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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. What toxic pigment is found in cottonseed endosperm?
Gossypol (it is removed during the oil refining process)
Non-protein nitrogen
Thamautin
Carrageenan

2. What is the name of the degradation compound of chlorophyll?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Negative log of the hydrogen concentration (mol/l).
Phenophylin

3. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Covalent (strongest) and Hydrophobic (Weakest)
Chitin
Initiation - Propagation - Termination
Ammonia - Water - Carbon Dioxide

4. Does kosmotrophil ion discourage water structure?
Browning of freshly cut surfaces of fruits and vegetables.
Polyphenoloxidase
Acsulfame-K - Saccharin - Cyclamate - Aspartame
No

5. What effect would the addition of sodium bicarbonate have to chocolate?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Phenylketonuria
Pectins
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

6. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Two aldehydes
Pheophytin forms
Carmelization and Maillard

7. What enzyme is most responsible for browning bananas?
Sodium bicarbonate generates CO2
Polyphenol Oxidase
Glycosides of anthocyanidins
Phenylketonuria

8. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
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.
Lycopenes
RNA transcribed to DNA
Thermus Aqauticus

9. What enzyme causes hyrolytic rancidity in milk?
Pheophytin forms
Lipase
Bright green
Parabens

10. Name two reasons why fats are hydrogenated.
Phenylketonuria
Initiation - Propagation - Termination
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Anomeric

11. Name 5 proteins with good foaming properties.
Carmelization and Maillard
Sodium chloride reduces foam stability and sucrose improves foam stability.
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.
Carmelization and Maillard

12. How do sodium chloride and sucrose affect foam stability?
Pheophytin forms
Sodium chloride reduces foam stability and sucrose improves foam stability.
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 (Ester linked) to Fatty Alcohol

13. What are colloids that are stabilized by a layer of solvation called?
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.
Water
Emulsoids
Arachidonic Acid

14. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Phenylketonuria
Sucrose
HPLC has higher pressure than FPLC
Carrageenan

15. What is the Peroxide Value a measure of?
Fat Oxidation
Primary butyric acid also caproic acid.
Parabens
Ammonia - Water - Carbon Dioxide

16. What are the three main steps in the autooxidation of lipids?
pH below positive charge; pH at no charge; pH above negative charge
Speed of Light
Initiation - Propagation - Termination
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

17. What is Ohm's Law and What is Power Equation?
V=IR and P=VI or I x I x are
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
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.

18. At low water activity What is the main deteriorative concern?
Ascorbic Acid and Citric Acid
Lipid oxidation
Whole Milk
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

19. What are the only phenols approved for use in the microbiological preservation of foods?
Degradation of protein and production of acid from sugar at the same time.
Parabens
Lamellar; Hexagonal I - II; Cubic
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

20. What charge will a protein have when the pH of its solution is below at - and above its pKa?
An enzyme that converts hydrogen peroxide to water plus oxygen.
Emulsification
Tryptophan
pH below positive charge; pH at no charge; pH above negative charge

21. How does HPLC differ from FPLC?
Fatty Acid and Alcohol
HPLC has higher pressure than FPLC
Degradation of protein and production of acid from sugar at the same time.
Glycosides of anthocyanidins

22. Name three effects of protein denaturation.
D: None of the above
Four
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Prolamines

23. What metabolic end product does the Voges-Proskauer test detect?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Linoleic Acid
Fructose
Acetoin

24. What is the main class of color compounds found in raspberries?
Initiation - Propagation - Termination
Acsulfame-K - Saccharin - Cyclamate - Aspartame
V=IR and P=VI or I x I x are
Anthocyanins

25. Name the most common functional property of phospholipids in food systems.
NaCl (it dissociated to a 2M solution)
Emulsification
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
.05

26. Name 3 factors influencing the rate of lipid oxidation in foods.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Pheophytin forms
Non-protein nitrogen

27. How many polypeptide chains make up an antibody?
Degradation of protein and production of acid from sugar at the same time.
Four
Thermus Aqauticus
Ammonia - Water - Carbon Dioxide

28. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
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.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Milk
Water

29. How can a molecular weight of protein - DNA - and RNA be determined?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Lycopenes
Tryptophan
Parabens

30. What does HLB stand for and What does a high and low HLB value indicate?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Olive Green
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.
Emulsoids

31. What are colloids that are stabilized by a layer of solvation called?
Prolamines
Emulsoids
Pectin Esterase - Polygalacturonase - Pectin Layase
Pectin Esterase - Polygalacturonase - Pectin Layase

32. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
pH 3-5
Plasmids
Troponins and Tropomyosin
Pectin Esterase

33. What are the fructose contents in commercial HFCS products.
Water
Racemic Mixture
45% - 52% - 90%
Bitter

34. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
RNA transcribed to DNA
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Lamellar; Hexagonal I - II; Cubic
Capsaicin

35. At what pH is benzoic acid most effective?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
pH 3-5
2.5
45% - 52% - 90%

36. Name three nonpolar polar - and charged amino acids.
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Anthocyanins
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Gossypol (it is removed during the oil refining process)

37. Is a disaccharide
Sucrose
Whole Milk
DNA transferred by cell to cell contact (bacterial sex).
Troponins and Tropomyosin

38. Will lipid oxidation be higher at a water activity of .05 or .5?
Fructose
Lysine - Arginine - and Histidine
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
.05

39. 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
Capsaicin
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
D: None of the above
Pheophytin forms

40. Is a disaccharide
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Pheophytia does not have magnesium in porphyrin ring.
pH 3-5
Sucrose

41. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Orange Juice
Cis
Daminozide
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

42. Are sorbitol and mannitol sweet?
Four
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Yes

43. What are the three stages of oxidative rancidity?
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
Pheophytin forms
pH 3-5
Initiation - Propagation - and Termination

44. What does Acid Degree Value measure and how is it measured?
.05
Prolamines
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Glycosides of anthocyanidins

45. What are the primary secondary - tertiary - and quaternary structures?
Erythorbic Acid
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 methylesterase & polygalacturonase
Pectin Esterase - Polygalacturonase - Pectin Layase

46. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Negative log of the hydrogen concentration (mol/l).
Acetoin
Carrageenan

47. What are proteins which are soluble in 50-80% ethanol known as?
Tryptophan
Prolamines
Daminozide
Carmelization and Maillard

48. What two common compounds are used together as an antioxidative system?
Yes
Ascorbic Acid and Citric Acid
Racemic Mixture
Whole Milk

49. Name 5 proteins with good foaming properties.
Polyphenol Oxidase
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.
Carmelization and Maillard
.05

50. What is a polymorphism?
Initiation - Propagation - Termination
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Primary butyric acid also caproic acid.