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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. Give one word for a carbon atom involved in hemiacetal or acetal formation.
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.
Daminozide
Anomeric
Capsaicin

2. What are the three stages of oxidative rancidity?
Initiation - Propagation - and Termination
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Carrageenan
Nucleation or crystal formation and crystal growth.

3. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
RNA transcribed to DNA
Sucrose
Prolamines
Carmelization and Maillard

4. Name one way foam stability can be assessed.
NaCl (it dissociated to a 2M solution)
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
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.
NaCl (it dissociated to a 2M solution)

5. Name the strongest biochemical bond and the weakest biochemical bond.
pH 3-5
Browning of freshly cut surfaces of fruits and vegetables.
Aspartic Acid and Phenylalanine
Covalent (strongest) and Hydrophobic (Weakest)

6. What is the geometric configuration of double bonds in most natural fatty acids?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
An enzyme that converts hydrogen peroxide to water plus oxygen.
Cis

7. How many polypeptide chains make up an antibody?
pH 3-5
Pectins
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Four

8. At what pH is benzoic acid most effective?
pH 3-5
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Speed of Light
Emulsification

9. At what pH is benzoic acid most effective?
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.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Primary butyric acid also caproic acid.
pH 3-5

10. What does MSG stand for?
Monosodium Glutamate
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.
Troponins and Tropomyosin
Phenophylin

11. What is an isomer that is cheaper than Vitamin C?
Lipid oxidation
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Glycosides of anthocyanidins
Erythorbic Acid

12. What metabolic end product does the Voges-Proskauer test detect?
Thamautin
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Acetoin

13. Name three nonpolar polar - and charged amino acids.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Lamellar; Hexagonal I - II; Cubic
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
V=IR and P=VI or I x I x are

14. Is a disaccharide
Sucrose
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

15. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Thickener in foods
14
Phenylketonuria
Chitin

16. What is acid proteolysis?
Troponins and Tropomyosin
Degradation of protein and production of acid from sugar at the same time.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Pectin Esterase

17. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Speed of Light
No
Tryptophan
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

18. Name 3 factors influencing the consistency of commercial fats.
Sodium bicarbonate generates CO2
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Non-protein nitrogen
Bitter

19. What is the protein efficiency ratio (PER) of casein?
Thickener in foods
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Aspartic Acid and Phenylalanine
2.5

20. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Linoleic Acid
Emulsoids
Polyphenol Oxidase
Sucrose

21. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Thickener in foods
An enzyme that converts hydrogen peroxide to water plus oxygen.
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.
Carrageenan

22. How many polypeptide chains make up an antibody?
Polyphenol Oxidase
Four
Aspartic Acid and Phenylalanine
Bitter

23. What are two common reducing agents that break disulfide bonds in proteins?
Anthocyanins
Bright green
A concentrate of microfibrillar proteins of fish muscle.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

24. What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
2.5
Linoleic Acid

25. What does the iodine value measure and how is it measured?
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Thermus Aqauticus
ERH=100 x Aw
Fatty Acid (Ester linked) to Fatty Alcohol

26. What are 3 mesomorphic structures associated with lipids in the liquid state?
Initiation - Propagation - Termination
Lamellar; Hexagonal I - II; Cubic
D: None of the above
Onions ( or leeks)

27. What is the acid present in fish oil?
Arachidonic Acid
Sucrose
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
pH below positive charge; pH at no charge; pH above negative charge

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

29. What are colloids that are stabilized by a layer of solvation called?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
2.5
An enzyme that converts hydrogen peroxide to water plus oxygen.
Emulsoids

30. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Thermus Aqauticus
Racemic Mixture

31. What is the geometric configuration of double bonds in most natural fatty acids?
D: None of the above
Cis
Pectin Esterase - Polygalacturonase - Pectin Layase
NaCl (it dissociated to a 2M solution)

32. What are the limiting amino acids in corn - potato - and green peas?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Daminozide
Sweet - Salty - Sour - and Bitter
DNA transferred by cell to cell contact (bacterial sex).

33. What does the iodine value measure and how is it measured?
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Four
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Oil in Water

34. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Chlocophyllide does not have a phytoltail
Bitter
Glycosides of anthocyanidins
Initiation - Propagation - and Termination

35. What does MSG stand for?
Polyphenol Oxidase
Ammonia - Water - Carbon Dioxide
.05
Monosodium Glutamate

36. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Degradation of protein and production of acid from sugar at the same time.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
pH below positive charge; pH at no charge; pH above negative charge
Glycosides of anthocyanidins

37. What is the enzyme that softens tomatoes?
Pheophytia does not have magnesium in porphyrin ring.
Initiation - Propagation - Termination
Pectin Esterase
Thermus Aqauticus

38. How is pH defined?
.05 M HCL
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.
Negative log of the hydrogen concentration (mol/l).
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.

39. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Orange Juice
Sodium bicarbonate generates CO2
Chitin
Pectin Esterase

40. How many carbon atoms and how many double bonds are there in arachidonic acid?
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Chitin
Erythorbic Acid
20 carbons and 4 double bonds

41. 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?
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
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)
Bitter

42. How can a molecular weight of protein - DNA - and RNA be determined?
Polyphenoloxidase
Yellow
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Anomeric

43. Define molarity molality - and normality.
Lycopenes
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Phenophylin
Whole Milk

44. At low water activity What is the main deteriorative concern?
Lipid oxidation
Thickener in foods
D: None of the above
Negative log of the hydrogen concentration (mol/l).

45. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Fatty Acid (Ester linked) to Fatty Alcohol
Polyphenoloxidase
Pheophytia does not have magnesium in porphyrin ring.
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

46. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
Initiation - Propagation - and Termination
Ammonia - Water - Carbon Dioxide
They act as catalysts - speeding the polymerization of acrylamide.
Daminozide

47. What are proteins which are soluble in 50-80% ethanol known as?
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
The speed of a molecule is proportional to the surrounding voltage gradient.
Prolamines
Initiation - Propagation - Termination

48. Name two non-enzymatic browning reactions.
Carmelization and Maillard
Polyphenols
Anthocyanins
Blue pigment in flowers

49. Name 4 advantages of using enzymes in food processing.
Negative log of the hydrogen concentration (mol/l).
Emulsification
Polyphenol Oxidase
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

50. When heated ammonium bicarbonate decomposes to form what end products?
Daminozide
Ammonia - Water - Carbon Dioxide
Browning of freshly cut surfaces of fruits and vegetables.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.