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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. How does HPLC differ from FPLC?
HPLC has higher pressure than FPLC
Arachidonic Acid
D: None of the above
Glycosides of anthocyanidins

2. What are the three main steps in the autooxidation of lipids?
A concentrate of microfibrillar proteins of fish muscle.
Initiation - Propagation - Termination
Gliadins and Glutenins
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

3. Name three nonpolar polar - and charged amino acids.
Ammonia - Water - Carbon Dioxide
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Bitter
Acetoin

4. What happens to chlorophyll on heating?
Yellow
Four
Sweet - Salty - Sour - and Bitter
Pheophytin forms

5. What is Carboxy-methyl cellulose often used for?
Ascorbic Acid and Citric Acid
Thickener in foods
No
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

6. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Yellow
V=IR and P=VI or I x I x are
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.

7. How many polypeptide chains make up an antibody?
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Four
Bright green
Bitter

8. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Emulsification
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Daminozide
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

9. Alar is the trade name for what chemical compound?
Lysine - Arginine - and Histidine
Daminozide
Whole Milk
Orange Juice

10. When heated ammonium bicarbonate decomposes to form what end products?
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.
Ammonia - Water - Carbon Dioxide
Pectin methylesterase & polygalacturonase

11. Name 3 factors influencing the rate of lipid oxidation in foods.
No
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Tryptophan
Negative log of the hydrogen concentration (mol/l).

12. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Pheophytia does not have magnesium in porphyrin ring.
Olive Green
No

13. Name the strongest biochemical bond and the weakest biochemical bond.
Fat Oxidation
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
D: None of the above
Covalent (strongest) and Hydrophobic (Weakest)

14. 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?
14
It explodes
Oil in Water
Lycopenes

15. Name 5 proteins with good foaming properties.
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.
Carmelization and Maillard
Polyphenols
pH 3-5

16. In what food is butyric acid typically found?
They act as catalysts - speeding the polymerization of acrylamide.
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
Milk
20 carbons and 4 double bonds

17. 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?
Erythorbic Acid
.05 M HCL
They act as catalysts - speeding the polymerization of acrylamide.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

18. What are colloids that are stabilized by a layer of solvation called?
Emulsoids
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Anomeric
Milk

19. Alar is the trade name for what chemical compound?
.05 M HCL
Whole Milk
Daminozide
Yellow

20. Will lipid oxidation be higher at a water activity of .05 or .5?
Daminozide
.05
An enzyme that converts hydrogen peroxide to water plus oxygen.
Linoleic Acid

21. How do sodium chloride and sucrose affect foam stability?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Monosodium Glutamate
Carmelization and Maillard

22. How is pH defined?
Negative log of the hydrogen concentration (mol/l).
Lamellar; Hexagonal I - II; Cubic
NaCl (it dissociated to a 2M solution)
Primary butyric acid also caproic acid.

23. What ketohexose is most significant to food chemists?
pH below positive charge; pH at no charge; pH above negative charge
Arachidonic Acid
Orange Juice
Fructose

24. Name the most common functional property of phospholipids in food systems.
Phenophylin
14
Pheophytin forms
Emulsification

25. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Linoleic Acid
Yes
Non-protein nitrogen
Covalent (strongest) and Hydrophobic (Weakest)

26. What are 3 mesomorphic structures associated with lipids in the liquid state?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
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.
Lamellar; Hexagonal I - II; Cubic
Yes

27. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
Sodium chloride reduces foam stability and sucrose improves foam stability.
Non-protein nitrogen
Emulsoids

28. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Emulsification
Anomeric
Bitter
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

29. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Prolamines
Tryptophan
Thamautin
Pectin Esterase

30. How many polypeptide chains make up an antibody?
Degradation of protein and production of acid from sugar at the same time.
Carrageenan
Four
They act as catalysts - speeding the polymerization of acrylamide.

31. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
They act as catalysts - speeding the polymerization of acrylamide.
Troponins and Tropomyosin
Onions ( or leeks)
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

32. What two types of compounds are joined with an ester bond to make a wax?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Fatty Acid and Alcohol
Acetoin
RNA transcribed to DNA

33. Name 4 advantages of using enzymes in food processing.
Phenophylin
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.
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
Acetoin

34. Name two enzymes that are involved in softening fruits.
Pectin Esterase - Polygalacturonase - Pectin Layase
Bitter
Fructose
Two aldehydes

35. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Oil in Water
Pectin methyl esterase or galacturonase
NaCl (it dissociated to a 2M solution)

36. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Sweet - Salty - Sour - and Bitter
pH below positive charge; pH at no charge; pH above negative charge
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Covalent (strongest) and Hydrophobic (Weakest)

37. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Anomeric
Fat Oxidation
Yellow
Monosodium Glutamate

38. What is the chemical nature of anthocyanins?
Glycosides of anthocyanidins
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Yellow
They act as catalysts - speeding the polymerization of acrylamide.

39. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Whole Milk
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Capsaicin

40. What metabolic end product does the Voges-Proskauer test detect?
pH below positive charge; pH at no charge; pH above negative charge
Lipase
Acetoin
Pheophytin forms

41. What is the chemical nomenclature for caffeine?
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
1 - 3 - 7-trimethylxanthine
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Lamellar; Hexagonal I - II; Cubic

42. What is a polymorphism?
Pectin Esterase - Polygalacturonase - Pectin Layase
Yes
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Non-protein nitrogen

43. Name two main gluten proteins.
Gliadins and Glutenins
Thickener in foods
A concentrate of microfibrillar proteins of fish muscle.
Pectins

44. What are the limiting amino acids in corn - potato - and green peas?
Sodium bicarbonate generates CO2
Fatty Acid (Ester linked) to Fatty Alcohol
Gossypol (it is removed during the oil refining process)
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

45. What does the acronym NPN stand for?
Aspartic Acid and Phenylalanine
It explodes
Non-protein nitrogen
45% - 52% - 90%

46. How do sodium chloride and sucrose affect foam stability?
Water
Fructose
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Sodium chloride reduces foam stability and sucrose improves foam stability.

47. What is the Peroxide Value a measure of?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Lipid oxidation
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Fat Oxidation

48. Name one way foam stability can be assessed.
Prolamines
Chlocophyllide does not have a phytoltail
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.
Gossypol (it is removed during the oil refining process)

49. Name two reasons why fats are hydrogenated.
Degradation of protein and production of acid from sugar at the same time.
The speed of a molecule is proportional to the surrounding voltage gradient.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

50. What is the fundamental driving of electrophoresis?
Pheophytin forms
20 carbons and 4 double bonds
The speed of a molecule is proportional to the surrounding voltage gradient.
.05 M HCL