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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. How does HPLC differ from FPLC?
Osmosis
HPLC has higher pressure than FPLC
Initiation - Propagation - and Termination
Thermus Aqauticus

2. What happens to chlorophyll on heating?
Initiation - Propagation - and Termination
Pheophytin forms
Polyphenol Oxidase
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

3. 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?
Polyphenol Oxidase
An enzyme that converts hydrogen peroxide to water plus oxygen.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Negative log of the hydrogen concentration (mol/l).

4. Name 5 proteins with good foaming properties.
1 - 3 - 7-trimethylxanthine
Phenylketonuria
Pheophytia does not have magnesium in porphyrin ring.
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.

5. At low water activity What is the main deteriorative concern?
Pectin methyl esterase or galacturonase
Lipid oxidation
2.5
Chlocophyllide does not have a phytoltail

6. What does the saponification value measure and how is it measured?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Thamautin
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

7. What does Acid Degree Value measure and how is it measured?
Thamautin
Aspartic Acid and Phenylalanine
Yellow
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

8. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
NaCl (it dissociated to a 2M solution)
Anthocyanins
Pheophytin forms
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.

9. What is acid proteolysis?
Four
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Degradation of protein and production of acid from sugar at the same time.
Polyphenol Oxidase

10. How does HPLC differ from FPLC?
Ascorbic Acid and Citric Acid
pH 3-5
HPLC has higher pressure than FPLC
pH below positive charge; pH at no charge; pH above negative charge

11. Name one way foam stability can be assessed.
Tryptophan
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.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Acsulfame-K - Saccharin - Cyclamate - Aspartame

12. Peptide bond formation results in the formation of what secondary compound?
Water
Fat Oxidation
Covalent (strongest) and Hydrophobic (Weakest)
V=IR and P=VI or I x I x are

13. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Bitter
Parabens
Water
No

14. Name 5 proteins with good foaming properties.
Phenylketonuria
2.5
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.
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.

15. Name two non-enzymatic browning reactions.
Phenophylin
Carmelization and Maillard
Chitin
Gliadins and Glutenins

16. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Sodium bicarbonate generates CO2
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Yellow

17. What compounds oxidize to form brown color in fruits and vegetables?
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Non-protein nitrogen
Polyphenols
V=IR and P=VI or I x I x are

18. What pigment was first designated as anthocyanins?
Sucrose
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Blue pigment in flowers
Fat Oxidation

19. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Chitin
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.
Racemic Mixture
Water

20. 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
pH below positive charge; pH at no charge; pH above negative charge
D: None of the above
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Fat Oxidation

21. What are the three main steps in the autooxidation of lipids?
Initiation - Propagation - Termination
Fat Oxidation
Ascorbic Acid and Citric Acid
1 - 3 - 7-trimethylxanthine

22. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Anomeric
ERH=100 x Aw
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
They act as catalysts - speeding the polymerization of acrylamide.

23. How many carbon atoms are there in the fatty acid myristic 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.
Emulsoids
14
Lipase

24. What are the three main steps in the autooxidation of lipids?
Carmelization and Maillard
Two aldehydes
Initiation - Propagation - Termination
Linoleic Acid

25. At low water activity What is the main deteriorative concern?
Carmelization and Maillard
Lipid oxidation
Troponins and Tropomyosin
Milk

26. What does Reichert-Meissert Number measure?
HPLC has higher pressure than FPLC
RNA transcribed to DNA
Primary butyric acid also caproic acid.
Polyphenols

27. What are the fructose contents in commercial HFCS products.
Fructose
Fatty Acid and Alcohol
45% - 52% - 90%
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.

28. What two common compounds are used together as an antioxidative system?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Phenylketonuria
Ascorbic Acid and Citric Acid
It explodes

29. What is the geometric configuration of double bonds in most natural fatty acids?
Cis
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
Carrageenan
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

30. What are the three stages of oxidative rancidity?
Initiation - Propagation - and Termination
Daminozide
Phenylketonuria
Acsulfame-K - Saccharin - Cyclamate - Aspartame

31. Does kosmotrophil ion discourage water structure?
Osmosis
Browning of freshly cut surfaces of fruits and vegetables.
RNA transcribed to DNA
No

32. Define molarity molality - and normality.
Polyphenols
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
45% - 52% - 90%
Non-protein nitrogen

33. What is the main class of color compounds found in raspberries?
It explodes
Anthocyanins
Pectin Esterase - Polygalacturonase - Pectin Layase
Blue pigment in flowers

34. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bitter
Bright green
Lipid oxidation
Daminozide

35. What is the acid present in fish oil?
Arachidonic Acid
An enzyme that converts hydrogen peroxide to water plus oxygen.
Linoleic Acid
Osmosis

36. What does HLB stand for and What does a high and low HLB value indicate?
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Primary butyric acid also caproic acid.
Four
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.

37. What is the chemical nomenclature for caffeine?
Troponins and Tropomyosin
Yellow
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
1 - 3 - 7-trimethylxanthine

38. Name the strongest biochemical bond and the weakest biochemical bond.
Fat Oxidation
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.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Covalent (strongest) and Hydrophobic (Weakest)

39. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Fatty Acid and Alcohol
Thickener in foods
Four
Yellow

40. Name two reasons why fats are hydrogenated.
Ammonia - Water - Carbon Dioxide
Phenylketonuria
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Fructose

41. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
ERH=100 x Aw
Emulsification
Capsaicin
ERH=100 x Aw

42. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Emulsification
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
RNA transcribed to DNA

43. What is catalase?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Parabens
Chitin
An enzyme that converts hydrogen peroxide to water plus oxygen.

44. What are two common reducing agents that break disulfide bonds in proteins?
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.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Fatty Acid and Alcohol
Emulsoids

45. How do sodium chloride and sucrose affect foam stability?
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Sodium chloride reduces foam stability and sucrose improves foam stability.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

46. What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
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
Ascorbic Acid and Citric Acid
Lycopenes

47. What is the name given to a mixture of equal parts of Darel Lisomers?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Phenophylin
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Racemic Mixture

48. Name three effects of protein denaturation.
ERH=100 x Aw
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Lipase
Polyphenoloxidase

49. Will lipid oxidation be higher at a water activity of .05 or .5?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Speed of Light
Fructose
.05

50. During freezing What are the two stages in the crystallization process?
Orange Juice
Nucleation or crystal formation and crystal growth.
pH 3-5
V=IR and P=VI or I x I x are