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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 structural difference between chlorophyll and chlocophyllide?
Thamautin
Chlocophyllide does not have a phytoltail
Cis
Onions ( or leeks)

2. What is the enzyme that softens tomatoes?
ERH=100 x Aw
pH 3-5
Pectin Esterase
NaCl (it dissociated to a 2M solution)

3. What is the geometric configuration of double bonds in most natural fatty acids?
Cis
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Thamautin

4. What does the 'c' stand for in the equation E=mc2?
A concentrate of microfibrillar proteins of fish muscle.
Lipid oxidation
Ascorbic Acid and Citric Acid
Speed of Light

5. What are the three stages of oxidative rancidity?
Initiation - Propagation - and Termination
pH below positive charge; pH at no charge; pH above negative charge
Non-protein nitrogen
RNA transcribed to DNA

6. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
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.
Bright green
Polyphenol Oxidase
They act as catalysts - speeding the polymerization of acrylamide.

7. What is the name of the degradation compound of chlorophyll?
Anthocyanins
Bitter
Fatty Acid and Alcohol
Phenophylin

8. Name the strongest biochemical bond and the weakest biochemical bond.
NaCl (it dissociated to a 2M solution)
Phenylketonuria
Covalent (strongest) and Hydrophobic (Weakest)
.05 M HCL

9. What are the fructose contents in commercial HFCS products.
45% - 52% - 90%
Racemic Mixture
Pectins
Carrageenan

10. How many polypeptide chains make up an antibody?
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.
A concentrate of microfibrillar proteins of fish muscle.
Four
Thickener in foods

11. At low water activity What is the main deteriorative concern?
Sweet - Salty - Sour - and Bitter
Lipid oxidation
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Two aldehydes

12. What does the iodine value measure and how is it measured?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Aspartic Acid and Phenylalanine
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
No

13. Name two enzymes that are involved in softening fruits.
Tryptophan
Prolamines
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Pectin Esterase - Polygalacturonase - Pectin Layase

14. What is the main class of color compounds found in raspberries?
Anthocyanins
Whole Milk
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Bright green

15. 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
Lamellar; Hexagonal I - II; Cubic
Pectin methyl esterase or galacturonase
Browning of freshly cut surfaces of fruits and vegetables.
D: None of the above

16. Name the three positively charged amino acids.
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.
Initiation - Propagation - Termination
Lysine - Arginine - and Histidine
Lamellar; Hexagonal I - II; Cubic

17. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
pH 3-5
Yellow
1 - 3 - 7-trimethylxanthine
RNA transcribed to DNA

18. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Daminozide
Acetoin
Chitin
HPLC has higher pressure than FPLC

19. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
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
NaCl (it dissociated to a 2M solution)
Pectin Esterase - Polygalacturonase - Pectin Layase
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

20. What does the saponification value measure and how is it measured?
Two aldehydes
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
2.5

21. Name three effects of protein denaturation.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Emulsoids
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.

22. How does HPLC differ from FPLC?
Pectin methyl esterase or galacturonase
Ascorbic Acid and Citric Acid
Aspartic Acid and Phenylalanine
HPLC has higher pressure than FPLC

23. What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
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.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
pH 3-5

24. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Ammonia - Water - Carbon Dioxide
Tryptophan
Fructose
Lipid oxidation

25. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
Polyphenoloxidase
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Initiation - Propagation - Termination
Capsaicin

26. How do sodium chloride and sucrose affect foam stability?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Ascorbic Acid and Citric Acid
Sodium chloride reduces foam stability and sucrose improves foam stability.
Primary butyric acid also caproic acid.

27. What is surimi?
Negative log of the hydrogen concentration (mol/l).
Polyphenol Oxidase
A concentrate of microfibrillar proteins of fish muscle.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

28. Name 3 factors influencing the consistency of commercial fats.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Erythorbic Acid
Cis

29. 20 grams of amylose is added to 80 grams of water in a bearker; the boiling point is measured with an ordinary mercury-in-glass thermometer. What is the observed boiling point of the material in the beaker?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

30. What is the structural difference between chlorophyll and pheophytia?
Monosodium Glutamate
Pheophytia does not have magnesium in porphyrin ring.
Fatty Acid and Alcohol
Polyphenol Oxidase

31. How many carbon atoms are there in the fatty acid myristic acid?
14
NaCl (it dissociated to a 2M solution)
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Water

32. What is the acid present in fish oil?
Ammonia - Water - Carbon Dioxide
1 - 3 - 7-trimethylxanthine
Arachidonic Acid
Pectin methyl esterase or galacturonase

33. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Orange Juice
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Olive Green
14

34. Peptide bond formation results in the formation of what secondary compound?
Polyphenol Oxidase
Linoleic Acid
RNA transcribed to DNA
Water

35. What two types of compounds are joined with an ester bond to make a wax?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Speed of Light
Fatty Acid and Alcohol
Nucleation or crystal formation and crystal growth.

36. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Anomeric
1 - 3 - 7-trimethylxanthine
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Phenylketonuria

37. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Sucrose
.05 M HCL
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

38. Define molarity molality - and normality.
Emulsoids
Initiation - Propagation - Termination
Prolamines
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

39. What effect would the addition of sodium bicarbonate have to chocolate?
Lysine - Arginine - and Histidine
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Olive Green
Lipase

40. What happens to chlorophyll on heating?
Pheophytin forms
Orange Juice
Onions ( or leeks)
Initiation - Propagation - Termination

41. What is the major color compound in tomatoes?
Lycopenes
Oil in Water
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.
Fatty Acid (Ester linked) to Fatty Alcohol

42. What are the limiting amino acids in corn - potato - and green peas?
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
RNA transcribed to DNA

43. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Initiation - Propagation - and Termination
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Chitin
Linoleic Acid

44. Name 5 proteins with good foaming properties.
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.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Lycopenes
Sweet - Salty - Sour - and Bitter

45. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Bitter
Pectin methylesterase & polygalacturonase
Thermus Aqauticus
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

46. What are two common reducing agents that break disulfide bonds in proteins?
Phenophylin
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Parabens
Daminozide

47. What are the limiting amino acids in corn - potato - and green peas?
Pectins
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
A concentrate of microfibrillar proteins of fish muscle.
Onions ( or leeks)

48. What two enzymes degrade pectic substances?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
An enzyme that converts hydrogen peroxide to water plus oxygen.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Pectin methylesterase & polygalacturonase

49. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Pectin methylesterase & polygalacturonase
Bright green
Lycopenes
Monosodium Glutamate

50. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Gliadins and Glutenins
Aspartic Acid and Phenylalanine
Water
Olive Green