1. Which component makes up the largest percentage of whole cow’s milk by mass?
- A.A) Fat
- B.B) Protein
- C.C) Lactose
- D.D) Water
Food Science Practice Test — Easy Level
A free 10-question Food Science practice test for Science Olympiad, written at invitational level. Every question and answer choice is listed below — correct answers and scoring are revealed when you take the timed test.
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2. In cow’s milk, which carbohydrate is present in the highest amount and is specifically broken down by the enzyme lactase?
- A.A) Sucrose
- B.B) Lactose
- C.C) Glucose
- D.D) Maltose
3. A student adds vinegar to warm milk until curds form and then drains off the liquid. What is the proper name for the remaining liquid after the casein curds are removed?
- A.A) Whey
- B.B) Cream
- C.C) Serum
- D.D) Buttermilk
4. Which statement correctly compares saturated and unsaturated fatty acids in milk fat?
- A.A) Saturated fatty acids contain at least one C=C double bond and are usually liquid at room temperature.
- B.B) Saturated fatty acids have no C=C double bonds and tend to be solid at room temperature.
- C.C) Unsaturated fatty acids have no C=C double bonds and are always solid at room temperature.
- D.D) Unsaturated fatty acids have no effect on the physical state of milk fat at room temperature.
5. Which major protein fraction in milk forms micelles that clump together to make curds when the pH is lowered to about 4.6?
- A.A) Whey proteins
- B.B) Collagen
- C.C) Casein
- D.D) Gluten
6. During yogurt production, lactic acid bacteria ferment lactose. Which change in the milk directly causes yogurt to become thick and tangy?
- A.A) Increase in pH, which dissolves casein micelles
- B.B) Decrease in pH toward 4.6, which causes casein to gel
- C.C) Increase in temperature above 80 °C, which melts casein micelles
- D.D) Decrease in lactose concentration, which crystallizes and thickens the product
7. Which best describes milk from a physical-chemistry viewpoint?
- A.A) A pure compound consisting only of water
- B.B) A simple solution of fat and protein in water
- C.C) A true solution, a colloidal dispersion, and an emulsion all at once
- D.D) A suspension of ice crystals and air cells in water
8. A student with LACTOSE INTOLERANCE drinks a glass of regular cow’s milk and later experiences gas and cramps. Which is the primary cause of these symptoms?
- A.A) Immune reaction to casein proteins
- B.B) Deficiency of the enzyme needed to digest lactose
- C.C) Sensitivity to added vitamin D in fortified milk
- D.D) Inability to digest milk fat due to missing lipase
9. Milk is homogenized before or during processing. What is the main purpose of homogenization?
- A.A) To kill pathogenic bacteria in milk
- B.B) To break fat globules into smaller ones so cream does not separate
- C.C) To remove lactose and make milk safe for lactose-intolerant consumers
- D.D) To evaporate water so milk becomes shelf-stable at room temperature
10. An ice cream mix has a freezing point of about -1.0 °C due to dissolved sugars. If the ice-salt brine around the bag reaches -5.0 °C, which statement best explains why this helps the ice cream freeze smoothly?
- A.A) The brine is colder than the mix’s freezing point, so heat flows out and many small ice crystals form.
- B.B) The brine is warmer than the mix’s freezing point, so it slowly melts any ice that forms.
- C.C) The brine has the same freezing point as the mix, so only a few large ice crystals form.
- D.D) The brine’s temperature does not affect crystal size; only air mixing matters.