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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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1. What are the three stages of oxidative rancidity?
Lipid oxidation
Lycopenes
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Initiation - Propagation - and Termination

2. What two common compounds are used together as an antioxidative system?
Tryptophan
Gossypol (it is removed during the oil refining process)
Ascorbic Acid and Citric Acid
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.

3. During freezing What are the two stages in the crystallization process?
Fructose
Olive Green
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Nucleation or crystal formation and crystal growth.

4. 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.
D: None of the above
Bright green
Nucleation or crystal formation and crystal growth.

5. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Phenophylin
NaCl (it dissociated to a 2M solution)
Fatty Acid (Ester linked) to Fatty Alcohol
Blue pigment in flowers

6. What effect would the addition of sodium bicarbonate have to chocolate?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
pH below positive charge; pH at no charge; pH above negative charge
Prolamines
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

7. How do sodium chloride and sucrose affect foam stability?
Sodium chloride reduces foam stability and sucrose improves foam stability.
2.5
Orange Juice
They act as catalysts - speeding the polymerization of acrylamide.

8. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
14
Glycosides of anthocyanidins
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

9. What is an isomer that is cheaper than Vitamin C?
Prolamines
Erythorbic Acid
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.

10. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Pectin Esterase - Polygalacturonase - Pectin Layase
Plasmids

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

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12. What is the name of the degradation compound of chlorophyll?
Pheophytia does not have magnesium in porphyrin ring.
Phenophylin
Yellow
Sodium bicarbonate generates CO2

13. What are the three stages of oxidative rancidity?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Initiation - Propagation - and Termination
Whole Milk
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

14. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Sodium chloride reduces foam stability and sucrose improves foam stability.
pH below positive charge; pH at no charge; pH above negative charge
Water
Degradation of protein and production of acid from sugar at the same time.

15. What is the fundamental driving of electrophoresis?
Chitin
V=IR and P=VI or I x I x are
The speed of a molecule is proportional to the surrounding voltage gradient.
Racemic Mixture

16. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Lamellar; Hexagonal I - II; Cubic
Bitter
Speed of Light
Polyphenoloxidase

17. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Water
Lipase
Non-protein nitrogen
Polyphenol Oxidase

18. What metabolic end product does the Voges-Proskauer test detect?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Acetoin
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Covalent (strongest) and Hydrophobic (Weakest)

19. What happens to chlorophyll on heating?
Water
Polyphenol Oxidase
Pheophytin forms
Initiation - Propagation - and Termination

20. What are the four basic flavors perceived by the tongue?
Sweet - Salty - Sour - and Bitter
Aspartic Acid and Phenylalanine
Ascorbic Acid and Citric Acid
Milk

21. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
Polyphenol Oxidase
Ammonia - Water - Carbon Dioxide
Pheophytin forms

22. What are proteins which are soluble in 50-80% ethanol known as?
Prolamines
Sweet - Salty - Sour - and Bitter
Fatty Acid and Alcohol
Cis

23. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Thermus Aqauticus
Four
Aspartic Acid and Phenylalanine
Bright green

24. Name two main gluten proteins.
Pheophytia does not have magnesium in porphyrin ring.
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Gliadins and Glutenins

25. What is the acid present in fish oil?
Yes
Phenophylin
Anthocyanins
Arachidonic Acid

26. What happens to a bottle of wine if before you bottle it you forget to put the stuff in it that prevents it from fermenting?
Lycopenes
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
It explodes
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

27. How many polypeptide chains make up an antibody?
No
An enzyme that converts hydrogen peroxide to water plus oxygen.
Four
Pheophytin forms

28. 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
D: None of the above
Browning of freshly cut surfaces of fruits and vegetables.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Aspartic Acid and Phenylalanine

29. What does the saponification value measure and how is it measured?
Carmelization and Maillard
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Ammonia - Water - Carbon Dioxide
Cis

30. Name three effects of protein denaturation.
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.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Bright green

31. Name one way foam stability can be assessed.
Ammonia - Water - Carbon Dioxide
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.
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.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

32. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
It explodes
Daminozide
Oil in Water
Whole Milk

33. What is the enzyme that softens tomatoes?
A concentrate of microfibrillar proteins of fish muscle.
Initiation - Propagation - and Termination
Sodium bicarbonate generates CO2
Pectin Esterase

34. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Water
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Polyphenoloxidase
Glycosides of anthocyanidins

35. Are sorbitol and mannitol sweet?
Acetoin
Yes
Thermus Aqauticus
45% - 52% - 90%

36. How do sodium chloride and sucrose affect foam stability?
Lamellar; Hexagonal I - II; Cubic
Sodium chloride reduces foam stability and sucrose improves foam stability.
Yes
Fatty Acid (Ester linked) to Fatty Alcohol

37. How does HPLC differ from FPLC?
45% - 52% - 90%
Erythorbic Acid
Gliadins and Glutenins
HPLC has higher pressure than FPLC

38. What are the fructose contents in commercial HFCS products.
Lipase
Whole Milk
Water
45% - 52% - 90%

39. Name the most common functional property of phospholipids in food systems.
Emulsification
Ascorbic Acid and Citric Acid
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

40. What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
HPLC has higher pressure than FPLC
Lipase
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.

41. What two common compounds are used together as an antioxidative system?
Aspartic Acid and Phenylalanine
Ascorbic Acid and Citric Acid
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

42. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Phenophylin
Pectins
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

43. In the enzyme Taq Polymerase What does Taq stand for?
Thermus Aqauticus
Plasmids
Daminozide
pH 3-5

44. What is a polymorphism?
2.5
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Milk

45. Name a commonly used household chemical leavening agent and the gas it generates.
It explodes
Sodium bicarbonate generates CO2
Non-protein nitrogen
Emulsification

46. Is a disaccharide
Chitin
Polyphenol Oxidase
Nucleation or crystal formation and crystal growth.
Sucrose

47. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
Polyphenol Oxidase
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.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

48. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Polyphenols
Thermus Aqauticus
Carrageenan
Initiation - Propagation - Termination

49. How does ERH relate to water activity?
ERH=100 x Aw
No
Anomeric
pH below positive charge; pH at no charge; pH above negative charge

50. How does ERH relate to water activity?
Cis
Aspartic Acid and Phenylalanine
ERH=100 x Aw
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.