Food Science

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The Event

The event (2017-2018) consisted of a written test and a lab portion where students must use a homemade calorimeter. The competition often required competitors to run chemical detection tests such as Benedict's test or a Biuret test. The event (2019-2020) is focused on fermentation and pickling. It consists of a lab portion, where you can have anywhere from 1 to all of the following labs: using a student-made salinometer to find the salt content (0-10%) of an unknown solution, find the pH of a pickle, and find the water content of a pickle. To be allowed to participate, you must bring:

  • ANSI Z87 goggles (eye protection #4)
  • Closed-toe shoes (no sandals)
  • Plastic bags,cups, and spoons
  • Graduated cylinders and beakers
  • pH paper
  • A homemade salinometer

Types of Fermented Foods


  • Bread is made from flour through alcoholic fermentation.
  • Cheese is made from milk through alcoholic fermentation.
  • Kimichi is made from Korean cabbage through lactic acid fermentation.
  • Kombucha is made from tea through alcoholic fermentation.
  • Sauerkraut is made from cabbage through lactic acid fermentation.
  • Yogurt is made from milk through lactic acid fermentation.

Types of Cellular Respiration

Aerobic Respiration

Aerobic means "involving oxygen." Therefore, it can be concluded that aerobic respiration is a process involving oxygen, consisting of three metabolic processes to create ATP from glucose. In order, these process are glycolysis, the Krebs cycle (also known as the tricarboxylic acid cycle (TCA) or the citric acid cycle), and the electron transport chain + chemiosmosis, also known as oxidative phosphorylation.

Aerobic respiration occurs in the mitochondria of eukaryotic cells (our own human cells!). Its final electron acceptor is oxygen and produces water and carbon dioxide as byproducts. Theoretically, 36-38 ATP is produced in this process, a lot more than in anaerobic respiration, the reason that this process is the preferred pathway when oxygen is available.

It is represented by the following chemical equation.

1====Glycolysis==== Glycolysis is a metabolic pathway of both aerobic and anaerobic respiration. There are multiple types of glycolysis, but the Embden–Meyerhof–Parnas (EMP) pathway is the one most focused on in Food Science. It can occur in conditions with or without oxygen and occurs in the cytosol of living cells.

Its purpose is to extract energy from glucose by converting it into pyruvate, a three-carbon molecule. Technically, this process produces 4 ATP, but because two are needed for the preparatory phase, one of the two phases of this process, only 2 net ATP are produced. During this process, [math]\mathrm{NAD^+}[/math] is also reduced (gains electrons) and converted into NADH. [math]\mathrm{Mg^2+}[/math] is used as a cofactor in steps involving glucose and substrate-level phosphorylation, but [math]\mathrm{Mn^2+}[/math] can also be used.

The chain of reactions that make up this pathway are:

This process can be separated into ten steps. Each step is described below.

Phase I

Step 1: Glucose is converted into glucose 6-phosphate through the addition of a phosphate group taken from ATP and is catalyzed by the enzyme hexokinase. To keep the glucose concentration from getting too high and leaving the transport, 1 molecule of ATP is utilized for this step and converted into ADP. This step is also known as the phosphorylation of glucose.

Step 2: Glucose 6-phosphate can then be converted into fructose 6-phosphate, an isomer of glucose-6-phosphate through the rearrangement of its atoms. The enzyme phosphoglucose isomerase is used and required to carry this reaction out. This reaction is also reversible under the condition that there is a high concentration of fructose 6-phosphate, which is often not the case, so therefore most of the time this reaction is in the forward direction.

Step 3: The end product of step 2, fructose 6-phosphate is converted into fructose 1, 6-biphosphate, also known as the phosphorylation of fructose 6-phosphate. Once again, a phosphate group used from an ATP molecule is added to fructose 6-phosphate in order to make this reaction occur, converting ATP to ADP also once again. The enzyme used to catalyze this reaction is phosphofructokinase, an enzyme which is limited where ADP concentrations are low, and vice versa.

Step 4: Fructose 1, 6-biphosphate further continues in this pathway and is split into two isomers, glyceraldehyde-3-phosphate, an aldose, and dihydroxyacetone phosphate, a ketose. The enzyme fructose diphosphate aldolase is used for this step.

Step 5: After step 4, only dihydroxyacetone phosphate continues on to step 5, which is then converted into the same molecule as the other molecule product of step 4, glyceraldehyde-3-phosphate, catalyzed by the enzyme triosephosphate isomerase, and thus concluding the first phase of glycolysis.

