Test your basic knowledge |

Food Chemistry

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
Lamellar; Hexagonal I - II; Cubic
They act as catalysts - speeding the polymerization of acrylamide.
Browning of freshly cut surfaces of fruits and vegetables.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

2. Name a naturally occurring protein sweetener.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Emulsification
Thamautin
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

3. What are the four basic flavors perceived by the tongue?
Four
Acetoin
Sweet - Salty - Sour - and Bitter
Emulsification

4. What are two common reducing agents that break disulfide bonds in proteins?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Racemic Mixture
Primary butyric acid also caproic acid.
Phenylketonuria

5. What toxic pigment is found in cottonseed endosperm?
pH 3-5
Bitter
Gossypol (it is removed during the oil refining process)
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

6. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Primary-amino acid sequence. Secondary-alpha-helix - beta sheet. Tertiary-one complete protein chain with cross bonds linking it together. Quaternary-four separate protein chains assembled as one.
Chitin
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Carmelization and Maillard

7. What does the saponification value measure and how is it measured?
Phenylketonuria
Anomeric
Blue pigment in flowers
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

8. What does Acid Degree Value measure and how is it measured?
Initiation - Propagation - Termination
Emulsoids
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Anthocyanins

9. What is the enzyme that softens tomatoes?
Degradation of protein and production of acid from sugar at the same time.
HLB (hydrophilic-lipophilic balance); a low value (3-6) promotes water in oil emulsions and a high value (8-18) promotes oil in water emulsions.
1 - 3 - 7-trimethylxanthine
Pectin Esterase

10. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Tryptophan
Four
.05
Pectins

11. What effect would the addition of sodium bicarbonate have to chocolate?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Onions ( or leeks)
Egg white proteins - the globin part of hemoglobin - bovine serum albumin - gelatin - whey proteins - casein micelles - B-casein - wheat proteins - soy proteins - and some protein hydrolyzates.
Lamellar; Hexagonal I - II; Cubic

12. Name 5 proteins with good foaming properties.
Egg white proteins - the globin part of hemoglobin - bovine serum albumin - gelatin - whey proteins - casein micelles - B-casein - wheat proteins - soy proteins - and some protein hydrolyzates.
14
Sweet - Salty - Sour - and Bitter
Lysine - Arginine - and Histidine

13. Does kosmotrophil ion discourage water structure?
Lysine - Arginine - and Histidine
Water
HPLC has higher pressure than FPLC
No

14. Which two amino acids is the aspartame derived from?
Non-protein nitrogen
Orange Juice
Yellow
Aspartic Acid and Phenylalanine

15. At what pH is benzoic acid most effective?
14
pH 3-5
Primary butyric acid also caproic acid.
Covalent (strongest) and Hydrophobic (Weakest)

16. How do sodium chloride and sucrose affect foam stability?
Tryptophan
Sodium chloride reduces foam stability and sucrose improves foam stability.
Degradation of protein and production of acid from sugar at the same time.
Sweet - Salty - Sour - and Bitter

17. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Thickener in foods
Primary-amino acid sequence. Secondary-alpha-helix - beta sheet. Tertiary-one complete protein chain with cross bonds linking it together. Quaternary-four separate protein chains assembled as one.
Tryptophan
Osmosis

18. What two common compounds are used together as an antioxidative system?
Browning of freshly cut surfaces of fruits and vegetables.
.05
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Ascorbic Acid and Citric Acid

19. What is a polymorphism?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Acetoin
pH 3-5

20. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
14
Bitter
Daminozide
Daminozide

21. What is the enzyme responsible for browning in apples and lettuce?
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Tryptophan
Polyphenol Oxidase

22. Name 3 physical agents capable of denaturing proteins.
Pheophytin forms
Anomeric
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Racemic Mixture

23. What are the four basic flavors perceived by the tongue?
Pectins
Sweet - Salty - Sour - and Bitter
14
1 - 3 - 7-trimethylxanthine

24. At low water activity What is the main deteriorative concern?
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Lipid oxidation
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
1 - 3 - 7-trimethylxanthine

25. What does Reichert-Meissert Number measure?
Bitter
Troponins and Tropomyosin
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Primary butyric acid also caproic acid.

26. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Polyphenoloxidase
Blue pigment in flowers
HLB (hydrophilic-lipophilic balance); a low value (3-6) promotes water in oil emulsions and a high value (8-18) promotes oil in water emulsions.
Covalent (strongest) and Hydrophobic (Weakest)

27. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Capsaicin
Yellow
Pectins
Water

28. What pigment was first designated as anthocyanins?
Pectin methyl esterase or galacturonase
D: None of the above
Linoleic Acid
Blue pigment in flowers

29. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Orange Juice
No
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

30. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Pectin methyl esterase or galacturonase
Pectins
Sodium chloride reduces foam stability and sucrose improves foam stability.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

31. What is surimi?
pH below positive charge; pH at no charge; pH above negative charge
A concentrate of microfibrillar proteins of fish muscle.
Blue pigment in flowers
Pheophytia does not have magnesium in porphyrin ring.

32. Are sorbitol and mannitol sweet?
Polyphenol Oxidase
Sucrose
Speed of Light
Yes

33. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Oil in Water
Lipase
A concentrate of microfibrillar proteins of fish muscle.
Acsulfame-K - Saccharin - Cyclamate - Aspartame

34. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Yellow
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Sweet - Salty - Sour - and Bitter
Water

35. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
pH below positive charge; pH at no charge; pH above negative charge
RNA transcribed to DNA

36. What is the Peroxide Value a measure of?
Ascorbic Acid and Citric Acid
Monosodium Glutamate
Blue pigment in flowers
Fat Oxidation

37. How does HPLC differ from FPLC?
HPLC has higher pressure than FPLC
Emulsification
.05
Carrageenan

38. What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Carmelization and Maillard
It explodes
Initiation - Propagation - Termination

39. Waxes are composed of what two basic chemical entities?
Whole Milk
Daminozide
Fatty Acid (Ester linked) to Fatty Alcohol
14

40. Peptide bond formation results in the formation of what secondary compound?
HPLC has higher pressure than FPLC
Daminozide
Browning of freshly cut surfaces of fruits and vegetables.
Water

41. Name three effects of protein denaturation.
Chitin
The degree of liquid drainage or foam collapse (foam reduction) after a given time - the time for total or half-drainage (or half-reduction in volume) - or the time before drainage starts.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Water

42. What is the geometric configuration of double bonds in most natural fatty acids?
Cis
Whole Milk
Negative log of the hydrogen concentration (mol/l).
NaCl (it dissociated to a 2M solution)

43. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Tryptophan
The speed of a molecule is proportional to the surrounding voltage gradient.
Phenylketonuria
Anthocyanins

44. What are the fructose contents in commercial HFCS products.
45% - 52% - 90%
A concentrate of microfibrillar proteins of fish muscle.
Chitin
Lycopenes

45. How does HPLC differ from FPLC?
Onions ( or leeks)
HPLC has higher pressure than FPLC
Lipid oxidation
Milk

46. When heated ammonium bicarbonate decomposes to form what end products?
Yellow
Ammonia - Water - Carbon Dioxide
Polyphenol Oxidase
They are natural - nontoxic substances - generally catalyze without unwanted side-effects - active under very mild conditions of temperature and pH - active at low concentrations - rate of reaction can be controlled - can be inactivated after reactio

47. What is the winterization process for an oil?
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Pectin methyl esterase or galacturonase
Thickener in foods

48. Name two non-enzymatic browning reactions.
45% - 52% - 90%
Lipase
Carmelization and Maillard
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

49. Match the number of carbon atoms with the common name of these saturated fatty acids. Carbon #: 4:0 10:0 - 12:0 -14:0 - 16:0 - 18:0Common Name: Myristic - Butyric - Capric - Lauric - Stearic - Palmitic
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
RNA transcribed to DNA
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Lipid oxidation

50. How many polypeptide chains make up an antibody?
Four
20 carbons and 4 double bonds
Pheophytin forms
The speed of a molecule is proportional to the surrounding voltage gradient.