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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 the Peroxide Value a measure of?
Oil in Water
Fat Oxidation
Thickener in foods
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

2. What metabolic end product does the Voges-Proskauer test detect?
Acetoin
Sucrose
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.
Polyphenols

3. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Bitter
Daminozide
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
Milk

4. What is catalase?
Lycopenes
Speed of Light
Acsulfame-K - Saccharin - Cyclamate - Aspartame
An enzyme that converts hydrogen peroxide to water plus oxygen.

5. What does the iodine value measure and how is it measured?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
1 - 3 - 7-trimethylxanthine
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Sodium chloride reduces foam stability and sucrose improves foam stability.

6. Give one word for a carbon atom involved in hemiacetal or acetal formation.
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.
Pectin Esterase
Anomeric

7. What pigment was first designated as anthocyanins?
14
Acetoin
Blue pigment in flowers
Pectin methyl esterase or galacturonase

8. 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.
Covalent (strongest) and Hydrophobic (Weakest)
Bright green
45% - 52% - 90%

9. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Blue pigment in flowers
Erythorbic Acid
Pectin methyl esterase or galacturonase
Pectins

10. What is the fundamental driving of electrophoresis?
Water
The speed of a molecule is proportional to the surrounding voltage gradient.
Four
Ascorbic Acid and Citric Acid

11. What toxic pigment is found in cottonseed endosperm?
Osmosis
D: None of the above
Gossypol (it is removed during the oil refining process)
No

12. What are the primary secondary - tertiary - and quaternary structures?
HPLC has higher pressure than FPLC
Milk
Acetoin
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.

13. What happens to a bottle of wine if before you bottle it you forget to put the stuff in it that prevents it from fermenting?
Yellow
It explodes
V=IR and P=VI or I x I x are
Prolamines

14. Will lipid oxidation be higher at a water activity of .05 or .5?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
.05
They act as catalysts - speeding the polymerization of acrylamide.
Gliadins and Glutenins

15. How does HPLC differ from FPLC?
Troponins and Tropomyosin
Thermus Aqauticus
HPLC has higher pressure than FPLC
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

16. 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.
45% - 52% - 90%
Water
Yes

17. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
Carmelization and Maillard
Two aldehydes
Fatty Acid and Alcohol
Thermus Aqauticus

18. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Speed of Light
Olive Green
Covalent (strongest) and Hydrophobic (Weakest)
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

19. How many polypeptide chains make up an antibody?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
.05
Ascorbic Acid and Citric Acid
Four

20. Waxes are composed of what two basic chemical entities?
Fatty Acid (Ester linked) to Fatty Alcohol
Orange Juice
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Prolamines

21. What ketohexose is most significant to food chemists?
Onions ( or leeks)
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Negative log of the hydrogen concentration (mol/l).
Fructose

22. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
It explodes
Carrageenan
Pectin methyl esterase or galacturonase

23. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Monosodium Glutamate
Acsulfame-K - Saccharin - Cyclamate - Aspartame
No
pH below positive charge; pH at no charge; pH above negative charge

24. What ketohexose is most significant to food chemists?
Fructose
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams 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
DNA transferred by cell to cell contact (bacterial sex).

25. What is the structural difference between chlorophyll and chlocophyllide?
20 carbons and 4 double bonds
Chlocophyllide does not have a phytoltail
Degradation of protein and production of acid from sugar at the same time.
Acsulfame-K - Saccharin - Cyclamate - Aspartame

26. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
.05 M HCL
Glycosides of anthocyanidins
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

27. What is the structural difference between chlorophyll and pheophytia?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Pheophytia does not have magnesium in porphyrin ring.
Aspartic Acid and Phenylalanine

28. Name two main gluten proteins.
Lipase
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
Whole Milk
Gliadins and Glutenins

29. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Pheophytin forms
V=IR and P=VI or I x I x are
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Sodium bicarbonate generates CO2

30. What is the structural difference between chlorophyll and chlocophyllide?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Chlocophyllide does not have a phytoltail
Acetoin
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

31. 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?
Ascorbic Acid and Citric Acid
.05 M HCL
An enzyme that converts hydrogen peroxide to water plus oxygen.
Blue pigment in flowers

32. What is acid proteolysis?
Erythorbic Acid
Fat Oxidation
Degradation of protein and production of acid from sugar at the same time.
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

33. Name the strongest biochemical bond and the weakest biochemical bond.
1 - 3 - 7-trimethylxanthine
Negative log of the hydrogen concentration (mol/l).
Anthocyanins
Covalent (strongest) and Hydrophobic (Weakest)

34. What two enzymes degrade pectic substances?
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
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Prolamines

35. Peptide bond formation results in the formation of what secondary compound?
Gossypol (it is removed during the oil refining process)
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Water

36. What is the Peroxide Value a measure of?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Fat Oxidation
Olive Green
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

37. What is the enzyme responsible for browning in apples and lettuce?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Aspartic Acid and Phenylalanine
Polyphenol Oxidase
Pectin Esterase - Polygalacturonase - Pectin Layase

38. How can a molecular weight of protein - DNA - and RNA be determined?
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
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

39. Name a commonly used household chemical leavening agent and the gas it generates.
Sodium bicarbonate generates CO2
HPLC has higher pressure than FPLC
An enzyme that converts hydrogen peroxide to water plus oxygen.
They act as catalysts - speeding the polymerization of acrylamide.

40. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
2.5
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Bitter
Fatty Acid (Ester linked) to Fatty Alcohol

41. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
.05 M HCL
Covalent (strongest) and Hydrophobic (Weakest)
Acetoin
Tryptophan

42. What effect would the addition of sodium bicarbonate have to chocolate?
They act as catalysts - speeding the polymerization of acrylamide.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Phenylketonuria

43. Name the two components that comprise the relaxing factor in muscle fibers.
Four
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Troponins and Tropomyosin

44. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
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.
Aspartic Acid and Phenylalanine
Daminozide

45. 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
Prolamines
Onions ( or leeks)
Polyphenol Oxidase

46. Which two amino acids is the aspartame derived from?
Aspartic Acid and Phenylalanine
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
Olive Green
NaCl (it dissociated to a 2M solution)

47. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
They act as catalysts - speeding the polymerization of acrylamide.
NaCl (it dissociated to a 2M solution)
Chlocophyllide does not have a phytoltail

48. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
V=IR and P=VI or I x I x are
Browning of freshly cut surfaces of fruits and vegetables.
Lipid oxidation
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

49. Name two non-enzymatic browning reactions.
Non-protein nitrogen
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Carmelization and Maillard
Thamautin

50. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
RNA transcribed to DNA
.05 M HCL
20 carbons and 4 double bonds
Sucrose