Phase II

Step 6: Unlike ATP, where something was taken away from it, [math]\mathrm{NAD^+}[/math] is converted to two molecules of NADH through the addition of electrons, which used from glyceraldehyde-3-phosphate, converting glyceraldehyde-3-phosphate to producing 1,3-bisphosphoglycerate after the addition of another phosphate group included, but not from an ATP molecule. This reaction is catalyzed by the enzyme glyceraldehyde 3-phosphate dehydrogenase. However, NADH must be oxidized and converted back into [math]\mathrm{NAD^+}[/math] again and again in order for glycolysis to continue, which can be done in conditions with oxygen. Fermentation can be used as a pathway to do so if oxygen is not available. The end product of this pathway is NADH though, and not [math]\mathrm{NAD^+}[/math].

Step 7: A high-energy phosphate group is transferred from 1,3-bisphosphoglycerate to ADP, catalyzed by the enzyme phosphoglycerate kinase and forming 3-phosphoglycerate and ATP, respectively. This process of a transfer of a phosphate group to ADP from another molecule is also known as substrate-level phosphorylation, which also occurs in the last step.

Step 8: This reaction is catalyzed by the enzyme phosphoglycerate mutase. It occurs during the movement of the phosphate group in 3-phosphoglycerate from the third carbon atom to the second carbon atom, forming 2-phosphoglycerate, which is an isomer of 3-phosphoglycerate.

Step 9: 2-phosphoglycerate is dehydrated in this second to last step, losing two moles of water in the process and is converted into phosphoenolpyruvate. The enzyme enolase (aka phosphopyruvate hydratase) helps by catalyzing this reaction.

Step 10: Once again, as stated in step 7, a phosphate group is transferred from phosphoenolpyruvate (aka PEP) to an ADP molecule, forming another ATP molecule and converting PEP to pyruvate, marking the last step of glycolysis. The enzyme pyruvate kinase is used to catalyze this reaction and is required for cellular respiration to continue on.


Since we're talking about aerobic cellular respiration here, pyruvate is first converted to Acetyl-CoA and then continues on with the Krebs cycle and the rest of the cellular respiration. If a cell fails to reach the aftermath of glycolysis, it will die. However, in anaerobic cellular respiration, fermentation can be used as an alternate pathway since there isn't any oxygen involved in the process of anaerobic respiration.

Krebs Cycle

Electron Transport Chain


Anaerobic Respiration



Types of Fermentation

Alcohol Fermentation

Lactic Acid Fermentation (Heterolactic)

Lactic Acid Fermentation (Homolactic)

Food Preservation









A triglyceride


Saturated Fatty Acids


Unsaturated Fatty Acids


Omega-3 Essential Fatty Acids


Trans Fats





Esters are found on the end of all fatty acids.



Common esters include ethyl acetate and ethyl ethanoate.



Sterol.png (picture credit Wikipedia)






Simple Sugars


  • Glucose (also dextrose)
  • Fructose (also levulose)
  • Galactose
  • Mannose

Common disaccharides include:

  • Sucrose (glucose+fructose)
  • Lactose (glucose+galactose)


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

Complex Sugars



Storage Polysaccharides


  • Glycogen is the storage polysaccharide found in animals.



Structure Polysaccharides

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





Protein Denaturation and Coagulation





Amino Acids


Complete and Incomplete Proteins







Food Testing




Making a Calorimeter


  1. Measure the water in the small can and record.
  3. Measure the temperature of the water and record.
  7. Using these measurements, fill out the equation.

Calorimeter Equation


  • Q is total heat generated by food (calories)
  • Substitute all of the measurements that you took before.
    • Make sure to have all of the units!
    • This leaves calories as the unit for Q.


    • 1 calorie/gram = 4.1868 joules/gram.

Molecule Detection Tests




To use Benedict's:

  3. Add 5-10 drops of Benedict's Solution.

To deduce the results:





To use Biuret's:

  3. Add 2-5 drops of Biuret's Solution.
  4. Swirl gently to mix.
  5. Let sit for five minutes.

To deduce the results:


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 the formation of polyiodide chains from the reactive starch and iodine.

To use Iodine:

  3. Add 2-5 drops of Iodine.
  4. Swirl gently to mix.

To deduce results:

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

Brown Bag


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. Foods containing more lipids will stain the bag more transparently than ones that have fewer lipids.





Competition Tips

  1. Study a lot. This event is one of the heaviest in terms of what teams need to know, therefore retention is crucial.


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