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. What compounds oxidize to form brown color in fruits and vegetables?
Aspartic Acid and Phenylalanine
Emulsification
Polyphenols
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

2. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Plasmids
Emulsoids
Bitter
Bright green

3. Name the most common functional property of phospholipids in food systems.
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Water
Emulsification
Initiation - Propagation - and Termination

4. Is a disaccharide
20 carbons and 4 double bonds
Sucrose
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
1 - 3 - 7-trimethylxanthine

5. What metabolic end product does the Voges-Proskauer test detect?
Acetoin
Phenophylin
Oil in Water
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

6. Name 3 factors influencing the rate of lipid oxidation in foods.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
It explodes
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.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

7. What two common compounds are used together as an antioxidative system?
Erythorbic Acid
Ascorbic Acid and Citric Acid
Thermus Aqauticus
Chlocophyllide does not have a phytoltail

8. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Ammonia - Water - Carbon Dioxide
Polyphenols
Anomeric
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

9. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Cis
Linoleic Acid
Water
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.

10. What is the enzyme responsible for browning in apples and lettuce?
Aspartic Acid and Phenylalanine
Lysine - Arginine - and Histidine
Capsaicin
Polyphenol Oxidase

11. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
1 - 3 - 7-trimethylxanthine
HPLC has higher pressure than FPLC
Lysine - Arginine - and Histidine
Two aldehydes

12. What happens to a bottle of wine if before you bottle it you forget to put the stuff in it that prevents it from fermenting?
Chlocophyllide does not have a phytoltail
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.
It explodes
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

13. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Pectins
Bitter
Racemic Mixture
V=IR and P=VI or I x I x are

14. What does Reichert-Meissert Number measure?
Polyphenol Oxidase
Sodium chloride reduces foam stability and sucrose improves foam stability.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Primary butyric acid also caproic acid.

15. At what pH is benzoic acid most effective?
Lipase
Sodium bicarbonate generates CO2
pH 3-5
Cis

16. Name two non-enzymatic browning reactions.
Pectin methylesterase & polygalacturonase
Carmelization and Maillard
Linoleic Acid
pH 3-5

17. What does the iodine value measure and how is it measured?
Orange Juice
Lysine - Arginine - and Histidine
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

18. What is Carboxy-methyl cellulose often used for?
Thickener in foods
Pheophytin forms
Capsaicin
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

19. What are proteins which are soluble in 50-80% ethanol known as?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Prolamines
Yellow
Blue pigment in flowers

20. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Gliadins and Glutenins
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.
pH below positive charge; pH at no charge; pH above negative charge
Glycosides of anthocyanidins

21. What is the Peroxide Value a measure of?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Fat Oxidation
Carmelization and Maillard
Covalent (strongest) and Hydrophobic (Weakest)

22. Name 3 chemical agents capable of denaturing proteins.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Negative log of the hydrogen concentration (mol/l).
Primary butyric acid also caproic acid.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

23. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Arachidonic Acid
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Pheophytin forms
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.

24. What two common compounds are used together as an antioxidative system?
Onions ( or leeks)
Polyphenols
Polyphenol Oxidase
Ascorbic Acid and Citric Acid

25. What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Troponins and Tropomyosin
Oil in Water
Lipid oxidation

26. Name two enzymes that are involved in softening fruits.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Phenophylin
Ascorbic Acid and Citric Acid
Pectin Esterase - Polygalacturonase - Pectin Layase

27. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Tryptophan
20 carbons and 4 double bonds
Negative log of the hydrogen concentration (mol/l).
Oil in Water

28. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
2.5
Bitter
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.
They act as catalysts - speeding the polymerization of acrylamide.

29. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Primary butyric acid also caproic acid.
Lysine - Arginine - and Histidine
D: None of the above

30. What toxic pigment is found in cottonseed endosperm?
Carmelization and Maillard
Gossypol (it is removed during the oil refining process)
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
1 - 3 - 7-trimethylxanthine

31. What are the fructose contents in commercial HFCS products.
45% - 52% - 90%
Thamautin
Sodium bicarbonate generates CO2
Thermus Aqauticus

32. How is pH defined?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Negative log of the hydrogen concentration (mol/l).
Daminozide
Pectin methylesterase & polygalacturonase

33. Name one way foam stability can be assessed.
Lysine - Arginine - and Histidine
Two aldehydes
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.
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.

34. Name the three positively charged amino acids.
Plasmids
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
1 - 3 - 7-trimethylxanthine
Lysine - Arginine - and Histidine

35. What effect would the addition of sodium bicarbonate have to chocolate?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Microorganisms are very versatile - MO's can be altered by mutations or genetic engineering to produce a greater quantity of enzyme or different enzymes - recovery of enzymes is often easy - readily available - high rate of growth and enzyme producti
Milk
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

36. Name 4 advantages of using enzymes in food processing.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
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
Acsulfame-K - Saccharin - Cyclamate - Aspartame
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.

37. Which two amino acids is the aspartame derived from?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Blue pigment in flowers
Aspartic Acid and Phenylalanine

38. What is the winterization process for an oil?
Tryptophan
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Browning of freshly cut surfaces of fruits and vegetables.
Chitin

39. Name three effects of protein denaturation.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Osmosis
They act as catalysts - speeding the polymerization of acrylamide.
Polyphenol Oxidase

40. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
It explodes
Olive Green
Polyphenol Oxidase
Sodium chloride reduces foam stability and sucrose improves foam stability.

41. What happens to chlorophyll on heating?
Yes
Pheophytin forms
Onions ( or leeks)
Capsaicin

42. What enzyme is most responsible for browning bananas?
Polyphenol Oxidase
Whole Milk
pH below positive charge; pH at no charge; pH above negative charge
.05

43. During freezing What are the two stages in the crystallization process?
Lycopenes
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.
Nucleation or crystal formation and crystal growth.
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.

44. What does HLB stand for and What does a high and low HLB value indicate?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
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.
Lycopenes
14

45. What does the saponification value measure and how is it measured?
Water
.05 M HCL
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Erythorbic Acid

46. At low water activity What is the main deteriorative concern?
Lipid oxidation
Monosodium Glutamate
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 are the three stages of oxidative rancidity?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Bright green
2.5
Initiation - Propagation - and Termination

48. What is acid proteolysis?
Degradation of protein and production of acid from sugar at the same time.
Primary butyric acid also caproic acid.
Non-protein nitrogen
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

49. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
2.5
Bright green
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Cis

50. Does kosmotrophil ion discourage water structure?
No
Emulsoids
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.
Polyphenols