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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. When heated ammonium bicarbonate decomposes to form what end products?
Carrageenan
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Osmosis
Ammonia - Water - Carbon Dioxide

2. What two enzymes degrade pectic substances?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Pectin methylesterase & polygalacturonase
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Whole Milk

3. Name three effects of protein denaturation.
1 - 3 - 7-trimethylxanthine
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

4. What are 3 mesomorphic structures associated with lipids in the liquid state?
Blue pigment in flowers
Pectin methylesterase & polygalacturonase
Lamellar; Hexagonal I - II; Cubic
1 - 3 - 7-trimethylxanthine

5. What are colloids that are stabilized by a layer of solvation called?
RNA transcribed to DNA
Ascorbic Acid and Citric Acid
Browning of freshly cut surfaces of fruits and vegetables.
Emulsoids

6. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Yellow
RNA transcribed to DNA
1 - 3 - 7-trimethylxanthine
Daminozide

7. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
NaCl (it dissociated to a 2M solution)
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.
Milk
Tryptophan

8. How many polypeptide chains make up an antibody?
Polyphenols
Four
Lysine - Arginine - and Histidine
V=IR and P=VI or I x I x are

9. What is the chemical nomenclature for caffeine?
Covalent (strongest) and Hydrophobic (Weakest)
1 - 3 - 7-trimethylxanthine
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin methylesterase & polygalacturonase

10. Name the strongest biochemical bond and the weakest biochemical bond.
Emulsoids
Covalent (strongest) and Hydrophobic (Weakest)
Plasmids
Onions ( or leeks)

11. Name two non-enzymatic browning reactions.
Osmosis
An enzyme that converts hydrogen peroxide to water plus oxygen.
Carmelization and Maillard
Pheophytin forms

12. 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?
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
1 - 3 - 7-trimethylxanthine
Polyphenoloxidase

13. What is a polymorphism?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
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
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

14. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Four
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Olive Green
Lysine - Arginine - and Histidine

15. What are two common reducing agents that break disulfide bonds in proteins?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Ascorbic Acid and Citric Acid
Thickener in foods
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

16. What is the structural difference between chlorophyll and chlocophyllide?
Non-protein nitrogen
Lycopenes
Chlocophyllide does not have a phytoltail
An enzyme that converts hydrogen peroxide to water plus oxygen.

17. Alar is the trade name for what chemical compound?
Daminozide
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
It explodes
Initiation - Propagation - and Termination

18. What charge will a protein have when the pH of its solution is below at - and above its pKa?
NaCl (it dissociated to a 2M solution)
pH below positive charge; pH at no charge; pH above negative charge
Carrageenan
Lamellar; Hexagonal I - II; Cubic

19. What is the Peroxide Value a measure of?
Gossypol (it is removed during the oil refining process)
V=IR and P=VI or I x I x are
Fat Oxidation
Pheophytia does not have magnesium in porphyrin ring.

20. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Bright green
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Two aldehydes

21. What does MSG stand for?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Sodium bicarbonate generates CO2
Monosodium Glutamate
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

22. Name one way foam stability can be assessed.
Pheophytin forms
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.
D: None of the above
Acsulfame-K - Saccharin - Cyclamate - Aspartame

23. Name 3 factors influencing the consistency of commercial fats.
Emulsification
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Orange Juice
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

24. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Non-protein nitrogen
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Water
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

25. Name two enzymes that are involved in softening fruits.
Pectin Esterase - Polygalacturonase - Pectin Layase
It explodes
Plasmids
Carrageenan

26. What are the limiting amino acids in corn - potato - and green peas?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Ascorbic Acid and Citric Acid
Onions ( or leeks)

27. Name three non-nutritive sweeteners approved for use in USA?
Two aldehydes
Pectin Esterase - Polygalacturonase - Pectin Layase
Racemic Mixture
Acsulfame-K - Saccharin - Cyclamate - Aspartame

28. How is pH defined?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Parabens
Negative log of the hydrogen concentration (mol/l).
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.

29. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
An enzyme that converts hydrogen peroxide to water plus oxygen.
V=IR and P=VI or I x I x are
Tryptophan
Whole Milk

30. Name three nonpolar polar - and charged amino acids.
Yellow
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Carrageenan
Phenylketonuria

31. 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
ERH=100 x Aw
DNA transferred by cell to cell contact (bacterial sex).
Negative log of the hydrogen concentration (mol/l).
D: None of the above

32. What is Carboxy-methyl cellulose often used for?
Thickener in foods
Troponins and Tropomyosin
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

33. What compounds oxidize to form brown color in fruits and vegetables?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Polyphenols
ERH=100 x Aw
Pectin methylesterase & polygalacturonase

34. Name two reasons why fats are hydrogenated.
Pectin methyl esterase or galacturonase
Troponins and Tropomyosin
Fructose
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

35. Does kosmotrophil ion discourage water structure?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
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.
D: None of the above
No

36. What is the structural difference between chlorophyll and pheophytia?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Pheophytia does not have magnesium in porphyrin ring.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
DNA transferred by cell to cell contact (bacterial sex).

37. Name two main gluten proteins.
Orange Juice
Negative log of the hydrogen concentration (mol/l).
Lipid oxidation
Gliadins and Glutenins

38. What are the four basic flavors perceived by the tongue?
Gliadins and Glutenins
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Sweet - Salty - Sour - and Bitter
Pectin Esterase

39. 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?
Thickener in foods
Sodium chloride reduces foam stability and sucrose improves foam stability.
Initiation - Propagation - Termination
.05 M HCL

40. What are soluble polymers of anhydro-galacturonic acid and its esters called?
pH below positive charge; pH at no charge; pH above negative charge
Tryptophan
Pectins
Pectin Esterase - Polygalacturonase - Pectin Layase

41. What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
Emulsoids
Gossypol (it is removed during the oil refining process)
Anomeric

42. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
Capsaicin
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
Fatty Acid and Alcohol
Browning of freshly cut surfaces of fruits and vegetables.

43. What is an isomer that is cheaper than Vitamin C?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Bright green
HPLC has higher pressure than FPLC
Erythorbic Acid

44. What effect would the addition of sodium bicarbonate have to chocolate?
Fatty Acid (Ester linked) to Fatty Alcohol
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.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

45. What enzyme is most responsible for browning bananas?
HPLC has higher pressure than FPLC
Polyphenol Oxidase
Fatty Acid and Alcohol
Fatty Acid (Ester linked) to Fatty Alcohol

46. What two common compounds are used together as an antioxidative system?
Ascorbic Acid and Citric Acid
20 carbons and 4 double bonds
Browning of freshly cut surfaces of fruits and vegetables.
Yellow

47. At what pH is benzoic acid most effective?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
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
Emulsification
pH 3-5

48. In the enzyme Taq Polymerase What does Taq stand for?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Chitin
Arachidonic Acid
Thermus Aqauticus

49. Alar is the trade name for what chemical compound?
Arachidonic Acid
Two aldehydes
Troponins and Tropomyosin
Daminozide

50. How many carbon atoms are there in the fatty acid myristic acid?
Pheophytin forms
14
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.
Water