Food Science

Food Science is a debut event focusing in on chemical and physical knowledge of baking ingredients and lab testing, such as viscosity. Food Science was a trial event in states such as Texas and North Carolina for quite a while. When it is run in Texas as a trial, it differs from many other states.

The Event
This event consists of doing some lab testing, and some written testing. It requires a viscosity station, plus seven other stations relating to foods in the rules. This makes for 8 stations. The rules say that you may have even more than this.

To be allowed to participate, you must bring:  ANSI Z87 goggles (eye protection #4) Lab coats or lab aprons that reach the knees. If you are using lab aprons, your sleeves must reach your wrists. Closed toe shoes(no sandals) Pants or skirts that cover the legs to the ankles 

You may also and should bring:  Chemical gloves(you can't touch chemicals and foods in the lab 1 three-ring binder of any size, containing notes in any form from any source Homemade viscotester (calibrated and graphed)</li> </ul>

Macromolecules
Macromolecules are very large molecules. They are conventionally four different biopolymers: Lipids, carbohydrates, proteins, and nucleic acids. The last does not apply to Food Science therefore we only need to pay attention to the first three. In each of these categories of macromolecules, some subcategories exist.

Lipids
Lipids have many subcategories, such as fats, waxes, and sterols. The main ones you need to worry about are the triglycerides- fats and oils.

Fats
Fats are a good source of energy, giving 9 kcal/g of fat. The daily recommended amount of fat intake is limited to 65g.

Fats are most commonly found as triglycerides. Triglycerides are made up of a glycerol backbone with three fatty acids attached. Fatty acids are long chains of carbon molecules with an ester group on the end. The fatty acids may be saturated, unsaturated, or trans. Triglycerides can use any combination of these different fatty acids.

Saturated Fatty Acids
Saturated fatty acids are one long chain of carbon atoms, no double bonds, no fancy stuff. Saturated fats are generally bad for you since they clog your arteries, increasing the risk of heart attack and stroke. Since the carbon atoms in a saturated fatty acid are pack closely together, saturated fats are usually solid at room temperature. Saturated fats are generally found in animals.

Unsaturated Fatty Acids
Unsaturated fatty acids are also a long chain of carbon atoms, this time with one or more double bonds. Unsaturated fatty acids with one double bond are monounsaturated, and those with two or more double bonds are polyunsaturated. Unsaturated fats are generally better for you when not overeaten because they may help lower blood cholesterol level. Since double bonds exist, these fatty acids are much more wobbly and therefore are usually liquid at room temperature. Unsaturated fats are generally found in plants such as nuts and seeds. They are also found in fish as omega-3 unsaturated fatty acids.

Omega-3 Essential Fatty Acids
Omega-3 essential fatty acids are found in fish and in plants. The name means there exists a double bond three carbon atoms from the non-ester end of the chain. (Omega is the last letter in the Greek alphabet.) These fatty acids are "essential" because your body cannot produce them and they are vital for normal metabolism.

Trans Fats
Trans fats are not found in nature, although recent studies show that there may be small amounts. Trans fats are unsaturated fatty acids heated up, then made so "dizzy" that cis bonds flip over into trans bonds. Trans fats are unhealthy for you since they lower HDL (good cholesterol) and raise LDL (bad cholesterol). The recommended daily intake should be limited to 2g per day.

Sterols
The one sterol you'll want to know about is cholesterol. Cholesterol, like all sterols, come in this form:

(picture credit Wikipedia)

Cholesterol comes in LDL, "bad" cholesterol, and HDL, "good cholesterol". HDL is made by your liver, while LDL is generally consumed. Some types of foods, such as trans fats, are thought to raise LDL and lower HDL.

If you have too much LDL, your heart arteries will clog and as a result, you will get a heart attack. This is cardiovascular disease, the leading cause of death in America.

Carbohydrates
Carbohydrates, are, as implied, hydrates of carbon. They consist of carbon, oxygen, and hydrogen atoms. The formula for a carbohydrate can be expressed as $$C_m(H_2 O)_n$$, where most commonly $$m$$ and $$n$$ are the same.

Carbohydrates consist of simple sugars, monosaccharides and disaccharides, and complex sugars, polysaccharides.

