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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 happens to chlorophyll on heating?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Onions ( or leeks)
Carrageenan
Pheophytin forms

2. What is the name of the degradation compound of chlorophyll?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Phenophylin
Linoleic Acid
Lipase

3. Define molarity molality - and normality.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Initiation - Propagation - and Termination
The speed of a molecule is proportional to the surrounding voltage gradient.

4. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Polyphenoloxidase
They act as catalysts - speeding the polymerization of acrylamide.
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

5. How many polypeptide chains make up an antibody?
Four
Lipase
Phenophylin
Oil in Water

6. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
The speed of a molecule is proportional to the surrounding voltage gradient.
Daminozide
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Pectin methyl esterase or galacturonase

7. What two common compounds are used together as an antioxidative system?
20 carbons and 4 double bonds
Glycosides of anthocyanidins
Ascorbic Acid and Citric Acid
Polyphenols

8. What ketohexose is most significant to food chemists?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Water
Lamellar; Hexagonal I - II; Cubic
Fructose

9. How does HPLC differ from FPLC?
Chlocophyllide does not have a phytoltail
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
HPLC has higher pressure than FPLC
Yes

10. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Pheophytin forms
Sucrose
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
pH below positive charge; pH at no charge; pH above negative charge

11. What are colloids that are stabilized by a layer of solvation called?
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.
Pectin methylesterase & polygalacturonase
Emulsification

12. How can a molecular weight of protein - DNA - and RNA be determined?
Initiation - Propagation - and Termination
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Negative log of the hydrogen concentration (mol/l).

13. What is Carboxy-methyl cellulose often used for?
Pheophytin forms
Lipid oxidation
Thickener in foods
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

14. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Chlocophyllide does not have a phytoltail
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Yellow

15. What does the saponification value measure and how is it measured?
Polyphenol Oxidase
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Pectin methyl esterase or galacturonase
Water

16. What is Ohm's Law and What is Power Equation?
Chitin
V=IR and P=VI or I x I x are
Browning of freshly cut surfaces of fruits and vegetables.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

17. Name a commonly used household chemical leavening agent and the gas it generates.
Osmosis
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Sodium bicarbonate generates CO2
Thickener in foods

18. What is the structural difference between chlorophyll and chlocophyllide?
Lycopenes
Yes
Chlocophyllide does not have a phytoltail
Fatty Acid and Alcohol

19. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Ammonia - Water - Carbon Dioxide
pH 3-5

20. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Phenylketonuria
RNA transcribed to DNA
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
Degradation of protein and production of acid from sugar at the same time.

21. What is the fundamental driving of electrophoresis?
Water
The speed of a molecule is proportional to the surrounding voltage gradient.
Polyphenol Oxidase
NaCl (it dissociated to a 2M solution)

22. What does the acronym NPN stand for?
20 carbons and 4 double bonds
Fructose
Non-protein nitrogen
Pheophytin forms

23. What metabolic end product does the Voges-Proskauer test detect?
Daminozide
Ascorbic Acid and Citric Acid
Acetoin
D: None of the above

24. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
The speed of a molecule is proportional to the surrounding voltage gradient.
.05
Phenylketonuria

25. What is the name given to a mixture of equal parts of Darel Lisomers?
Degradation of protein and production of acid from sugar at the same time.
1 - 3 - 7-trimethylxanthine
Chlocophyllide does not have a phytoltail
Racemic Mixture

26. What is the protein efficiency ratio (PER) of casein?
Four
NaCl (it dissociated to a 2M solution)
2.5
Orange Juice

27. What two types of compounds are joined with an ester bond to make a wax?
20 carbons and 4 double bonds
Linoleic Acid
Fatty Acid and Alcohol
Pectin methyl esterase or galacturonase

28. Name three non-nutritive sweeteners approved for use in USA?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Monosodium Glutamate
Primary butyric acid also caproic acid.
NaCl (it dissociated to a 2M solution)

29. What is catalase?
Whole Milk
HPLC has higher pressure than FPLC
An enzyme that converts hydrogen peroxide to water plus oxygen.
Osmosis

30. Name three factors useful in controlling enzyme activity.
Ascorbic Acid and Citric Acid
Emulsoids
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
They act as catalysts - speeding the polymerization of acrylamide.

31. What is the major color compound in tomatoes?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Lycopenes
Thickener in foods
.05

32. What does MSG stand for?
It explodes
Monosodium Glutamate
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Sodium chloride reduces foam stability and sucrose improves foam stability.

33. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Parabens
Oil in Water
Blue pigment in flowers

34. What is Carboxy-methyl cellulose often used for?
Yes
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Thickener in foods
Acsulfame-K - Saccharin - Cyclamate - Aspartame

35. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
A concentrate of microfibrillar proteins of fish muscle.
Bitter
Pectin Esterase - Polygalacturonase - Pectin Layase
Anomeric

36. What two enzymes degrade pectic substances?
Fructose
Carmelization and Maillard
Pectin methylesterase & polygalacturonase
It explodes

37. What are the primary secondary - tertiary - and quaternary structures?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
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.
Water
Initiation - Propagation - and Termination

38. What does HLB stand for and What does a high and low HLB value indicate?
Racemic Mixture
Thamautin
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.
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. 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?
Polyphenoloxidase
Negative log of the hydrogen concentration (mol/l).
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Phenylketonuria

40. Name the most common functional property of phospholipids in food systems.
Emulsification
Olive Green
Polyphenol Oxidase
Daminozide

41. What toxic pigment is found in cottonseed endosperm?
Polyphenols
Orange Juice
Polyphenoloxidase
Gossypol (it is removed during the oil refining process)

42. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Plasmids
Aspartic Acid and Phenylalanine
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
45% - 52% - 90%

43. Name two main gluten proteins.
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
Cis
Gliadins and Glutenins
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

44. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Bitter
Polyphenoloxidase
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.
Fat Oxidation

45. Name 3 factors influencing the rate of lipid oxidation in foods.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Two aldehydes
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Bright green

46. Name the two components that comprise the relaxing factor in muscle fibers.
2.5
Lamellar; Hexagonal I - II; Cubic
Troponins and Tropomyosin
pH 3-5

47. Name three effects of protein denaturation.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Initiation - Propagation - and Termination
Plasmids
Lipase

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

49. Name 3 factors influencing the consistency of commercial fats.
Linoleic Acid
Polyphenoloxidase
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Sodium bicarbonate generates CO2

50. What is the main class of color compounds found in raspberries?
Anthocyanins
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.
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.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.