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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. Name the strongest biochemical bond and the weakest biochemical bond.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Covalent (strongest) and Hydrophobic (Weakest)
Non-protein nitrogen
A concentrate of microfibrillar proteins of fish muscle.

2. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
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.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Phenophylin

3. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Thickener in foods
The speed of a molecule is proportional to the surrounding voltage gradient.
Anomeric

4. What is the structural difference between chlorophyll and pheophytia?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
1 - 3 - 7-trimethylxanthine
HPLC has higher pressure than FPLC
Pheophytia does not have magnesium in porphyrin ring.

5. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
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.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Pectin methyl esterase or galacturonase

6. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Plasmids
Daminozide
Pectin Esterase
Polyphenols

7. Name three factors useful in controlling enzyme activity.
D: None of the above
Yes
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Ammonia - Water - Carbon Dioxide

8. Name three non-nutritive sweeteners approved for use in USA?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Lamellar; Hexagonal I - II; Cubic
Water
Pheophytin forms

9. What are the three stages of oxidative rancidity?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Initiation - Propagation - and Termination
Pectin Esterase - Polygalacturonase - Pectin Layase
Sucrose

10. What would be a safe processing time for heat processing green beans in a boiling water bath? A. 30 minutes B. 300 minutes C. Depends on the size of the food container D. None of the above
.05
Racemic Mixture
Emulsoids
D: None of the above

11. What are the four basic flavors perceived by the tongue?
Erythorbic Acid
DNA transferred by cell to cell contact (bacterial sex).
Sweet - Salty - Sour - and Bitter
HPLC has higher pressure than FPLC

12. Will lipid oxidation be higher at a water activity of .05 or .5?
Pheophytin forms
.05
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

13. What is the name given to a mixture of equal parts of Darel Lisomers?
2.5
Ascorbic Acid and Citric Acid
Degradation of protein and production of acid from sugar at the same time.
Racemic Mixture

14. In genetics What is conjugation?
DNA transferred by cell to cell contact (bacterial sex).
Polyphenoloxidase
Onions ( or leeks)
pH 3-5

15. What are colloids that are stabilized by a layer of solvation called?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
.05
Emulsoids
20 carbons and 4 double bonds

16. How is pH defined?
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.
Lipid oxidation
Negative log of the hydrogen concentration (mol/l).

17. Name 3 physical agents capable of denaturing proteins.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Thermus Aqauticus
Monosodium Glutamate
Erythorbic Acid

18. What charge will a protein have when the pH of its solution is below at - and above its pKa?
pH below positive charge; pH at no charge; pH above negative charge
They act as catalysts - speeding the polymerization of acrylamide.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Carmelization and Maillard

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

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20. What two common compounds are used together as an antioxidative system?
Olive Green
Yes
Thamautin
Ascorbic Acid and Citric Acid

21. What is the chemical nature of anthocyanins?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Glycosides of anthocyanidins
Daminozide
Prolamines

22. 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.
V=IR and P=VI or I x I x are
Acsulfame-K - Saccharin - Cyclamate - Aspartame
HPLC has higher pressure than FPLC

23. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Thamautin
Chlocophyllide does not have a phytoltail
RNA transcribed to DNA
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

24. What is the major color compound in tomatoes?
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
No
Lycopenes
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

25. At what pH is benzoic acid most effective?
Oil in Water
pH 3-5
Fatty Acid and Alcohol
Polyphenols

26. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Pectin Esterase - Polygalacturonase - Pectin Layase
Cis
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Anthocyanins

27. Name 4 advantages of using enzymes in food processing.
Orange Juice
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
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
RNA transcribed to DNA

28. How many carbon atoms and how many double bonds are there in arachidonic acid?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Fructose
An enzyme that converts hydrogen peroxide to water plus oxygen.
20 carbons and 4 double bonds

29. What is Carboxy-methyl cellulose often used for?
Thickener in foods
Monosodium Glutamate
Pectin Esterase
Water

30. Name a commonly used household chemical leavening agent and the gas it generates.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Pheophytia does not have magnesium in porphyrin ring.
Ascorbic Acid and Citric Acid
Sodium bicarbonate generates CO2

31. What happens to chlorophyll on heating?
Lipid oxidation
Glycosides of anthocyanidins
Pectin methylesterase & polygalacturonase
Pheophytin forms

32. Is a disaccharide
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
HPLC has higher pressure than FPLC
Sucrose
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

33. What does the acronym NPN stand for?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Fatty Acid (Ester linked) to Fatty Alcohol
Non-protein nitrogen
Fructose

34. Waxes are composed of what two basic chemical entities?
Emulsoids
HPLC has higher pressure than FPLC
Fatty Acid (Ester linked) to Fatty Alcohol
Monosodium Glutamate

35. Waxes are composed of what two basic chemical entities?
Aspartic Acid and Phenylalanine
Fatty Acid (Ester linked) to Fatty Alcohol
Troponins and Tropomyosin
Acetoin

36. Peptide bond formation results in the formation of what secondary compound?
RNA transcribed to DNA
Sodium chloride reduces foam stability and sucrose improves foam stability.
Carmelization and Maillard
Water

37. How many polypeptide chains make up an antibody?
Lipase
Four
They act as catalysts - speeding the polymerization of acrylamide.
Phenophylin

38. Which two amino acids is the aspartame derived from?
Pectin methyl esterase or galacturonase
Covalent (strongest) and Hydrophobic (Weakest)
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Aspartic Acid and Phenylalanine

39. During freezing What are the two stages in the crystallization process?
Pectin methyl esterase or galacturonase
Thermus Aqauticus
Polyphenoloxidase
Nucleation or crystal formation and crystal growth.

40. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Daminozide
Lycopenes
.05 M HCL
RNA transcribed to DNA

41. How do sodium chloride and sucrose affect foam stability?
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.
Chlocophyllide does not have a phytoltail
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

42. Name the most common functional property of phospholipids in food systems.
Phenophylin
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Emulsification
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

43. Name two reasons why fats are hydrogenated.
Pectin Esterase - Polygalacturonase - Pectin Layase
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Carrageenan

44. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Polyphenoloxidase
Glycosides of anthocyanidins
Emulsification
Olive Green

45. How many polypeptide chains make up an antibody?
Arachidonic Acid
Chitin
20 carbons and 4 double bonds
Four

46. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Chitin
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

47. What does MSG stand for?
Emulsification
Monosodium Glutamate
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Lysine - Arginine - and Histidine

48. Define molarity molality - and normality.
Prolamines
Pectin methyl esterase or galacturonase
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Parabens

49. At low water activity What is the main deteriorative concern?
Racemic Mixture
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Glycosides of anthocyanidins
Lipid oxidation

50. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
RNA transcribed to DNA
pH 3-5
Degradation of protein and production of acid from sugar at the same time.
Osmosis