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Food Chemistry

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Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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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 is Carboxy-methyl cellulose often used for?
Polyphenol Oxidase
Thickener in foods
Sodium chloride reduces foam stability and sucrose improves foam stability.
Ammonia - Water - Carbon Dioxide

2. What metabolic end product does the Voges-Proskauer test detect?
Daminozide
Acetoin
Initiation - Propagation - Termination
Orange Juice

3. Name a commonly used household chemical leavening agent and the gas it generates.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Sodium bicarbonate generates CO2
Emulsoids

4. During freezing What are the two stages in the crystallization process?
Lysine - Arginine - and Histidine
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Nucleation or crystal formation and crystal growth.
Carrageenan

5. Name the most common functional property of phospholipids in food systems.
Thickener in foods
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Bright green
Emulsification

6. What is an isomer that is cheaper than Vitamin C?
.05 M HCL
Erythorbic Acid
Acetoin
pH 3-5

7. 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
NaCl (it dissociated to a 2M solution)
Whole Milk
Troponins and Tropomyosin

8. Which of the following examples of browning is enzymatic in nature? 1. Browning of sugars as a result of heating 2. Browning of freshly cut surfaces of fruits and vegetables 3. Browning of bread during toasting 4. Browning of potato chips
Sodium bicarbonate generates CO2
Lipase
Covalent (strongest) and Hydrophobic (Weakest)
Browning of freshly cut surfaces of fruits and vegetables.

9. Name the strongest biochemical bond and the weakest biochemical bond.
ERH=100 x Aw
Chitin
Covalent (strongest) and Hydrophobic (Weakest)
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

10. What is the structural difference between chlorophyll and chlocophyllide?
Bitter
Racemic Mixture
.05
Chlocophyllide does not have a phytoltail

11. What does Acid Degree Value measure and how is it measured?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
An enzyme that converts hydrogen peroxide to water plus oxygen.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
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.

12. What ketohexose is most significant to food chemists?
Fructose
Whole Milk
Troponins and Tropomyosin
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

13. In what food is butyric acid typically found?
Water
Emulsification
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Milk

14. Name 3 physical agents capable of denaturing proteins.
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Onions ( or leeks)
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Gossypol (it is removed during the oil refining process)

15. What compounds oxidize to form brown color in fruits and vegetables?
Sucrose
Pheophytin forms
Initiation - Propagation - and Termination
Polyphenols

16. Name 3 chemical agents capable of denaturing proteins.
Plasmids
Primary butyric acid also caproic acid.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

17. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Bright green
Plasmids
Pectin methyl esterase or galacturonase
Two aldehydes

18. What is the Peroxide Value a measure of?
Initiation - Propagation - and Termination
Glycosides of anthocyanidins
Anomeric
Fat Oxidation

19. Name 3 chemical agents capable of denaturing proteins.
Polyphenoloxidase
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Whole Milk
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

20. What does Reichert-Meissert Number measure?
Primary butyric acid also caproic acid.
Polyphenol Oxidase
Olive Green
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

21. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Sodium chloride reduces foam stability and sucrose improves foam stability.
Polyphenols

22. Name two reasons why fats are hydrogenated.
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.
Pectins
Anthocyanins
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

23. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Osmosis
Initiation - Propagation - Termination
2.5
HPLC has higher pressure than FPLC

24. Does kosmotrophil ion discourage water structure?
No
Monosodium Glutamate
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Lipase

25. What are two common reducing agents that break disulfide bonds in proteins?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Initiation - Propagation - Termination
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
45% - 52% - 90%

26. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Pectins
Milk
Lamellar; Hexagonal I - II; Cubic
Tryptophan

27. At what pH is benzoic acid most effective?
Lamellar; Hexagonal I - II; Cubic
pH 3-5
D: None of the above
Fatty Acid (Ester linked) to Fatty Alcohol

28. What is the enzyme that softens tomatoes?
Daminozide
Pectin Esterase
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
pH 3-5

29. What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Capsaicin

30. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Blue pigment in flowers
Water
Lysine - Arginine - and Histidine
Carrageenan

31. Define molarity molality - and normality.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
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.
45% - 52% - 90%
NaCl (it dissociated to a 2M solution)

32. What does MSG stand for?
Lysine - Arginine - and Histidine
Degradation of protein and production of acid from sugar at the same time.
D: None of the above
Monosodium Glutamate

33. How many carbon atoms are there in the fatty acid myristic acid?
Lipase
Non-protein nitrogen
Parabens
14

34. What is Carboxy-methyl cellulose often used for?
Thickener in foods
Non-protein nitrogen
Daminozide
Fructose

35. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Pheophytin forms
Primary butyric acid also caproic acid.
It explodes

36. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Plasmids
pH below positive charge; pH at no charge; pH above negative charge
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Troponins and Tropomyosin

37. Name the most common functional property of phospholipids in food systems.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Emulsification
Polyphenoloxidase
Orange Juice

38. Name the strongest biochemical bond and the weakest biochemical bond.
Covalent (strongest) and Hydrophobic (Weakest)
HPLC has higher pressure than FPLC
DNA transferred by cell to cell contact (bacterial sex).
Fatty Acid and Alcohol

39. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Lamellar; Hexagonal I - II; Cubic
Chitin
Lycopenes
Sodium chloride reduces foam stability and sucrose improves foam stability.

40. Name 5 chelating agents used in the food industry.
Pectin Esterase
D: None of the above
1 - 3 - 7-trimethylxanthine
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

41. Name three nonpolar polar - and charged amino acids.
NaCl (it dissociated to a 2M solution)
Negative log of the hydrogen concentration (mol/l).
D: None of the above
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

42. What is the chemical nature of anthocyanins?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Carrageenan
Glycosides of anthocyanidins
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

43. What does HLB stand for and What does a high and low HLB value indicate?
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.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
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)

44. 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?
Fat Oxidation
Sodium bicarbonate generates CO2
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
It explodes

45. Name three factors useful in controlling enzyme activity.
Pectin methyl esterase or galacturonase
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Aspartic Acid and Phenylalanine
Negative log of the hydrogen concentration (mol/l).

46. What happens to chlorophyll on heating?
Racemic Mixture
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
Pheophytin forms
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

47. If you take 20 ml of .1 M NaOH to titrate 40 mL of an HCL solution to the penolphthalein end point What is the molarity of the HCL solution?
.05 M HCL
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Sodium chloride reduces foam stability and sucrose improves foam stability.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

48. At low water activity What is the main deteriorative concern?
Daminozide
Water
Yes
Lipid oxidation

49. Give one word for a carbon atom involved in hemiacetal or acetal formation.
An enzyme that converts hydrogen peroxide to water plus oxygen.
Anomeric
.05
It explodes

50. Name one way foam stability can be assessed.
Chitin
Ammonia - Water - Carbon Dioxide
pH below positive charge; pH at no charge; pH above negative charge
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.