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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. How is pH defined?
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
Negative log of the hydrogen concentration (mol/l).
Emulsoids
Lysine - Arginine - and Histidine

2. Name one way foam stability can be assessed.
Chitin
Blue pigment in flowers
Non-protein nitrogen
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.

3. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
HPLC has higher pressure than FPLC
Lamellar; Hexagonal I - II; Cubic
Pheophytin forms
Phenylketonuria

4. How can a molecular weight of protein - DNA - and RNA be determined?
Oil in Water
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Thickener in foods
Lipid oxidation

5. What is the protein efficiency ratio (PER) of casein?
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Yellow
2.5
Tryptophan

6. How many polypeptide chains make up an antibody?
Four
Linoleic Acid
Sodium chloride reduces foam stability and sucrose improves foam stability.
Bright green

7. Will lipid oxidation be higher at a water activity of .05 or .5?
Degradation of protein and production of acid from sugar at the same time.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams 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.
.05

8. Define molarity molality - and normality.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Gossypol (it is removed during the oil refining process)
Chitin
Polyphenol Oxidase

9. 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?
No
.05 M HCL
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin methylesterase & polygalacturonase

10. What are the three stages of oxidative rancidity?
D: None of the above
Primary butyric acid also caproic acid.
Initiation - Propagation - and Termination
Acetoin

11. Name two reasons why fats are hydrogenated.
Thamautin
Polyphenol Oxidase
Fructose
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

12. What is the winterization process for an oil?
They act as catalysts - speeding the polymerization of acrylamide.
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Gliadins and Glutenins
Pectins

13. What are colloids that are stabilized by a layer of solvation called?
Emulsoids
Gliadins and Glutenins
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Thickener in foods

14. Are sorbitol and mannitol sweet?
Yes
Yellow
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Carmelization and Maillard

15. What is the enzyme responsible for browning in apples and lettuce?
Anomeric
.05 M HCL
Polyphenol Oxidase
Daminozide

16. How is pH defined?
Negative log of the hydrogen concentration (mol/l).
14
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Nucleation or crystal formation and crystal growth.

17. 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
Lysine - Arginine - and Histidine
D: None of the above
Gossypol (it is removed during the oil refining process)
Bitter

18. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
Osmosis
Carmelization and Maillard
Sweet - Salty - Sour - and Bitter

19. What is acid proteolysis?
Yes
Acetoin
Degradation of protein and production of acid from sugar at the same time.
Cis

20. What is the main class of color compounds found in raspberries?
Degradation of protein and production of acid from sugar at the same time.
Anthocyanins
Racemic Mixture
Nucleation or crystal formation and crystal growth.

21. Alar is the trade name for what chemical compound?
Osmosis
Ascorbic Acid and Citric Acid
Fatty Acid (Ester linked) to Fatty Alcohol
Daminozide

22. Name 3 factors influencing the rate of lipid oxidation in foods.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
pH 3-5
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

23. What is acid proteolysis?
Degradation of protein and production of acid from sugar at the same time.
Initiation - Propagation - and Termination
Sodium chloride reduces foam stability and sucrose improves foam stability.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

24. What is the enzyme that softens tomatoes?
Pectin Esterase
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
They act as catalysts - speeding the polymerization of acrylamide.
Emulsification

25. What does the saponification 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.
Polyphenoloxidase
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Degradation of protein and production of acid from sugar at the same time.

26. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Thamautin
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Anomeric

27. What is surimi?
Capsaicin
Browning of freshly cut surfaces of fruits and vegetables.
Polyphenol Oxidase
A concentrate of microfibrillar proteins of fish muscle.

28. What is the Peroxide Value a measure of?
ERH=100 x Aw
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Osmosis
Fat Oxidation

29. What toxic pigment is found in cottonseed endosperm?
Ammonia - Water - Carbon Dioxide
Gossypol (it is removed during the oil refining process)
Yes
Pectins

30. During freezing What are the two stages in the crystallization process?
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Bright green
pH 3-5
Nucleation or crystal formation and crystal growth.

31. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Thamautin
Fructose
Sodium chloride reduces foam stability and sucrose improves foam stability.
Oil in Water

32. What enzyme causes hyrolytic rancidity in milk?
Water
Lipase
Covalent (strongest) and Hydrophobic (Weakest)
Sucrose

33. Will lipid oxidation be higher at a water activity of .05 or .5?
.05
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Acsulfame-K - Saccharin - Cyclamate - Aspartame

34. In the enzyme Taq Polymerase What does Taq stand for?
Polyphenols
Ascorbic Acid and Citric Acid
Prolamines
Thermus Aqauticus

35. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Carrageenan
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.
Milk
Pheophytia does not have magnesium in porphyrin ring.

36. Waxes are composed of what two basic chemical entities?
Gossypol (it is removed during the oil refining process)
.05 M HCL
Fatty Acid (Ester linked) to Fatty Alcohol
Pectin Esterase - Polygalacturonase - Pectin Layase

37. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Onions ( or leeks)
Milk
Pectin Esterase
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

38. Is a disaccharide
Cis
Sucrose
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.

39. What is the fundamental driving of electrophoresis?
Water
Pheophytin forms
Initiation - Propagation - Termination
The speed of a molecule is proportional to the surrounding voltage gradient.

40. 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
Racemic Mixture
Daminozide
Pectin methylesterase & polygalacturonase

41. Peptide bond formation results in the formation of what secondary compound?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Water
Plasmids
Primary butyric acid also caproic acid.

42. What is an isomer that is cheaper than Vitamin C?
Lipid oxidation
Sucrose
Pectin methylesterase & polygalacturonase
Erythorbic Acid

43. Does kosmotrophil ion discourage water structure?
Polyphenol Oxidase
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Aspartic Acid and Phenylalanine
No

44. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Osmosis
RNA transcribed to DNA

45. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
Degradation of protein and production of acid from sugar at the same time.
.05
Negative log of the hydrogen concentration (mol/l).

46. What is the name of the degradation compound of chlorophyll?
Linoleic Acid
Phenophylin
Fat Oxidation
Ammonia - Water - Carbon Dioxide

47. What does the acronym NPN stand for?
Lycopenes
Covalent (strongest) and Hydrophobic (Weakest)
Initiation - Propagation - Termination
Non-protein nitrogen

48. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Bright green
Osmosis
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Pectin Esterase

49. Which two amino acids is the aspartame derived from?
Linoleic Acid
Lipid oxidation
Tryptophan
Aspartic Acid and Phenylalanine

50. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Four
Onions ( or leeks)
14