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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. At what pH is benzoic acid most effective?
Fatty Acid and Alcohol
Initiation - Propagation - and Termination
Osmosis
pH 3-5

2. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bitter
Bright green
Troponins and Tropomyosin
The speed of a molecule is proportional to the surrounding voltage gradient.

3. What is surimi?
Water
A concentrate of microfibrillar proteins of fish muscle.
Polyphenol Oxidase
Yellow

4. Name 4 advantages of using enzymes in food processing.
Phenylketonuria
Lipase
Bright green
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

5. What are the four basic flavors perceived by the tongue?
Sweet - Salty - Sour - and Bitter
Water
14
Pectin methylesterase & polygalacturonase

6. Peptide bond formation results in the formation of what secondary compound?
DNA transferred by cell to cell contact (bacterial sex).
Thamautin
Water
Anthocyanins

7. What is the Peroxide Value a measure of?
pH 3-5
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Fat Oxidation
Racemic Mixture

8. What is the chemical nomenclature for caffeine?
1 - 3 - 7-trimethylxanthine
Glycosides of anthocyanidins
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.
Chitin

9. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Cis
A concentrate of microfibrillar proteins of fish muscle.
Speed of Light

10. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Thickener in foods
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Phenylketonuria

11. What is catalase?
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Cis
An enzyme that converts hydrogen peroxide to water plus oxygen.

12. Name 3 factors influencing the rate of lipid oxidation in foods.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Phenophylin
pH below positive charge; pH at no charge; pH above negative charge
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

13. How do sodium chloride and sucrose affect foam stability?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Osmosis
Acsulfame-K - Saccharin - Cyclamate - Aspartame
They act as catalysts - speeding the polymerization of acrylamide.

14. Name 3 factors influencing the rate of lipid oxidation in foods.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Aspartic Acid and Phenylalanine
Polyphenols
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.

15. Waxes are composed of what two basic chemical entities?
RNA transcribed to DNA
Yes
Fatty Acid (Ester linked) to Fatty Alcohol
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.

16. What enzyme causes hyrolytic rancidity in milk?
Lycopenes
Capsaicin
Lipase
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls

17. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Osmosis
Polyphenoloxidase
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

18. What is the main class of color compounds found in raspberries?
Pectins
Anthocyanins
HPLC has higher pressure than FPLC
Daminozide

19. Name two non-enzymatic browning reactions.
Troponins and Tropomyosin
Carmelization and Maillard
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.
20 carbons and 4 double bonds

20. What two types of compounds are joined with an ester bond to make a wax?
Pectin Esterase - Polygalacturonase - Pectin Layase
Troponins and Tropomyosin
45% - 52% - 90%
Fatty Acid and Alcohol

21. Does kosmotrophil ion discourage water structure?
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
No
Racemic Mixture
pH below positive charge; pH at no charge; pH above negative charge

22. Peptide bond formation results in the formation of what secondary compound?
Pheophytia does not have magnesium in porphyrin ring.
Polyphenol Oxidase
1 - 3 - 7-trimethylxanthine
Water

23. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Bright green
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.
Pectin methyl esterase or galacturonase
Polyphenoloxidase

24. What is the major color compound in tomatoes?
Gossypol (it is removed during the oil refining process)
Lycopenes
Anomeric
Daminozide

25. 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
Non-protein nitrogen
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.
D: None of the above
Arachidonic Acid

26. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Anomeric
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.
Pectins
Lipase

27. What is the structural difference between chlorophyll and pheophytia?
Pheophytia does not have magnesium in porphyrin ring.
Covalent (strongest) and Hydrophobic (Weakest)
Acetoin
Bright green

28. How is pH defined?
Negative log of the hydrogen concentration (mol/l).
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Water
The speed of a molecule is proportional to the surrounding voltage gradient.

29. What metabolic end product does the Voges-Proskauer test detect?
Acetoin
Sucrose
2.5
Onions ( or leeks)

30. Is a disaccharide
Sucrose
Racemic Mixture
pH below positive charge; pH at no charge; pH above negative charge
Chlocophyllide does not have a phytoltail

31. What is the enzyme that softens tomatoes?
Pectin Esterase
Oil in Water
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

32. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Yes
Anomeric
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Four

33. Name three effects of protein denaturation.
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Troponins and Tropomyosin
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Sodium chloride reduces foam stability and sucrose improves foam stability.

34. Name 3 chemical agents capable of denaturing proteins.
Olive Green
Four
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Primary butyric acid also caproic acid.

35. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
NaCl (it dissociated to a 2M solution)
Water
Thermus Aqauticus

36. What is the fundamental driving of electrophoresis?
Lipid oxidation
The speed of a molecule is proportional to the surrounding voltage gradient.
Two aldehydes
45% - 52% - 90%

37. Name three nonpolar polar - and charged amino acids.
DNA transferred by cell to cell contact (bacterial sex).
Browning of freshly cut surfaces of fruits and vegetables.
Lysine - Arginine - and Histidine
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

38. What are the primary secondary - tertiary - and quaternary structures?
Phenophylin
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.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Thermus Aqauticus

39. Alar is the trade name for what chemical compound?
Thamautin
Daminozide
Prolamines
Aspartic Acid and Phenylalanine

40. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Gliadins and Glutenins
Tryptophan
Browning of freshly cut surfaces of fruits and vegetables.

41. What is the chemical nature of anthocyanins?
Orange Juice
Water
Glycosides of anthocyanidins
Lysine - Arginine - and Histidine

42. What are 3 mesomorphic structures associated with lipids in the liquid state?
Thamautin
Blue pigment in flowers
Lamellar; Hexagonal I - II; Cubic
Primary butyric acid also caproic acid.

43. What enzyme causes hyrolytic rancidity in milk?
Browning of freshly cut surfaces of fruits and vegetables.
Lipase
Four
Covalent (strongest) and Hydrophobic (Weakest)

44. What is the structural difference between chlorophyll and chlocophyllide?
Parabens
Chlocophyllide does not have a phytoltail
Whole Milk
Orange Juice

45. Name three non-nutritive sweeteners approved for use in USA?
Anomeric
Osmosis
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
Acsulfame-K - Saccharin - Cyclamate - Aspartame

46. Name two main gluten proteins.
Gliadins and Glutenins
Sweet - Salty - Sour - and Bitter
Osmosis
Capsaicin

47. What does HLB stand for and What does a high and low HLB value indicate?
Pectin Esterase
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.
Browning of freshly cut surfaces of fruits and vegetables.
Carrageenan

48. What pigment was first designated as anthocyanins?
They act as catalysts - speeding the polymerization of acrylamide.
Chitin
Blue pigment in flowers
Speed of Light

49. What is acid proteolysis?
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
Degradation of protein and production of acid from sugar at the same time.
Two aldehydes
The speed of a molecule is proportional to the surrounding voltage gradient.

50. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
HPLC has higher pressure than FPLC
Thermus Aqauticus
Daminozide
Osmosis