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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. At low water activity What is the main deteriorative concern?
Arachidonic Acid
Lipid oxidation
Sweet - Salty - Sour - and Bitter
Browning of freshly cut surfaces of fruits and vegetables.

2. What is the name given to a mixture of equal parts of Darel Lisomers?
Racemic Mixture
pH below positive charge; pH at no charge; pH above negative charge
Orange Juice
Acsulfame-K - Saccharin - Cyclamate - Aspartame

3. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
1 - 3 - 7-trimethylxanthine
Fat Oxidation
Bright green
Tryptophan

4. What does the iodine value measure and how is it measured?
pH 3-5
Polyphenols
Non-protein nitrogen
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

5. What is the geometric configuration of double bonds in most natural fatty acids?
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Cis
Sweet - Salty - Sour - and 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.

6. Name a naturally occurring protein sweetener.
Chitin
Thamautin
Pectins
Covalent (strongest) and Hydrophobic (Weakest)

7. Name 3 chemical agents capable of denaturing proteins.
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.
Cis
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

8. What is the structural difference between chlorophyll and chlocophyllide?
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)
A concentrate of microfibrillar proteins of fish muscle.
Chlocophyllide does not have a phytoltail

9. What are the limiting amino acids in corn - potato - and green peas?
Prolamines
Capsaicin
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
RNA transcribed to DNA

10. At low water activity What is the main deteriorative concern?
Lipid oxidation
Pheophytia does not have magnesium in porphyrin ring.
pH 3-5
Pectin Esterase - Polygalacturonase - Pectin Layase

11. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Carmelization and Maillard
Carrageenan
Pheophytia does not have magnesium in porphyrin ring.

12. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Prolamines
Blue pigment in flowers
Plasmids
Olive Green

13. How can a molecular weight of protein - DNA - and RNA be determined?
Fatty Acid and Alcohol
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Daminozide
45% - 52% - 90%

14. What is the enzyme that softens tomatoes?
Pectin Esterase
Pectin methyl esterase or galacturonase
It explodes
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

15. Name the two components that comprise the relaxing factor in muscle fibers.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Troponins and Tropomyosin
Speed of Light
D: None of the above

16. What is catalase?
An enzyme that converts hydrogen peroxide to water plus oxygen.
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.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Whole Milk

17. What is Carboxy-methyl cellulose often used for?
Oil in Water
Yes
Plasmids
Thickener in foods

18. What is an isomer that is cheaper than Vitamin C?
NaCl (it dissociated to a 2M solution)
Monosodium Glutamate
Erythorbic Acid
Aspartic Acid and Phenylalanine

19. Name 5 chelating agents used in the food industry.
Speed of Light
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Lysine - Arginine - and Histidine
Initiation - Propagation - and Termination

20. Alar is the trade name for what chemical compound?
Monosodium Glutamate
Daminozide
Primary butyric acid also caproic acid.
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.

21. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
RNA transcribed to DNA
Yes
They act as catalysts - speeding the polymerization of acrylamide.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls

22. Name the most common functional property of phospholipids in food systems.
Emulsification
Chlocophyllide does not have a phytoltail
Fructose
Tryptophan

23. How does ERH relate to water activity?
ERH=100 x Aw
Fatty Acid and Alcohol
Covalent (strongest) and Hydrophobic (Weakest)
Sweet - Salty - Sour - and Bitter

24. What does the saponification value measure and how is it measured?
Sweet - Salty - Sour - and Bitter
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Monosodium Glutamate

25. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Polyphenol Oxidase
Carmelization and Maillard
V=IR and P=VI or I x I x are
Plasmids

26. Name three nonpolar polar - and charged amino acids.
Non-protein nitrogen
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
NaCl (it dissociated to a 2M solution)

27. What is the major color compound in tomatoes?
Pectin methyl esterase or galacturonase
Lycopenes
Whole Milk
Blue pigment in flowers

28. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
Covalent (strongest) and Hydrophobic (Weakest)
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Two aldehydes

29. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
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.
Sucrose
Tryptophan
Non-protein nitrogen

30. Name 3 factors influencing the consistency of commercial fats.
Carrageenan
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
.05 M HCL
Pectin Esterase - Polygalacturonase - Pectin Layase

31. What charge will a protein have when the pH of its solution is below at - and above its pKa?
pH below positive charge; pH at no charge; pH above negative charge
Browning of freshly cut surfaces of fruits and vegetables.
Sucrose
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

32. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Linoleic Acid
pH below positive charge; pH at no charge; pH above negative charge
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

33. Name the two components that comprise the relaxing factor in muscle fibers.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Fructose
Troponins and Tropomyosin
.05

34. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
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.
NaCl (it dissociated to a 2M solution)
Lamellar; Hexagonal I - II; Cubic
Yellow

35. What is the structural difference between chlorophyll and chlocophyllide?
Polyphenols
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.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Chlocophyllide does not have a phytoltail

36. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Pheophytin forms
Chitin
V=IR and P=VI or I x I x are
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

37. What is the structural difference between chlorophyll and pheophytia?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Four
Pheophytia does not have magnesium in porphyrin ring.
Water

38. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Capsaicin
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Negative log of the hydrogen concentration (mol/l).
Polyphenoloxidase

39. Name two enzymes that are involved in softening fruits.
Pectin Esterase - Polygalacturonase - Pectin Layase
ERH=100 x Aw
Pectin Esterase
Ammonia - Water - Carbon Dioxide

40. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Glycosides of anthocyanidins
pH below positive charge; pH at no charge; pH above negative charge
Polyphenol Oxidase
Bright green

41. 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.
Thamautin
Aspartic Acid and Phenylalanine
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

42. Name one way foam stability can be assessed.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Anthocyanins
Parabens
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.

43. In what food is butyric acid typically found?
Milk
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Whole Milk
Phenophylin

44. When heated ammonium bicarbonate decomposes to form what end products?
Fructose
Ammonia - Water - Carbon Dioxide
Carrageenan
Milk

45. What is the chemical nature of anthocyanins?
Bitter
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.
They act as catalysts - speeding the polymerization of acrylamide.
Glycosides of anthocyanidins

46. What pigment was first designated as anthocyanins?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
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.
They act as catalysts - speeding the polymerization of acrylamide.

47. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
Sucrose
ERH=100 x Aw
pH 3-5

48. How do sodium chloride and sucrose affect foam stability?
Polyphenoloxidase
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Two aldehydes

49. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
20 carbons and 4 double bonds
Thermus Aqauticus
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

50. What is acid proteolysis?
Degradation of protein and production of acid from sugar at the same time.
Fat Oxidation
Thermus Aqauticus
They act as catalysts - speeding the polymerization of acrylamide.