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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 two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
Degradation of protein and production of acid from sugar at the same time.
Oil in Water
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

2. How many polypeptide chains make up an antibody?
Fatty Acid and Alcohol
Four
It explodes
Thickener in foods

3. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Sucrose
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.
Lipase
Oil in Water

4. Name two reasons why fats are hydrogenated.
Yes
Oil in Water
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Lamellar; Hexagonal I - II; Cubic

5. What are the only phenols approved for use in the microbiological preservation of foods?
Four
Parabens
Nucleation or crystal formation and crystal growth.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

6. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Polyphenols
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Olive Green
pH below positive charge; pH at no charge; pH above negative charge

7. Will lipid oxidation be higher at a water activity of .05 or .5?
V=IR and P=VI or I x I x are
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Nucleation or crystal formation and crystal growth.
.05

8. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Thamautin
V=IR and P=VI or I x I x are
Polyphenol Oxidase
Pectins

9. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
45% - 52% - 90%
Tryptophan
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Two aldehydes

10. What are the only phenols approved for use in the microbiological preservation of foods?
Bitter
Water
Daminozide
Parabens

11. Name 5 chelating agents used in the food industry.
Polyphenol Oxidase
HPLC has higher pressure than FPLC
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Water

12. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
HPLC has higher pressure than FPLC
NaCl (it dissociated to a 2M solution)
Parabens

13. What is the major color compound in tomatoes?
Lycopenes
Lamellar; Hexagonal I - II; Cubic
V=IR and P=VI or I x I x are
Acsulfame-K - Saccharin - Cyclamate - Aspartame

14. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Bitter
Orange Juice
Lysine - Arginine - and Histidine
Gliadins and Glutenins

15. Name two enzymes that are involved in softening fruits.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Yellow
Osmosis
Pectin Esterase - Polygalacturonase - Pectin Layase

16. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
pH 3-5
2.5
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Phenylketonuria

17. What charge will a protein have when the pH of its solution is below at - and above its pKa?
No
Sodium bicarbonate generates CO2
Capsaicin
pH below positive charge; pH at no charge; pH above negative charge

18. Name a commonly used household chemical leavening agent and the gas it generates.
Carmelization and Maillard
Polyphenoloxidase
Sodium bicarbonate generates CO2
Anomeric

19. Name three non-nutritive sweeteners approved for use in USA?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Speed of Light
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Fatty Acid (Ester linked) to Fatty Alcohol

20. What compounds oxidize to form brown color in fruits and vegetables?
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Polyphenols

21. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
It explodes
Bright green
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.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls

22. At what pH is benzoic acid most effective?
Degradation of protein and production of acid from sugar at the same time.
Emulsoids
pH 3-5
.05

23. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Phenylketonuria
Pectin Esterase - Polygalacturonase - Pectin Layase
Nucleation or crystal formation and crystal growth.
Non-protein nitrogen

24. Contains the lowest content of water
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Whole Milk
Lycopenes
ERH=100 x Aw

25. What is catalase?
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
Speed of Light
Pheophytia does not have magnesium in porphyrin ring.
An enzyme that converts hydrogen peroxide to water plus oxygen.

26. 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?
Water
Anomeric
It explodes
pH 3-5

27. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Phenylketonuria
Troponins and Tropomyosin
Polyphenoloxidase
Plasmids

28. Alar is the trade name for what chemical compound?
Chlocophyllide does not have a phytoltail
Emulsoids
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Daminozide

29. What is the main class of color compounds found in raspberries?
Arachidonic Acid
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Sodium bicarbonate generates CO2
Anthocyanins

30. Name a commonly used household chemical leavening agent and the gas it generates.
Troponins and Tropomyosin
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Sodium bicarbonate generates CO2
Racemic Mixture

31. In what food is butyric acid typically found?
14
Degradation of protein and production of acid from sugar at the same time.
Milk
Chlocophyllide does not have a phytoltail

32. What are two common reducing agents that break disulfide bonds in proteins?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Sodium chloride reduces foam stability and sucrose improves foam stability.
Ascorbic Acid and Citric Acid
Linoleic Acid

33. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Plasmids
ERH=100 x Aw
A concentrate of microfibrillar proteins of fish muscle.
Sodium chloride reduces foam stability and sucrose improves foam stability.

34. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Thickener in foods
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
Milk

35. Name three effects of protein denaturation.
Ascorbic Acid and Citric Acid
.05
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Lipid oxidation

36. What does the iodine 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.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin methyl esterase or galacturonase
Glycosides of anthocyanidins

37. What is the name given to a mixture of equal parts of Darel Lisomers?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Lipase
Gossypol (it is removed during the oil refining process)
Racemic Mixture

38. Name 3 factors influencing the rate of lipid oxidation in foods.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Phenophylin
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

39. What is the Peroxide Value a measure of?
Fat Oxidation
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Daminozide
pH below positive charge; pH at no charge; pH above negative charge

40. What pigment was first designated as anthocyanins?
Blue pigment in flowers
Water
Four
Aspartic Acid and Phenylalanine

41. What are the primary secondary - tertiary - and quaternary structures?
Erythorbic Acid
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Initiation - Propagation - and Termination
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.

42. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Yellow
Olive Green
Bitter
.05

43. How is pH defined?
pH below positive charge; pH at no charge; pH above negative charge
Ascorbic Acid and Citric Acid
Milk
Negative log of the hydrogen concentration (mol/l).

44. Define molarity molality - and normality.
Pheophytia does not have magnesium in porphyrin ring.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
They act as catalysts - speeding the polymerization of acrylamide.
Fatty Acid and Alcohol

45. Is a disaccharide
Blue pigment in flowers
Polyphenol Oxidase
Sucrose
Acetoin

46. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
Troponins and Tropomyosin
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Ascorbic Acid and Citric Acid

47. What metabolic end product does the Voges-Proskauer test detect?
Acetoin
The speed of a molecule is proportional to the surrounding voltage gradient.
A concentrate of microfibrillar proteins of fish muscle.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

48. Name two non-enzymatic browning reactions.
Oil in Water
Carmelization and Maillard
Capsaicin
Glycosides of anthocyanidins

49. 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
Initiation - Propagation - Termination
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Lysine - Arginine - and Histidine

50. What does the 'c' stand for in the equation E=mc2?
Speed of Light
Racemic Mixture
Negative log of the hydrogen concentration (mol/l).
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.