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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. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
They act as catalysts - speeding the polymerization of acrylamide.
.05
Polyphenol Oxidase
Bright green

2. What does HLB stand for and What does a high and low HLB value indicate?
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.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
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
Initiation - Propagation - and Termination

3. What is the chemical nature of anthocyanins?
2.5
Sweet - Salty - Sour - and Bitter
Sweet - Salty - Sour - and Bitter
Glycosides of anthocyanidins

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

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

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6. During freezing What are the two stages in the crystallization process?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Cis
Nucleation or crystal formation and crystal growth.
Pectin Esterase - Polygalacturonase - Pectin Layase

7. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Polyphenol Oxidase
NaCl (it dissociated to a 2M solution)
Carrageenan
ERH=100 x Aw

8. What is the Peroxide Value a measure of?
pH 3-5
Thermus Aqauticus
Fat Oxidation
Lysine - Arginine - and Histidine

9. What are the limiting amino acids in corn - potato - and green peas?
Speed of Light
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Sodium chloride reduces foam stability and sucrose improves foam stability.
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

10. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Acetoin
Olive Green
Nucleation or crystal formation and crystal growth.
Gliadins and Glutenins

11. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
pH 3-5
Bitter
Fatty Acid and Alcohol
Polyphenoloxidase

12. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Whole Milk
The speed of a molecule is proportional to the surrounding voltage gradient.

13. What is the chemical nature of anthocyanins?
Fructose
Glycosides of anthocyanidins
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

14. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Daminozide
Phenylketonuria
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
45% - 52% - 90%

15. What are soluble polymers of anhydro-galacturonic acid and its esters called?
45% - 52% - 90%
Pheophytin forms
Pectins
Thermus Aqauticus

16. How does ERH relate to water activity?
RNA transcribed to DNA
Gossypol (it is removed during the oil refining process)
ERH=100 x Aw
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

17. Name the strongest biochemical bond and the weakest biochemical bond.
Fat Oxidation
Monosodium Glutamate
Covalent (strongest) and Hydrophobic (Weakest)
Pectin methyl esterase or galacturonase

18. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Polyphenoloxidase
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Ascorbic Acid and Citric Acid
Racemic Mixture

19. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Monosodium Glutamate
Onions ( or leeks)
NaCl (it dissociated to a 2M solution)
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

20. Match the number of carbon atoms with the common name of these saturated fatty acids. Carbon #: 4:0 10:0 - 12:0 -14:0 - 16:0 - 18:0Common Name: Myristic - Butyric - Capric - Lauric - Stearic - Palmitic
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Ascorbic Acid and Citric Acid
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
pH below positive charge; pH at no charge; pH above negative charge

21. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Anomeric
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.
14
Polyphenoloxidase

22. Name the strongest biochemical bond and the weakest biochemical bond.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Arachidonic Acid
Covalent (strongest) and Hydrophobic (Weakest)
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

23. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
pH 3-5
Sodium bicarbonate generates CO2
45% - 52% - 90%
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

24. How many polypeptide chains make up an antibody?
Four
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
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
Bitter

25. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Ammonia - Water - Carbon Dioxide
Thermus Aqauticus
They act as catalysts - speeding the polymerization of acrylamide.

26. Waxes are composed of what two basic chemical entities?
Erythorbic Acid
Fatty Acid (Ester linked) to Fatty Alcohol
Four
Degradation of protein and production of acid from sugar at the same time.

27. What enzyme is most responsible for browning bananas?
Oil in Water
Thermus Aqauticus
Polyphenol Oxidase
Sweet - Salty - Sour - and Bitter

28. Name the two components that comprise the relaxing factor in muscle fibers.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Troponins and Tropomyosin
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Pectins

29. What are the primary secondary - tertiary - and quaternary structures?
pH below positive charge; pH at no charge; pH above negative charge
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.
14
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

30. What does the iodine value measure and how is it measured?
Fructose
Carrageenan
Emulsification
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

31. What two common compounds are used together as an antioxidative system?
Lysine - Arginine - and Histidine
ERH=100 x Aw
Sodium chloride reduces foam stability and sucrose improves foam stability.
Ascorbic Acid and Citric Acid

32. What does MSG stand for?
Ammonia - Water - Carbon Dioxide
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Monosodium Glutamate
Four

33. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Milk
pH below positive charge; pH at no charge; pH above negative charge
Yellow
Racemic Mixture

34. Name two non-enzymatic browning reactions.
Carmelization and Maillard
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Pheophytin forms

35. Name two enzymes that are involved in softening fruits.
V=IR and P=VI or I x I x are
Pectin Esterase - Polygalacturonase - Pectin Layase
Sodium chloride reduces foam stability and sucrose improves foam stability.
Osmosis

36. What are the three stages of oxidative rancidity?
Whole Milk
Water
Initiation - Propagation - and Termination
Prolamines

37. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
NaCl (it dissociated to a 2M solution)
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Acsulfame-K - Saccharin - Cyclamate - Aspartame

38. What does the 'c' stand for in the equation E=mc2?
Speed of Light
Browning of freshly cut surfaces of fruits and vegetables.
Phenophylin
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

39. How is pH defined?
Orange Juice
Orange Juice
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Negative log of the hydrogen concentration (mol/l).

40. What is an isomer that is cheaper than Vitamin C?
Chitin
Erythorbic Acid
Ascorbic Acid and Citric Acid
Orange Juice

41. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Parabens
They act as catalysts - speeding the polymerization of acrylamide.
Carrageenan
Plasmids

42. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
D: None of the above
An enzyme that converts hydrogen peroxide to water plus oxygen.
Orange Juice

43. Name a commonly used household chemical leavening agent and the gas it generates.
Gossypol (it is removed during the oil refining process)
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
14
Sodium bicarbonate generates CO2

44. What two enzymes degrade pectic substances?
Thamautin
Pectin methylesterase & polygalacturonase
Speed of Light
Chitin

45. 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.
Yes
Sweet - Salty - Sour - and Bitter
Pectin Esterase - Polygalacturonase - Pectin Layase

46. What is the name of the degradation compound of chlorophyll?
Glycosides of anthocyanidins
ERH=100 x Aw
Phenophylin
Troponins and Tropomyosin

47. Name 3 physical agents capable of denaturing proteins.
Lipase
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Lycopenes
Onions ( or leeks)

48. What is catalase?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
An enzyme that converts hydrogen peroxide to water plus oxygen.
Prolamines
Aspartic Acid and Phenylalanine

49. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Yellow
Phenylketonuria
Two aldehydes
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

50. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
20 carbons and 4 double bonds
Whole Milk
Non-protein nitrogen
They act as catalysts - speeding the polymerization of acrylamide.