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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 name of the degradation compound of chlorophyll?
Phenophylin
Covalent (strongest) and Hydrophobic (Weakest)
No
Carrageenan

2. 20 grams of amylose is added to 80 grams of water in a bearker; the boiling point is measured with an ordinary mercury-in-glass thermometer. What is the observed boiling point of the material in the beaker?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Acetoin
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

3. 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?
Primary butyric acid also caproic acid.
Fatty Acid (Ester linked) to Fatty Alcohol
Ascorbic Acid and Citric Acid
It explodes

4. Name 3 factors influencing the consistency of commercial fats.
Water
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
pH 3-5
Pectin methyl esterase or galacturonase

5. What is the enzyme responsible for browning in apples and lettuce?
Degradation of protein and production of acid from sugar at the same time.
Fructose
Polyphenol Oxidase
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

6. What are two common reducing agents that break disulfide bonds in proteins?
Pheophytia does not have magnesium in porphyrin ring.
Pectins
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Troponins and Tropomyosin

7. Name three factors useful in controlling enzyme activity.
DNA transferred by cell to cell contact (bacterial sex).
45% - 52% - 90%
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls

8. Name two enzymes that are involved in softening fruits.
Erythorbic Acid
Pectin Esterase - Polygalacturonase - Pectin Layase
45% - 52% - 90%
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

9. What compounds oxidize to form brown color in fruits and vegetables?
Pheophytin forms
Primary butyric acid also caproic acid.
Polyphenols
Sodium chloride reduces foam stability and sucrose improves foam stability.

10. Name three effects of protein denaturation.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
An enzyme that converts hydrogen peroxide to water plus oxygen.
Thamautin
V=IR and P=VI or I x I x are

11. What is the Peroxide Value a measure of?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Phenophylin
Non-protein nitrogen
Fat Oxidation

12. During freezing What are the two stages in the crystallization process?
Nucleation or crystal formation and crystal growth.
2.5
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
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

13. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Oil in Water
Tryptophan
Fatty Acid and Alcohol
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

14. Name two main gluten proteins.
Gliadins and Glutenins
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
Monosodium Glutamate

15. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Oil in Water
Sodium chloride reduces foam stability and sucrose improves foam stability.
Ammonia - Water - Carbon Dioxide
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

16. What enzyme is most responsible for browning bananas?
Polyphenol Oxidase
Plasmids
Fructose
Pheophytin forms

17. In what food is butyric acid typically found?
They act as catalysts - speeding the polymerization of acrylamide.
Carrageenan
Milk
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

18. What happens to chlorophyll on heating?
Pheophytin forms
Cis
pH 3-5
Gossypol (it is removed during the oil refining process)

19. Name two reasons why fats are hydrogenated.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Emulsification
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Erythorbic Acid

20. Name the most common functional property of phospholipids in food systems.
Four
V=IR and P=VI or I x I x are
Linoleic Acid
Emulsification

21. 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
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Monosodium Glutamate
D: None of the above

22. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Onions ( or leeks)
Anomeric
Ammonia - Water - Carbon Dioxide
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

23. Name the two components that comprise the relaxing factor in muscle fibers.
pH below positive charge; pH at no charge; pH above negative charge
Troponins and Tropomyosin
pH 3-5
Pectins

24. Name three nonpolar polar - and charged amino acids.
Thamautin
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Sodium chloride reduces foam stability and sucrose improves foam stability.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

25. In genetics What is conjugation?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
D: None of the above
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
DNA transferred by cell to cell contact (bacterial sex).

26. Name two reasons why fats are hydrogenated.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Sucrose
Gliadins and Glutenins
Pectin Esterase

27. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
Capsaicin
Water
45% - 52% - 90%
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

28. What charge will a protein have when the pH of its solution is below at - and above its pKa?
HPLC has higher pressure than FPLC
Thamautin
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
pH below positive charge; pH at no charge; pH above negative charge

29. 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?
.05 M HCL
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
DNA transferred by cell to cell contact (bacterial sex).
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

30. Is a disaccharide
No
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Sucrose

31. What is the main class of color compounds found in raspberries?
Pectin methylesterase & polygalacturonase
NaCl (it dissociated to a 2M solution)
Emulsoids
Anthocyanins

32. At low water activity What is the main deteriorative concern?
Blue pigment in flowers
Lipid oxidation
Daminozide
Anthocyanins

33. What are the three main steps in the autooxidation of lipids?
Non-protein nitrogen
Initiation - Propagation - Termination
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

34. What is acid proteolysis?
Sweet - Salty - Sour - and Bitter
Degradation of protein and production of acid from sugar at the same time.
Water
Aspartic Acid and Phenylalanine

35. How many carbon atoms are there in the fatty acid myristic acid?
Cis
Lysine - Arginine - and Histidine
Glycosides of anthocyanidins
14

36. Name 5 proteins with good foaming properties.
Daminozide
Emulsification
Oil in Water
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.

37. What toxic pigment is found in cottonseed endosperm?
Gossypol (it is removed during the oil refining process)
Monosodium Glutamate
Erythorbic Acid
Troponins and Tropomyosin

38. How many carbon atoms and how many double bonds are there in arachidonic acid?
Polyphenoloxidase
Erythorbic Acid
DNA transferred by cell to cell contact (bacterial sex).
20 carbons and 4 double bonds

39. What does HLB stand for and What does a high and low HLB value indicate?
Anomeric
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Water
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.

40. Which of the following examples of browning is enzymatic in nature? 1. Browning of sugars as a result of heating 2. Browning of freshly cut surfaces of fruits and vegetables 3. Browning of bread during toasting 4. Browning of potato chips
Browning of freshly cut surfaces of fruits and vegetables.
Gliadins and Glutenins
Arachidonic Acid
45% - 52% - 90%

41. What does HLB stand for and What does a high and low HLB value indicate?
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
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.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
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.

42. What does Acid Degree Value measure and how is it measured?
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.
Lycopenes
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Four

43. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
.05 M HCL
V=IR and P=VI or I x I x are
Water
Bright green

44. Is a disaccharide
Sucrose
Sodium chloride reduces foam stability and sucrose improves foam stability.
Troponins and Tropomyosin
Nucleation or crystal formation and crystal growth.

45. Name one way foam stability can be assessed.
Pectin methylesterase & polygalacturonase
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.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Gossypol (it is removed during the oil refining process)

46. What is the name given to a mixture of equal parts of Darel Lisomers?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Yellow
Fructose
Racemic Mixture

47. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
It explodes
Yes
Thermus Aqauticus

48. Waxes are composed of what two basic chemical entities?
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.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Fatty Acid (Ester linked) to Fatty Alcohol
Sucrose

49. How do sodium chloride and sucrose affect foam stability?
Sodium chloride reduces foam stability and sucrose improves foam stability.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
14
Olive Green

50. What are proteins which are soluble in 50-80% ethanol known as?
Prolamines
Sweet - Salty - Sour - and Bitter
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls