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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 the name given to a mixture of equal parts of Darel Lisomers?
Racemic Mixture
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Sweet - Salty - Sour - and Bitter
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

2. What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Monosodium Glutamate
V=IR and P=VI or I x I x are
Polyphenoloxidase

3. Name a commonly used household chemical leavening agent and the gas it generates.
Plasmids
Yes
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Sodium bicarbonate generates CO2

4. In the enzyme Taq Polymerase What does Taq stand for?
Thermus Aqauticus
NaCl (it dissociated to a 2M solution)
Phenophylin
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

5. Alar is the trade name for what chemical compound?
Daminozide
Pectins
Whole Milk
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

6. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Whole Milk
pH 3-5
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
RNA transcribed to DNA

7. 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
Troponins and Tropomyosin
Browning of freshly cut surfaces of fruits and vegetables.
Primary butyric acid also caproic acid.
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

8. Name a commonly used household chemical leavening agent and the gas it generates.
Sodium bicarbonate generates CO2
Emulsification
Tryptophan
Plasmids

9. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
They act as catalysts - speeding the polymerization of acrylamide.
Sweet - Salty - Sour - and Bitter
Water
Phenylketonuria

10. What is the Peroxide Value a measure of?
Thamautin
Orange Juice
Lysine - Arginine - and Histidine
Fat Oxidation

11. What is the structural difference between chlorophyll and pheophytia?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Initiation - Propagation - Termination
Anthocyanins
Pheophytia does not have magnesium in porphyrin ring.

12. What are the three main steps in the autooxidation of lipids?
Tryptophan
Initiation - Propagation - Termination
Plasmids
Daminozide

13. What does Reichert-Meissert Number measure?
No
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Ascorbic Acid and Citric Acid
Primary butyric acid also caproic acid.

14. What is the enzyme that softens tomatoes?
Emulsoids
Primary butyric acid also caproic acid.
Pectin Esterase
Fatty Acid and Alcohol

15. Name 3 reasons it is advantageous to obtain enzymes from microorganisms.

16. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Onions ( or leeks)
Thickener in foods
Linoleic Acid
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

17. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Polyphenol Oxidase
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
pH below positive charge; pH at no charge; pH above negative charge
Pectin Esterase - Polygalacturonase - Pectin Layase

18. Name two reasons why fats are hydrogenated.
Glycosides of anthocyanidins
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Yellow

19. How can a molecular weight of protein - DNA - and RNA be determined?
Ammonia - Water - Carbon Dioxide
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
V=IR and P=VI or I x I x are

20. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Lipid oxidation
Plasmids
Bright green

21. What is the protein efficiency ratio (PER) of casein?
Degradation of protein and production of acid from sugar at the same time.
2.5
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Primary butyric acid also caproic acid.

22. Name 3 chemical agents capable of denaturing proteins.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Initiation - Propagation - and Termination
It explodes
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

23. What metabolic end product does the Voges-Proskauer test detect?
Phenophylin
Lysine - Arginine - and Histidine
Racemic Mixture
Acetoin

24. What does MSG stand for?
Primary butyric acid also caproic acid.
Monosodium Glutamate
Bitter
Osmosis

25. Is a disaccharide
Lycopenes
Sucrose
Yellow
Pectins

26. How many polypeptide chains make up an antibody?
Lycopenes
Four
Whole Milk
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.

27. Name 3 physical agents capable of denaturing proteins.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Bright green
Pheophytin forms
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

28. What are the limiting amino acids in corn - potato - and green peas?
Tryptophan
Phenylketonuria
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.

29. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
A concentrate of microfibrillar proteins of fish muscle.
Olive Green
Lycopenes

30. Name one way foam stability can be assessed.
Degradation of protein and production of acid from sugar at the same time.
Anthocyanins
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
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.

31. What toxic pigment is found in cottonseed endosperm?
Initiation - Propagation - and Termination
Gossypol (it is removed during the oil refining process)
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Water

32. What is the enzyme that softens tomatoes?
Sucrose
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Blue pigment in flowers
Pectin Esterase

33. What enzyme is most responsible for browning bananas?
Chitin
45% - 52% - 90%
Whole Milk
Polyphenol Oxidase

34. How many polypeptide chains make up an antibody?
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Four
It explodes
Nucleation or crystal formation and crystal growth.

35. What is the fundamental driving of electrophoresis?
RNA transcribed to DNA
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 speed of a molecule is proportional to the surrounding voltage gradient.
Bitter

36. Name 3 factors influencing the rate of lipid oxidation in foods.
No
Linoleic Acid
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
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.

37. Alar is the trade name for what chemical compound?
Lipid oxidation
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Bitter
Daminozide

38. Name two main gluten proteins.
Pectin methylesterase & polygalacturonase
Gliadins and Glutenins
Water
Chitin

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

40. 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?
Fructose
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
.05 M HCL
Oil in Water

41. What are two common reducing agents that break disulfide bonds in proteins?
.05 M HCL
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
45% - 52% - 90%

42. Name two reasons why fats are hydrogenated.
Plasmids
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
pH below positive charge; pH at no charge; pH above negative charge
Capsaicin

43. Name 3 physical agents capable of denaturing proteins.
Prolamines
Fatty Acid (Ester linked) to Fatty Alcohol
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

44. What is the chemical nature of anthocyanins?
Sodium bicarbonate generates CO2
Glycosides of anthocyanidins
Degradation of protein and production of acid from sugar at the same time.
Polyphenol Oxidase

45. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Phenophylin
D: None of the above
pH below positive charge; pH at no charge; pH above negative charge
Pectins

46. What is the fundamental driving of electrophoresis?
pH 3-5
Bright green
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
The speed of a molecule is proportional to the surrounding voltage gradient.

47. What are 3 mesomorphic structures associated with lipids in the liquid state?
Emulsoids
Lamellar; Hexagonal I - II; Cubic
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Water

48. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Daminozide
Pheophytia does not have magnesium in porphyrin ring.
Erythorbic Acid
Orange Juice

49. What is the name of the degradation compound of chlorophyll?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and 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.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Phenophylin

50. Name 4 advantages of using enzymes in food processing.
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
Ammonia - Water - Carbon Dioxide
Lipid oxidation
Phenophylin