Simple Sugars
Simple sugars consist of single sugar units, monosaccharides, and disaccharides, which are made up of monosaccharides. Common monosaccharides include:  Glucose(also dextrose)</li> Fructose(also levulose)</li> Galactose</li> Mannose</li> </ul>

Common disaccharides include:  Sucrose(glucose+fructose)</li> Lactose(glucose+galactose)</li> Maltose(only found as a byproduct of hydrolysis of starch)(glucose+glucose)</li> </ul>

Simple sugars are small and easy to break down, therefore give you energy quite soon after you consume simple sugars, but run out quickly, leaving you tired.

The "Sugars" on food label consist of mono- and di-saccharides. That's why you see sugar in milk; that's lactose, not added by the manufacturer.

Complex Sugars
Complex sugars are mainly polysaccharides. Polysaccharides are chains of many, many monosaccharides, most commonly glucose.

Polysaccharides are divided into two main groups, storage polysaccharides and structure polysaccharides.

Storage Polysaccharides
Storage polysaccharides are our main sources of energy. There are two main storage polysaccharides: glycogen and starch.

Glycogen is the storage polysaccharide found in animals.

Starch is the storage polysaccharide found in plants. We humans consume a lot of it, such as in pasta or potatoes.

Starch comes in two forms: amylose and amylopectin. Amylose is a straight chain of glucose molecules which coils up. Amylopectin is branched. Since there are more ends to be broken down in amylopectin, amylopectin is more quickly digested.

When you look at a food label, the Dietary Fiber and Sugars don't quite add up to the Total Carbohydrate; the remainder is starch.

Structure Polysaccharides
Structure polysaccharides are polysaccharides meant to give structure. Two common structure polysaccharides are celluose and chitin.

Celluose is better known as dietary fiber. It is insoluble, meaning indigestible by our bodies, so it cleans out our insides and comes out as feces.

Proteins
Proteins are polymers of amino acids. Proteins are essential to human life because it carries out orders from the genes in cells.

Proteins can be converted to energy by the liver when there is a lack of carbohydrate or fat, therefore provides 4 C/g.

Protein Denaturation and Coagulation- Denaturation is the undoing of natural structure by chemical or physical means. It doesn’t do anything to the composition, only the structure. Protein denaturation can happen because of heat (140- 180 degrees Fahrenheit/ 60- 80 degrees Celcius), high acidity, air bubbles, or any combination of the three. Since denaturation undos the folds of the proteins, there are more open bonds, so they form new bonds. This creates a thickness or density. Coagulation is when the new bonds are formed.

A form of proteins is enzymes.

Enzymes
Enzymes are special proteins that catalyze chemical reactions. The names of enzymes often end in -ase. Examples are maltase(breaks down maltose), amylase(breaks down amylose and amylopectin), and lactase(breaks down lactose).

Some enzymes cause disease due to the fact that some people do not contain them, or possess distorted, non-functional forms. The most common disease is phenylketonuria, a lack of functional phenylalanine hydroxylase, an enzyme. When functional, phenylalanine hydroxylase is supposed to break down phenylalanine, an amino acids found in the artificial sugar aspartame.

Amino Acids
Amino Acids are the building blocks of proteins. There are 20 "essential" amino acids. Amino Acids consist of 10-40 atoms each, mainly carbon, hydrogen, a couple sulfur, and at least one nitrogen in amine group- NH2. Proteins are formed by linking the amine nitrogen with a carbon atom on another amino acid, forming a peptide bond.

Food Testing
At the competition, you are expected to know how to perform certain experiments on certain foods. Most tests will instruct you on use, but know how to perform them anyway.

Viscosity
Viscosity is the main testing subject of Food Science in 2011-2012. It is mandatory, so you *may* yell at your event supervisor if (s)he does not have this station. You will need to make your own homemade viscotester and graph it.

Vocabulary
Viscosity-the resistance of fluid to flow

Centipoise-a measure of viscosity. Often abbreviated cP. $$\frac{1}{100}^\text{th}$$ of a poise.

To make a viscotester, here are the instructions as proposed by the rules:

"The viscosity-testing device can be made from an 8 oz. Styrofoam cup by heating the end of a 16 penny nail (hold it with an insulated glove or a pliers) over a candle approximately one minute and then punching a hole from INSIDE the cup into the center bottom of the cup. Place tape of the hole. For each test, fill the testing device with the same amount of each liquid to be tested. After removing the tape, time how long it takes for the liquid to break the flow as it leaves the cup. Record your data to create your standard curve graph(s)."

As said above by the rules, you must use the same amount of liquid for each test. If you do not use the same amount each time, your graph will be wrong and you will not be able to accurately predict centipoise.

