. When given samples of sweeteners, use the Benedict’s test to identify reducing sugars. When given samples of ingredients, use the Biuret test to identify and rank the ingredients by protein content. Use standard labeling regulations to produce a label from information given. Organic reactions such as esterification, fermentation, pickling, fat bonding Identify leavening agents using chemical tests Saturated and unsaturated fats Chemical structure of sugars, starches, fats, and proteins Essential fats, vitamins, protiens

Chemistry of food, con’t. How cooking changes food chemically Allergens in foods Food preservation RDA (recommended daily allowance) of essential minerals and vitamins and the consequences of not having them

Before your event Research! Understand the science first Experiment: How does the pH (how much acid should you add) of the milk effect the production of cottage cheese? How does the temperature of the cream effect the percentage of fat? How does the percentage of fat in the milk effect how high a tower you can make? How does the amount of time you leave the ice cream in the ice effect the height of the tower?

Ingredients The right ingredients Liquids…. Lipids Sweeteners Must understand WHY you are using the ingredient…what function does it provide?

Carbohydrates Carbohydrates Basic unit – monosaccharide 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 Reducing sugars Monosaccharides Examples: glucose, lactose, fructose Non-reducing sugar contains no hemiacetal groups. Example: sucrose Sugars Monosaccharides Glucose, Fructose Disaccharides Lactose (glucose and galactose) -milk Maltose (glucose and glucose) - Sucrose (glucose and fructose –table sugar

Carbohydrates Polysaccharides Examples: Branched vs. linear 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

Fiber Non-starch polysaccharides (cellulose, etc.) Food 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. Cellulose

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 11% 29% 13% Dark chocolate 0% 34% 43% Eggs 0.3% 27% 10% Soybean oil 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 Proteins are made up of long intricate folded chains of amino acids Protein can be found in the flour, egg and milk as well as other ingredients. When foods cook, the proteins denature

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

Notebook Notebook keeping 20% of score All experimental data and documentation must be recorded in notebook We are using a standard page Document all references Use pen Provide Pictures of product/experiment Pages are available on-line

Experiment Form- Include picture of product/experiment on back of page Food Science B-Dairy Experiment Form- Include picture of product/experiment on back of page   Team ___________________________________ Date _________________________ Team Members ______________________________ _________________________ Product to be made: ______________________________________________________________ Independent Variable: _____________________________________________________________ Dependent Variable:_______________________________________________________________ Controls: ______________________________________________________________________ _______________________________________________________________________ Results: _______________________________________________________________________ Analysis: ______________________________________________________________________ ______________________________________________________________________

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

Nutritional labeling Fill in the following blanks. There are ___ Calories/gram of fat. There are ___ Calories/gram of carbohydrate There are ___Calories/gram of protein There are ___Calories/gram of water Use the nutritional label given for information to answer the following questions: Calculate the Calories in one serving of this product. Calories from Fat Calories from Protein Total Calories in one serving What percent of the carbohydrate Calories come from fiber? If the daily value of iron is 18 mg per day, calculate the amount (in mg) of iron in one bar of this product.

Resources For Event Supervisors For Lesson Plans for classroom use http://mypage.iu.edu/~lwoz/socrime/index.htm For Lesson Plans for classroom use

Questions Thank You

Time to Play We will make: Ice Cream Cottage Cheese Butter

Ice Cream Milk should be cold, so we will do this first The milk has already been measured out to 125 ml The sugar has already been measured out to 15 ml (1 tablespoon) Add the milk and sugar to the pint plastic bag and manipulate to dissolve the sugar The salt has already been measured out to 90 ml (120 g) Fill the gallon plastic bag ½ full of ice & add salt

Ice Cream con’t Mix the ice and salt Add the bag of milk and sugar Agitate for 15 minutes. (Switch off people agitating) Pour out the ice cream into a plastic cup or beaker and see how high a tower you can make

Butter The 150 ml of heavy cream has already been measured out. Find the mass of the cream Add this to the 500 ml water bottle The temperature should be about 13 ºC Put on the cover and shake horizontally vigorously for about 15 minutes The contents will become solid and then liquid again Pour off the liquid

(Mass of fat/mass of cream)*100 Butter continued Pour of all liquid and rinse with cold water (someone will have to go to the bathroom to do this I am afraid) Put the butter in a beaker and work until the liquid is out Find the mass of the butter Calculate the % of fat (Mass of fat/mass of cream)*100

Cottage Cheese 150 ml of milk has already been measured out. Find the mass of the milk The milk needs to be about room temperature Add ~6 ml of vinegar, 1 drop at a time Swirl gently or mix gently Allow to sit for five minutes Put a piece of cheese cloth over a beaker and secure it with a rubber band. It is best if the cheese cloth is not taught

Cottage Cheese Pour the cottage cheese curds into the cheese cloth After 15 minutes gather up the cheese cloth and gently squeeze to remove the rest of the whey Spread the cheese cloth out to dry Determine the mass of the casein Determine the % curds.