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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. What is Ohm's Law and What is Power Equation?
Water
V=IR and P=VI or I x I x are
Anomeric
Ammonia - Water - Carbon Dioxide

2. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Negative log of the hydrogen concentration (mol/l).
Lamellar; Hexagonal I - II; Cubic
Carrageenan
NaCl (it dissociated to a 2M solution)

3. 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
Covalent (strongest) and Hydrophobic (Weakest)
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Phenophylin

4. What is catalase?
Lipase
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Pectin methyl esterase or galacturonase
An enzyme that converts hydrogen peroxide to water plus oxygen.

5. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Water
Onions ( or leeks)
Fat Oxidation

6. Contains the lowest content of water
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
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Whole Milk
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.

7. What is the chemical nature of anthocyanins?
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
Glycosides of anthocyanidins
Chitin
Sodium chloride reduces foam stability and sucrose improves foam stability.

8. Name the three positively charged amino acids.
Lysine - Arginine - and Histidine
Carmelization and Maillard
Monosodium Glutamate
V=IR and P=VI or I x I x are

9. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Plasmids
Lipid oxidation
Lysine - Arginine - and Histidine
Speed of Light

10. Name three nonpolar polar - and charged amino acids.
Four
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
14

11. What enzyme causes hyrolytic rancidity in milk?
Nucleation or crystal formation and crystal growth.
Speed of Light
Initiation - Propagation - Termination
Lipase

12. Name 3 factors influencing the rate of lipid oxidation in foods.
Phenophylin
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Daminozide
Prolamines

13. Name three effects of protein denaturation.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Tryptophan
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Bitter

14. Name three effects of protein denaturation.
Covalent (strongest) and Hydrophobic (Weakest)
Milk
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)

15. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
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.
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.
Acsulfame-K - Saccharin - Cyclamate - Aspartame

16. What two enzymes degrade pectic substances?
Capsaicin
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.
Pectin methylesterase & polygalacturonase
Degradation of protein and production of acid from sugar at the same time.

17. What is the structural difference between chlorophyll and chlocophyllide?
Chlocophyllide does not have a phytoltail
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Carmelization and Maillard
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

18. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Acetoin
Polyphenol Oxidase
Thermus Aqauticus
Pectin methyl esterase or galacturonase

19. How do sodium chloride and sucrose affect foam stability?
Fatty Acid and Alcohol
Sodium chloride reduces foam stability and sucrose improves foam stability.
Lipid oxidation
Lysine - Arginine - and Histidine

20. What is the Peroxide Value a measure of?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Fat Oxidation
Thamautin
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

21. Name two main gluten proteins.
Racemic Mixture
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Gliadins and Glutenins
Initiation - Propagation - and Termination

22. What toxic pigment is found in cottonseed endosperm?
Browning of freshly cut surfaces of fruits and vegetables.
Gossypol (it is removed during the oil refining process)
No
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.

23. Name two main gluten proteins.
Yes
Covalent (strongest) and Hydrophobic (Weakest)
Gliadins and Glutenins
Parabens

24. When heated ammonium bicarbonate decomposes to form what end 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).
Capsaicin
Ammonia - Water - Carbon Dioxide
Thickener in foods

25. What are the three main steps in the autooxidation of lipids?
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.
Anomeric
It explodes
Initiation - Propagation - Termination

26. What two enzymes degrade pectic substances?
Fat Oxidation
1 - 3 - 7-trimethylxanthine
Pectin methylesterase & polygalacturonase
Monosodium Glutamate

27. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
45% - 52% - 90%
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Capsaicin
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

28. How many carbon atoms are there in the fatty acid myristic acid?
Polyphenoloxidase
Lycopenes
14
Primary butyric acid also caproic acid.

29. Will lipid oxidation be higher at a water activity of .05 or .5?
Arachidonic Acid
.05
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.
2.5

30. What compounds oxidize to form brown color in fruits and vegetables?
Polyphenols
Lipid oxidation
Initiation - Propagation - and Termination
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

31. Waxes are composed of what two basic chemical entities?
Polyphenoloxidase
Yes
Phenylketonuria
Fatty Acid (Ester linked) to Fatty Alcohol

32. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
They act as catalysts - speeding the polymerization of acrylamide.
.05 M HCL
Pheophytia does not have magnesium in porphyrin ring.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

33. What are the four basic flavors perceived by the tongue?
Lycopenes
Sweet - Salty - Sour - and Bitter
Parabens
Carrageenan

34. How does ERH relate to water activity?
ERH=100 x Aw
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
No

35. What is the major color compound in tomatoes?
Pheophytin forms
Lycopenes
2.5
Daminozide

36. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
Gossypol (it is removed during the oil refining process)
Capsaicin
Gliadins and Glutenins

37. What does the acronym NPN stand for?
Blue pigment in flowers
45% - 52% - 90%
Two aldehydes
Non-protein nitrogen

38. What is the enzyme that softens tomatoes?
Pectin Esterase
Onions ( or leeks)
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
.05

39. Name 4 advantages of using enzymes in food processing.
Pheophytia does not have magnesium in porphyrin ring.
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
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Fatty Acid and Alcohol

40. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Water
Negative log of the hydrogen concentration (mol/l).
RNA transcribed to DNA

41. Name the strongest biochemical bond and the weakest biochemical bond.
45% - 52% - 90%
2.5
Covalent (strongest) and Hydrophobic (Weakest)
Four

42. 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
14
.05
Fatty Acid (Ester linked) to Fatty Alcohol
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

43. Name three factors useful in controlling enzyme activity.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
pH below positive charge; pH at no charge; pH above negative charge
Yellow
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

44. What are proteins which are soluble in 50-80% ethanol known as?
Prolamines
It explodes
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Erythorbic Acid

45. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Tryptophan
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
Browning of freshly cut surfaces of fruits and vegetables.
Fat Oxidation

46. Define molarity molality - and normality.
Polyphenol Oxidase
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Chitin
20 carbons and 4 double bonds

47. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
Lipase
Whole Milk
20 carbons and 4 double bonds

48. What is the structural difference between chlorophyll and chlocophyllide?
Chlocophyllide does not have a phytoltail
Olive Green
Sucrose
Ascorbic Acid and Citric Acid

49. What is the Peroxide Value a measure of?
Fat Oxidation
Ascorbic Acid and Citric Acid
Pectin methyl esterase or galacturonase
Lipid oxidation

50. What does the saponification value measure and how is it measured?
Ascorbic Acid and Citric Acid
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Polyphenoloxidase