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Food Chemistry

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Answer 50 questions in 15 minutes.
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1. 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.
Aspartic Acid and Phenylalanine
Bitter
Osmosis

2. What compounds oxidize to form brown color in fruits and vegetables?
Emulsification
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Polyphenols
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

3. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Polyphenoloxidase
Daminozide
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.

4. How does HPLC differ from FPLC?
Cis
NaCl (it dissociated to a 2M solution)
Initiation - Propagation - Termination
HPLC has higher pressure than FPLC

5. 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?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Pectins
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
.05 M HCL

6. Name 3 physical agents capable of denaturing proteins.
Pectins
Monosodium Glutamate
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
The speed of a molecule is proportional to the surrounding voltage gradient.

7. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
NaCl (it dissociated to a 2M solution)
Pectin methyl esterase or galacturonase
Glycosides of anthocyanidins

8. What is the chemical nature of anthocyanins?
Glycosides of anthocyanidins
Fat Oxidation
Thickener in foods
No

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

10. Name three factors useful in controlling enzyme activity.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
.05 M HCL
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.
Pectin Esterase

11. 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?
It explodes
.05 M HCL
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
45% - 52% - 90%

12. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
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.
2.5
Chitin

13. What are the primary secondary - tertiary - and quaternary structures?
Pheophytia does not have magnesium in porphyrin ring.
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.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Carrageenan

14. What two enzymes degrade pectic substances?
Cis
Pectin methylesterase & polygalacturonase
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Chitin

15. At low water activity What is the main deteriorative concern?
Lipid oxidation
Nucleation or crystal formation and crystal growth.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Water

16. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Whole Milk
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Racemic Mixture
NaCl (it dissociated to a 2M solution)

17. What is the fundamental driving of electrophoresis?
.05
Whole Milk
The speed of a molecule is proportional to the surrounding voltage gradient.
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.

18. Name three non-nutritive sweeteners approved for use in USA?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Lamellar; Hexagonal I - II; Cubic
Pectins
Gliadins and Glutenins

19. How is pH defined?
Negative log of the hydrogen concentration (mol/l).
Osmosis
Carrageenan
Pectin Esterase

20. At what pH is benzoic acid most effective?
Erythorbic Acid
The speed of a molecule is proportional to the surrounding voltage gradient.
pH 3-5
Yes

21. What is the enzyme responsible for browning in apples and lettuce?
Phenylketonuria
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
Anomeric
Polyphenol Oxidase

22. What is the Peroxide Value a measure of?
Initiation - Propagation - and Termination
Emulsoids
Primary butyric acid also caproic acid.
Fat Oxidation

23. What enzyme is most responsible for browning bananas?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Pectin Esterase
Polyphenol Oxidase
HPLC has higher pressure than FPLC

24. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Olive Green
Non-protein nitrogen
Ammonia - Water - Carbon Dioxide
14

25. What is the fundamental driving of electrophoresis?
Arachidonic Acid
The speed of a molecule is proportional to the surrounding voltage gradient.
Olive Green
Polyphenol Oxidase

26. What are the fructose contents in commercial HFCS products.
Negative log of the hydrogen concentration (mol/l).
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Bright green
45% - 52% - 90%

27. What does Acid Degree Value measure and how is it measured?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Prolamines
Polyphenols
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

28. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Lipid oxidation
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
RNA transcribed to DNA
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

29. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Pectins
Polyphenols
Yellow
Primary butyric acid also caproic acid.

30. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Nucleation or crystal formation and crystal growth.
Ascorbic Acid and Citric Acid
Bright green
Yes

31. Waxes are composed of what two basic chemical entities?
Pectin methylesterase & polygalacturonase
NaCl (it dissociated to a 2M solution)
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Fatty Acid (Ester linked) to Fatty Alcohol

32. How is pH defined?
Yellow
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Negative log of the hydrogen concentration (mol/l).
2.5

33. In the enzyme Taq Polymerase What does Taq stand for?
Gossypol (it is removed during the oil refining process)
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Thermus Aqauticus

34. Will lipid oxidation be higher at a water activity of .05 or .5?
.05
Polyphenols
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
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

35. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Onions ( or leeks)
Anthocyanins

36. Name a commonly used household chemical leavening agent and the gas it generates.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Erythorbic Acid
Sodium bicarbonate generates CO2

37. Name three nonpolar polar - and charged amino acids.
Capsaicin
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Chitin
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

38. What two common compounds are used together as an antioxidative system?
Ascorbic Acid and Citric Acid
Acetoin
Covalent (strongest) and Hydrophobic (Weakest)
Chlocophyllide does not have a phytoltail

39. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
Negative log of the hydrogen concentration (mol/l).
They act as catalysts - speeding the polymerization of acrylamide.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

40. Name two reasons why fats are hydrogenated.
Thermus Aqauticus
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Olive Green
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

41. In what food is butyric acid typically found?
Parabens
Milk
Prolamines
Anthocyanins

42. Which two amino acids is the aspartame derived from?
Browning of freshly cut surfaces of fruits and vegetables.
Aspartic Acid and Phenylalanine
Pectin Esterase
Prolamines

43. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Oil in Water
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Capsaicin
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

44. What are the primary secondary - tertiary - and quaternary structures?
pH 3-5
Daminozide
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
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.

45. Peptide bond formation results in the formation of what secondary compound?
Nucleation or crystal formation and crystal growth.
Water
Chlocophyllide does not have a phytoltail
Pectin Esterase - Polygalacturonase - Pectin Layase

46. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Browning of freshly cut surfaces of fruits and vegetables.
Aspartic Acid and Phenylalanine
Phenylketonuria
RNA transcribed to DNA

47. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
2.5
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Chitin
NaCl (it dissociated to a 2M solution)

48. What does MSG stand for?
Monosodium Glutamate
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
45% - 52% - 90%
Daminozide

49. Name the strongest biochemical bond and the weakest biochemical bond.
14
Lamellar; Hexagonal I - II; Cubic
Covalent (strongest) and Hydrophobic (Weakest)
HPLC has higher pressure than FPLC

50. Name three non-nutritive sweeteners approved for use in USA?
NaCl (it dissociated to a 2M solution)
Troponins and Tropomyosin
Polyphenols
Acsulfame-K - Saccharin - Cyclamate - Aspartame