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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. Name the strongest biochemical bond and the weakest biochemical bond.
Polyphenols
V=IR and P=VI or I x I x are
Covalent (strongest) and Hydrophobic (Weakest)
Pheophytin forms

2. Alar is the trade name for what chemical compound?
A concentrate of microfibrillar proteins of fish muscle.
1 - 3 - 7-trimethylxanthine
Daminozide
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

3. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
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.
Four
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral 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.

4. Define molarity molality - and normality.
Plasmids
Thickener in foods
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

5. What does the iodine value measure and how is it measured?
Fatty Acid (Ester linked) to Fatty Alcohol
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Primary butyric acid also caproic acid.
They act as catalysts - speeding the polymerization of acrylamide.

6. What enzyme is most responsible for browning bananas?
Olive Green
Thermus Aqauticus
Monosodium Glutamate
Polyphenol Oxidase

7. How does HPLC differ from FPLC?
Cis
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
HPLC has higher pressure than FPLC
Plasmids

8. Name 5 chelating agents used in the food industry.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Water
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

9. Name 3 physical agents capable of denaturing proteins.
Arachidonic Acid
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
pH below positive charge; pH at no charge; pH above negative charge
Daminozide

10. What would be a safe processing time for heat processing green beans in a boiling water bath? A. 30 minutes B. 300 minutes C. Depends on the size of the food container D. None of the above
Yes
Monosodium Glutamate
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
D: None of the above

11. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
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
20 carbons and 4 double bonds
Oil in Water

12. What are the primary secondary - tertiary - and quaternary structures?
Pheophytin forms
Lipase
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.
Chitin

13. Name one way foam stability can be assessed.
Sucrose
Thermus Aqauticus
Chitin
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.

14. What is the chemical nomenclature for caffeine?
Pectin Esterase - Polygalacturonase - Pectin Layase
Emulsoids
Pectin Esterase
1 - 3 - 7-trimethylxanthine

15. Peptide bond formation results in the formation of what secondary compound?
Water
pH below positive charge; pH at no charge; pH above negative charge
Capsaicin
45% - 52% - 90%

16. What enzyme causes hyrolytic rancidity in milk?
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Lipase
HPLC has higher pressure than FPLC
14

17. Name 3 physical agents capable of denaturing proteins.
Lamellar; Hexagonal I - II; Cubic
Primary butyric acid also caproic acid.
Thamautin
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

18. What are colloids that are stabilized by a layer of solvation called?
Carmelization and Maillard
Negative log of the hydrogen concentration (mol/l).
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Emulsoids

19. What is the Peroxide Value a measure of?
Fat Oxidation
Initiation - Propagation - Termination
Thamautin
Pectin methyl esterase or galacturonase

20. 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?
Yes
Anomeric
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Thamautin

21. What is the structural difference between chlorophyll and pheophytia?
Pheophytia does not have magnesium in porphyrin ring.
14
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

22. During freezing What are the two stages in the crystallization process?
Water
Nucleation or crystal formation and crystal growth.
Blue pigment in flowers
Tryptophan

23. What pigment was first designated as anthocyanins?
Water
A concentrate of microfibrillar proteins of fish muscle.
Blue pigment in flowers
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

24. At what pH is benzoic acid most effective?
They act as catalysts - speeding the polymerization of acrylamide.
Four
pH 3-5
Pectin methylesterase & polygalacturonase

25. What two common compounds are used together as an antioxidative system?
Blue pigment in flowers
Ascorbic Acid and Citric Acid
Osmosis
Acetoin

26. Waxes are composed of what two basic chemical entities?
Fatty Acid (Ester linked) to Fatty Alcohol
1 - 3 - 7-trimethylxanthine
Bitter
Polyphenols

27. What happens to chlorophyll on heating?
Pheophytin forms
Browning of freshly cut surfaces of fruits and vegetables.
Onions ( or leeks)
Ammonia - Water - Carbon Dioxide

28. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
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
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Orange Juice
DNA transferred by cell to cell contact (bacterial sex).

29. What is the structural difference between chlorophyll and pheophytia?
pH 3-5
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Fatty Acid and Alcohol
Pheophytia does not have magnesium in porphyrin ring.

30. How many polypeptide chains make up an antibody?
Racemic Mixture
pH below positive charge; pH at no charge; pH above negative charge
Anthocyanins
Four

31. Contains the lowest content of water
Whole Milk
Thamautin
2.5
Emulsoids

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

33. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Yellow
Thermus Aqauticus
Anomeric
Non-protein nitrogen

34. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Water
Phenylketonuria

35. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Fat Oxidation
Ascorbic Acid and Citric Acid
Arachidonic Acid

36. What is the enzyme that softens tomatoes?
Erythorbic Acid
Pectin Esterase
.05
Lysine - Arginine - and Histidine

37. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Thermus Aqauticus
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
.05
Pectin methyl esterase or galacturonase

38. What is acid proteolysis?
Degradation of protein and production of acid from sugar at the same time.
Whole Milk
Speed of Light
Sweet - Salty - Sour - and Bitter

39. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Anomeric
V=IR and P=VI or I x I x are
Yellow
Acsulfame-K - Saccharin - Cyclamate - Aspartame

40. At low water activity What is the main deteriorative concern?
Oil in Water
Browning of freshly cut surfaces of fruits and vegetables.
Sucrose
Lipid oxidation

41. What are the fructose contents in commercial HFCS products.
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.
45% - 52% - 90%
Onions ( or leeks)

42. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Onions ( or leeks)
Lipase
Primary butyric acid also caproic acid.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

43. What are two common reducing agents that break disulfide bonds in proteins?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Phenylketonuria
RNA transcribed to DNA
Pectin Esterase

44. Is a disaccharide
Sucrose
Blue pigment in flowers
Speed of Light
Bitter

45. Name 3 chemical agents capable of denaturing proteins.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Phenylketonuria
Polyphenoloxidase

46. What are the only phenols approved for use in the microbiological preservation of foods?
Milk
A concentrate of microfibrillar proteins of fish muscle.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Parabens

47. What is the major color compound in tomatoes?
Nucleation or crystal formation and crystal growth.
Erythorbic Acid
Lycopenes
Onions ( or leeks)

48. What are proteins which are soluble in 50-80% ethanol known as?
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.
Water
Osmosis
Prolamines

49. What is the enzyme responsible for browning in apples and lettuce?
Carmelization and Maillard
Polyphenols
NaCl (it dissociated to a 2M solution)
Polyphenol Oxidase

50. Does kosmotrophil ion discourage water structure?
No
Phenophylin
Monosodium Glutamate
Capsaicin