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. Name 3 physical agents capable of denaturing proteins.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Erythorbic Acid
Emulsoids
Thamautin

2. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Aspartic Acid and Phenylalanine
Glycosides of anthocyanidins
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Bright green

3. What would be a safe processing time for heat processing green beans in a boiling water bath? A. 30 minutes B. 300 minutes C. Depends on the size of the food container D. None of the above
Plasmids
Capsaicin
Orange Juice
D: None of the above

4. Are sorbitol and mannitol sweet?
Yes
Pectin methyl esterase or galacturonase
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
Fructose

5. How does HPLC differ from FPLC?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Gossypol (it is removed during the oil refining process)
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
HPLC has higher pressure than FPLC

6. Does kosmotrophil ion discourage water structure?
Troponins and Tropomyosin
No
pH below positive charge; pH at no charge; pH above negative charge
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

7. What is the Peroxide Value a measure of?
ERH=100 x Aw
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Fat Oxidation

8. What is an isomer that is cheaper than Vitamin C?
Polyphenol Oxidase
Erythorbic Acid
Sodium chloride reduces foam stability and sucrose improves foam stability.
Bitter

9. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Initiation - Propagation - Termination
Capsaicin
No

10. What is the fundamental driving of electrophoresis?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Covalent (strongest) and Hydrophobic (Weakest)
The speed of a molecule is proportional to the surrounding voltage gradient.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

11. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Lipid oxidation
Polyphenoloxidase
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Aspartic Acid and Phenylalanine

12. What happens to chlorophyll on heating?
Pheophytin forms
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
.05 M HCL
No

13. How many carbon atoms are there in the fatty acid myristic acid?
14
Carrageenan
HPLC has higher pressure than FPLC
Lamellar; Hexagonal I - II; Cubic

14. How do sodium chloride and sucrose affect foam stability?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
HPLC has higher pressure than FPLC
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Sodium chloride reduces foam stability and sucrose improves foam stability.

15. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Tryptophan
Sodium bicarbonate generates CO2
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Thickener in foods

16. What is the chemical nature of anthocyanins?
Glycosides of anthocyanidins
Cis
Pectin methyl esterase or galacturonase
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

17. How can a molecular weight of protein - DNA - and RNA be determined?
Lamellar; Hexagonal I - II; Cubic
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Sucrose
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

18. What does MSG stand for?
Lysine - Arginine - and Histidine
Monosodium Glutamate
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Arachidonic Acid

19. What are colloids that are stabilized by a layer of solvation called?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
NaCl (it dissociated to a 2M solution)
Two aldehydes
Emulsoids

20. What are 3 mesomorphic structures associated with lipids in the liquid state?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
.05 M HCL
Polyphenol Oxidase
Lamellar; Hexagonal I - II; Cubic

21. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Onions ( or leeks)
Acetoin
Sodium chloride reduces foam stability and sucrose improves foam stability.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

22. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
V=IR and P=VI or I x I x are
Negative log of the hydrogen concentration (mol/l).
Chitin
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

23. At low water activity What is the main deteriorative concern?
Lipid oxidation
Nucleation or crystal formation and crystal growth.
Gossypol (it is removed during the oil refining process)
Orange Juice

24. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Carrageenan
Emulsification
Orange Juice

25. In what food is butyric acid typically found?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Milk
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Racemic Mixture

26. What is the fundamental driving of electrophoresis?
Arachidonic Acid
The speed of a molecule is proportional to the surrounding voltage gradient.
Pectin methylesterase & polygalacturonase
An enzyme that converts hydrogen peroxide to water plus oxygen.

27. What does HLB stand for and What does a high and low HLB value indicate?
Lipid oxidation
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
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.
Negative log of the hydrogen concentration (mol/l).

28. At what pH is benzoic acid most effective?
Pectin methyl esterase or galacturonase
Ascorbic Acid and Citric Acid
Browning of freshly cut surfaces of fruits and vegetables.
pH 3-5

29. What is the protein efficiency ratio (PER) of casein?
Monosodium Glutamate
Blue pigment in flowers
Orange Juice
2.5

30. How many polypeptide chains make up an antibody?
Pheophytia does not have magnesium in porphyrin ring.
A concentrate of microfibrillar proteins of fish muscle.
Four
Arachidonic Acid

31. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Tryptophan
Pectin methyl esterase or galacturonase
Orange Juice

32. In the enzyme Taq Polymerase What does Taq stand for?
Chitin
Sucrose
Thermus Aqauticus
Water

33. At low water activity What is the main deteriorative concern?
Polyphenols
Pheophytia does not have magnesium in porphyrin ring.
Carmelization and Maillard
Lipid oxidation

34. Name 5 proteins with good foaming properties.
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.
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.
Pheophytin forms
Polyphenols

35. 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
Onions ( or leeks)
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Osmosis

36. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Negative log of the hydrogen concentration (mol/l).
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
1 - 3 - 7-trimethylxanthine
Carmelization and Maillard

37. 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
Sodium chloride reduces foam stability and sucrose improves foam stability.
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Water
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

38. Name 3 factors influencing the rate of lipid oxidation in foods.
Four
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

39. Name the strongest biochemical bond and the weakest biochemical bond.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Covalent (strongest) and Hydrophobic (Weakest)
Bitter

40. What does Acid Degree Value measure and how is it measured?
Two aldehydes
Carrageenan
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Sodium chloride reduces foam stability and sucrose improves foam stability.

41. What are the fructose contents in commercial HFCS products.
Oil in Water
Fatty Acid and Alcohol
Pheophytin forms
45% - 52% - 90%

42. What are proteins which are soluble in 50-80% ethanol known as?
Pheophytin forms
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Prolamines
Monosodium Glutamate

43. Name three non-nutritive sweeteners approved for use in USA?
Pectin methyl esterase or galacturonase
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Nucleation or crystal formation and crystal growth.
Emulsification

44. What metabolic end product does the Voges-Proskauer test detect?
Phenylketonuria
Daminozide
Thermus Aqauticus
Acetoin

45. What does the iodine value measure and how is it measured?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Olive Green
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
D: None of the above

46. What is the enzyme that softens tomatoes?
Fatty Acid and Alcohol
Phenylketonuria
Ascorbic Acid and Citric Acid
Pectin Esterase

47. What is the structural difference between chlorophyll and chlocophyllide?
Thamautin
Plasmids
Thermus Aqauticus
Chlocophyllide does not have a phytoltail

48. Will lipid oxidation be higher at a water activity of .05 or .5?
.05
ERH=100 x Aw
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Troponins and Tropomyosin

49. 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
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Pheophytin forms

50. What is Carboxy-methyl cellulose often used for?
Phenophylin
An enzyme that converts hydrogen peroxide to water plus oxygen.
Thickener in foods
Pectin methyl esterase or galacturonase