The six liquids suggested by the rules to calibrate your device are:

Water-1 cP

Mazola Canola Oil-60 cP

Hershey's Chocolate Syrup-1000 cP

Karo Corn Syrup-2000 cP

Molasses-3000 cP

Pure Honey-6000 cP

Be sure these liquids are all fresh and at room temperature when you start testing.

Now you create your standard curve graph with Excel(or a similar program). You should be able to now predict the mystery liquids' viscosity at the competition!

Do not forget to hand a copy of your graph to the judge with your test.

Molecule Detection Tests
There are certain tests used to detect macromolecules and other molecules in food. You may have to perform some of these at the competition. The most common tests that you are expected to perform are Benedict's, Biuret's, Iodine, and the Brown Bag test. You may also need to know about Sudan III/IV and Vitamin C Reagent(dichlorophenolindophenol).

Benedict's
Benedict's solution is also known as Fehling's solution. It tests for reducing sugars, or a sugar with a free aldehyde. The reaction between a reducing sugar and Benedict's is between the reducing sugar's aldehyde and the copper sulfate in Benedict's.

To use Benedict's: <ol> Put a small sample of the food into a test tube. Liquidify the food by adding enough water to make it a liquid, if the food is not already a liquid.</li> Add 5-10 drops of Benedict's Solution.</li> Carefully heat the test tubes in a hot water bath at $$40-50^\circ$$ Celsius for five minutes.</li> </ol>

To deduce the results:

The liquid will turn green, yellow, or brick red depending on the amount of sugar present. Green is the least sugar, yellow is more, while red is the most.

Note that Benedict's will only work with reducing sugars.

Reducing sugars are sugars with free aldehydes. (An aldehyde group is of the form R-CH=O where R is something organic.)

Here's a rule of thumb: All monosaccharides are reducing sugars but not all reducing sugars are monosaccharides. Lactose, for example, is reducing, however, sucrose is not.

Remember that Benedict's needs heating to work when answering test questions about it!

Biuret's
Biuret's Reagent is for detecting the presence of proteins. The active agent in Biuret's is also copper sulfate. The reaction is due to the formation of complex between the cupric ions in copper sulfate and the lone pair of electrons present on the nitrogen and oxygen atoms of peptide bonds of proteins.

To use Biuret's: <ol> Put a small sample of the food into a test tube. Liquidify the food by adding enough water to make it a liquid, if the food is not already a liquid.</li> Add 2-5 drops of Biuret's Solution.</li> <li>Swirl gently to mix.</li> <li>Let sit for five minutes.</li> </ol>

To deduce the results:

Biuret's will turn a pink/purple in the presence of proteins.

Iodine
Iodine solution, also Lugol's Iodine, is used to detect starch. It is a mix of the element iodine and potassium iodide. The reaction is the result of formation of polyiodide chains from the reactive starch and iodine.

To use Iodine: <ol> <li>Put a small sample of the food into a test tube. <li>Liquidify the food by adding enough water to make it a liquid, if the food is not already a liquid.</li> <li>Add 2-5 drops of Iodine.</li> <li>Swirl gently to mix.</li> </ol>

To deduce results:

The solution will turn dark blue, almost black in the presence of starch.

Note that amylose (straight chain form of starch) will stain less than amylopectin (branched form of starch).

Brown Bag
The brown bag is the easiest, least formal test. The brown bag test tests for lipids(fats).

To perform this test, spread, rub, or pour some of the food on a brown bag. Wipe away the excess, and hold the bag to the light. More fatty foods will stain more transparent than ones that have less lipids.

This test can also be done with plain paper, though the paper has to dry before it can be analyzed.

Density
You may have to find the density of certain foods, such as bread. To do this, you will have to first cut it into a uniform cuboid(a 3-D rectangle). Next, use a ruler to measure the height, length, and breadth of the object. Record these measurements. Now weigh the object. (The event supervisor should provide a scale.) Use the density formula to find the density of the food. Make sure to give you answer in the units wanted. The most common units wanted is $$\frac{g}{cm^3}$$.

The density formula is $$\text{Density}=\frac{\text{weight}}{\text{height}\cdot\text{length}\cdot \text{breadth}}$$

Competition Tips
<ol> <li>Study a lot. This event is one of heaviest in terms of what you need to know, and in terms of what is specified that you need to know, so learn a lot and keep it in your brain!</li> <li>Ask the event supervisor if you can unstaple and then later re-staple your test. This event will be a crunch on time, so this strategy may help so you can split the work with your partner.</li> <li>Get a lot of rest before the competition! Self-explanatory.</li> </ol>