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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. What are two common reducing agents that break disulfide bonds in proteins?
Anomeric
Water
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Thamautin

2. Is a disaccharide
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Sucrose
Pheophytia does not have magnesium in porphyrin ring.
Bright green

3. How many polypeptide chains make up an antibody?
A concentrate of microfibrillar proteins of fish muscle.
Four
Carrageenan
Fatty Acid (Ester linked) to Fatty Alcohol

4. What are colloids that are stabilized by a layer of solvation called?
Emulsoids
Glycosides of anthocyanidins
Whole Milk
Lipase

5. What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Aspartic Acid and Phenylalanine
Capsaicin
Glycosides of anthocyanidins

6. Will lipid oxidation be higher at a water activity of .05 or .5?
Thamautin
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Fructose
.05

7. Name one way foam stability can be assessed.
.05 M HCL
Non-protein nitrogen
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.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

8. What is Carboxy-methyl cellulose often used for?
Degradation of protein and production of acid from sugar at the same time.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Thickener in foods
ERH=100 x Aw

9. Name three nonpolar polar - and charged amino acids.
Pheophytin forms
Covalent (strongest) and Hydrophobic (Weakest)
Daminozide
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

10. What is acid proteolysis?
Degradation of protein and production of acid from sugar at the same time.
Pectin methylesterase & polygalacturonase
Osmosis
Phenophylin

11. Name a commonly used household chemical leavening agent and the gas it generates.
Whole Milk
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Sodium bicarbonate generates CO2
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.

12. What does MSG stand for?
NaCl (it dissociated to a 2M solution)
Monosodium Glutamate
Thermus Aqauticus
Yes

13. Which two amino acids is the aspartame derived from?
Fat Oxidation
Troponins and Tropomyosin
Aspartic Acid and Phenylalanine
Anomeric

14. What is the winterization process for an oil?
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Chitin
Blue pigment in flowers
Aspartic Acid and Phenylalanine

15. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
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
Acetoin
Monosodium Glutamate
Polyphenoloxidase

16. What is the Peroxide Value a measure of?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Fat Oxidation
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

17. What happens to chlorophyll on heating?
Water
Primary butyric acid also caproic acid.
Pheophytin forms
Negative log of the hydrogen concentration (mol/l).

18. How can a molecular weight of protein - DNA - and RNA be determined?
Lipase
Cis
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
pH below positive charge; pH at no charge; pH above negative charge

19. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Ammonia - Water - Carbon Dioxide
Lycopenes
Water
Bitter

20. What are 3 mesomorphic structures associated with lipids in the liquid state?
Lipid oxidation
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Lamellar; Hexagonal I - II; Cubic
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

21. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Pectins
Anthocyanins
Linoleic Acid
NaCl (it dissociated to a 2M solution)

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

23. Name one way foam stability can be assessed.
Glycosides of anthocyanidins
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.
Water
Aspartic Acid and Phenylalanine

24. What is the name of the degradation compound of chlorophyll?
Phenophylin
Yellow
A concentrate of microfibrillar proteins of fish muscle.
Daminozide

25. 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?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Racemic Mixture
Thickener in foods
Two aldehydes

26. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Phenophylin
Troponins and Tropomyosin
Arachidonic Acid
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

27. What metabolic end product does the Voges-Proskauer test detect?
Acetoin
Ascorbic Acid and Citric Acid
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Daminozide

28. How do sodium chloride and sucrose affect foam stability?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Sodium chloride reduces foam stability and sucrose improves foam stability.
2.5
Pectins

29. What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
Lysine - Arginine - and Histidine
Phenophylin
Chlocophyllide does not have a phytoltail

30. What is the major color compound in tomatoes?
Lycopenes
It explodes
Phenophylin
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

31. Name 3 factors influencing the rate of lipid oxidation in foods.
Prolamines
Phenylketonuria
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Gliadins and Glutenins

32. Name 3 physical agents capable of denaturing proteins.
Cis
Milk
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

33. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Gossypol (it is removed during the oil refining process)
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Nucleation or crystal formation and crystal growth.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

34. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
Bitter
Milk
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
They act as catalysts - speeding the polymerization of acrylamide.

35. Which of the following examples of browning is enzymatic in nature? 1. Browning of sugars as a result of heating 2. Browning of freshly cut surfaces of fruits and vegetables 3. Browning of bread during toasting 4. Browning of potato chips
Nucleation or crystal formation and crystal growth.
Browning of freshly cut surfaces of fruits and vegetables.
Pectin Esterase
Yes

36. What is Carboxy-methyl cellulose often used for?
Prolamines
Thickener in foods
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
It explodes

37. Is a disaccharide
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
Sucrose
Pheophytin forms
Sodium chloride reduces foam stability and sucrose improves foam stability.

38. Name 3 chemical agents capable of denaturing proteins.
Initiation - Propagation - Termination
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Arachidonic Acid
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

39. What toxic pigment is found in cottonseed endosperm?
Gossypol (it is removed during the oil refining process)
Anomeric
ERH=100 x Aw
Whole Milk

40. How can a molecular weight of protein - DNA - and RNA be determined?
Pectin Esterase - Polygalacturonase - Pectin Layase
Blue pigment in flowers
Thamautin
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

41. What are proteins which are soluble in 50-80% ethanol known as?
20 carbons and 4 double bonds
Osmosis
Sucrose
Prolamines

42. Does kosmotrophil ion discourage water structure?
45% - 52% - 90%
Pheophytia does not have magnesium in porphyrin ring.
Speed of Light
No

43. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Carrageenan
Phenophylin
Chlocophyllide does not have a phytoltail
Phenylketonuria

44. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Polyphenol Oxidase
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

45. Name two enzymes that are involved in softening fruits.
Initiation - Propagation - and Termination
Bitter
Pectin Esterase - Polygalacturonase - Pectin Layase
Polyphenol Oxidase

46. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Pectin methyl esterase or galacturonase
Gossypol (it is removed during the oil refining process)
Cis
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

47. What compounds oxidize to form brown color in fruits and vegetables?
Polyphenols
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
V=IR and P=VI or I x I x are
Tryptophan

48. Name the two components that comprise the relaxing factor in muscle fibers.
Orange Juice
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Troponins and Tropomyosin
Acsulfame-K - Saccharin - Cyclamate - Aspartame

49. What does the 'c' stand for in the equation E=mc2?
Pheophytin forms
Pheophytia does not have magnesium in porphyrin ring.
Gliadins and Glutenins
Speed of Light

50. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Sodium chloride reduces foam stability and sucrose improves foam stability.
ERH=100 x Aw
Blue pigment in flowers