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Food Chemistry

Instructions:

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. Are sorbitol and mannitol sweet?
They act as catalysts - speeding the polymerization of acrylamide.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Yes

2. 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?
Phenylketonuria
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
.05 M HCL
Thickener in foods

3. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Yellow
Linoleic Acid
Browning of freshly cut surfaces of fruits and vegetables.
Pectin methyl esterase or galacturonase

4. What enzyme causes hyrolytic rancidity in milk?
Polyphenol Oxidase
Lipase
V=IR and P=VI or I x I x are
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

5. 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
Four
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
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

6. Name the strongest biochemical bond and the weakest biochemical bond.
RNA transcribed to DNA
Thickener in foods
Blue pigment in flowers
Covalent (strongest) and Hydrophobic (Weakest)

7. What is catalase?
pH 3-5
An enzyme that converts hydrogen peroxide to water plus oxygen.
20 carbons and 4 double bonds
Ascorbic Acid and Citric Acid

8. Name two non-enzymatic browning reactions.
Carmelization and Maillard
Fat Oxidation
Pectin methylesterase & polygalacturonase
Polyphenol Oxidase

9. What is Carboxy-methyl cellulose often used for?
The speed of a molecule is proportional to the surrounding voltage gradient.
Sodium chloride reduces foam stability and sucrose improves foam stability.
An enzyme that converts hydrogen peroxide to water plus oxygen.
Thickener in foods

10. What is the enzyme that softens tomatoes?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Fat Oxidation
Pectin Esterase
D: None of the above

11. How can a molecular weight of protein - DNA - and RNA be determined?
NaCl (it dissociated to a 2M solution)
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

12. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
Pectin methyl esterase or galacturonase
Yellow
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls

13. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Water
Milk
Pectin methyl esterase or galacturonase
Phenophylin

14. Name two non-enzymatic browning reactions.
Erythorbic Acid
Carmelization and Maillard
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.
Polyphenol Oxidase

15. 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
pH below positive charge; pH at no charge; pH above negative charge
Gossypol (it is removed during the oil refining process)
Emulsoids
Browning of freshly cut surfaces of fruits and vegetables.

16. What are 3 mesomorphic structures associated with lipids in the liquid state?
Cis
Bright green
Lamellar; Hexagonal I - II; Cubic
Ascorbic Acid and Citric Acid

17. When heated ammonium bicarbonate decomposes to form what end products?
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
pH below positive charge; pH at no charge; pH above negative charge
Ammonia - Water - Carbon Dioxide
Carrageenan

18. What is the major color compound in tomatoes?
Ascorbic Acid and Citric Acid
Ammonia - Water - Carbon Dioxide
Lycopenes
Carmelization and Maillard

19. During freezing What are the two stages in the crystallization process?
45% - 52% - 90%
Nucleation or crystal formation and crystal growth.
Water
Fat Oxidation

20. What two enzymes degrade pectic substances?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Pectin methylesterase & polygalacturonase
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Monosodium Glutamate

21. How many polypeptide chains make up an antibody?
Daminozide
Osmosis
DNA transferred by cell to cell contact (bacterial sex).
Four

22. What is the main class of color compounds found in raspberries?
Bitter
Anthocyanins
Pectin methyl esterase or galacturonase
Erythorbic Acid

23. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
D: None of the above
Milk

24. Name two enzymes that are involved in softening fruits.
Osmosis
NaCl (it dissociated to a 2M solution)
Acetoin
Pectin Esterase - Polygalacturonase - Pectin Layase

25. What is the geometric configuration of double bonds in most natural fatty acids?
.05 M HCL
.05
Cis
Negative log of the hydrogen concentration (mol/l).

26. Name a commonly used household chemical leavening agent and the gas it generates.
Polyphenol Oxidase
Sodium bicarbonate generates CO2
No
Lipase

27. Name 3 factors influencing the rate of lipid oxidation in foods.
Nucleation or crystal formation and crystal growth.
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Troponins and Tropomyosin
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

28. In genetics What is conjugation?
Fatty Acid and Alcohol
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Water
DNA transferred by cell to cell contact (bacterial sex).

29. Name two main gluten proteins.
Prolamines
Gliadins and Glutenins
Chlocophyllide does not have a phytoltail
Emulsoids

30. What is the name given to a mixture of equal parts of Darel Lisomers?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
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.
Racemic Mixture
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

31. What pigment was first designated as anthocyanins?
Olive Green
Acetoin
Blue pigment in flowers
Oil in Water

32. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Osmosis
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.
Degradation of protein and production of acid from sugar at the same time.
Polyphenol Oxidase

33. What is the structural difference between chlorophyll and chlocophyllide?
RNA transcribed to DNA
Gossypol (it is removed during the oil refining process)
45% - 52% - 90%
Chlocophyllide does not have a phytoltail

34. Does kosmotrophil ion discourage water structure?
Emulsification
Whole Milk
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
No

35. What enzyme is most responsible for browning bananas?
Sweet - Salty - Sour - and Bitter
Polyphenol Oxidase
An enzyme that converts hydrogen peroxide to water plus oxygen.
Pectin Esterase - Polygalacturonase - Pectin Layase

36. Waxes are composed of what two basic chemical entities?
Milk
pH 3-5
Fatty Acid (Ester linked) to Fatty Alcohol
Sodium chloride reduces foam stability and sucrose improves foam stability.

37. What does the 'c' stand for in the equation E=mc2?
Speed of Light
Two aldehydes
Milk
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

38. 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.
Covalent (strongest) and Hydrophobic (Weakest)
14
Chitin

39. At low water activity What is the main deteriorative concern?
Chlocophyllide does not have a phytoltail
Prolamines
Erythorbic Acid
Lipid oxidation

40. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Lipid oxidation
NaCl (it dissociated to a 2M solution)
Non-protein nitrogen

41. Name the three positively charged amino acids.
Lysine - Arginine - and Histidine
Anomeric
Bright green
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

42. At what pH is benzoic acid most effective?
Daminozide
pH 3-5
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
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.

43. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Tryptophan
Prolamines
Oil in Water
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.

44. Name 5 proteins with good foaming properties.
Thickener in foods
Browning of freshly cut surfaces of fruits and vegetables.
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

45. Will lipid oxidation be higher at a water activity of .05 or .5?
Pheophytia does not have magnesium in porphyrin ring.
Chitin
.05
Carmelization and Maillard

46. What are the four basic flavors perceived by the tongue?
Bright green
Four
Sweet - Salty - Sour - and Bitter
A concentrate of microfibrillar proteins of fish muscle.

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

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48. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
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.
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.
Acetoin

49. What are the only phenols approved for use in the microbiological preservation of foods?
Pectin methyl esterase or galacturonase
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.
Parabens
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

50. What two types of compounds are joined with an ester bond to make a wax?
Fatty Acid and Alcohol
Onions ( or leeks)
Plasmids
Butter= water in oil Mayonnaise= oil in water Milk= oil in water