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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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1. What is the enzyme responsible for browning in apples and lettuce?
Onions ( or leeks)
Polyphenol Oxidase
Initiation - Propagation - and Termination
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.

2. Is a disaccharide
Sucrose
Pheophytia does not have magnesium in porphyrin ring.
pH 3-5
Fructose

3. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
It explodes
RNA transcribed to DNA
Osmosis
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

4. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
14
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

5. 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.
.05
Sweet - Salty - Sour - and Bitter
Polyphenols

6. What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
Initiation - Propagation - Termination
Phenylketonuria
Negative log of the hydrogen concentration (mol/l).

7. Will lipid oxidation be higher at a water activity of .05 or .5?
Anthocyanins
Initiation - Propagation - and Termination
Anomeric
.05

8. Match the number of carbon atoms with the common name of these saturated fatty acids. Carbon #: 4:0 10:0 - 12:0 -14:0 - 16:0 - 18:0Common Name: Myristic - Butyric - Capric - Lauric - Stearic - Palmitic
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Pectin methyl esterase or galacturonase
Daminozide
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

9. What is the name given to a mixture of equal parts of Darel Lisomers?
Whole Milk
Racemic Mixture
Plasmids
Nucleation or crystal formation and crystal growth.

10. Will lipid oxidation be higher at a water activity of .05 or .5?
.05
Ascorbic Acid and Citric Acid
DNA transferred by cell to cell contact (bacterial sex).
Fructose

11. How many polypeptide chains make up an antibody?
Cis
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Four
Covalent (strongest) and Hydrophobic (Weakest)

12. Name 5 chelating agents used in the food industry.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Aspartic Acid and Phenylalanine
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Lipid oxidation

13. What does Acid Degree 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.
Thamautin
D: None of the above
Plasmids

14. In what food is butyric acid typically found?
.05 M HCL
Gliadins and Glutenins
Milk
Fat Oxidation

15. How do sodium chloride and sucrose affect foam stability?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Pectins
Sodium bicarbonate generates CO2
Oil in Water

16. What are the fructose contents in commercial HFCS products.
45% - 52% - 90%
Emulsoids
Phenylketonuria
No

17. 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
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Racemic Mixture

18. What is the main class of color compounds found in raspberries?
Racemic Mixture
Anomeric
Anthocyanins
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

19. What is the structural difference between chlorophyll and pheophytia?
Pheophytia does not have magnesium in porphyrin ring.
Parabens
Erythorbic Acid
Anthocyanins

20. Which two amino acids is the aspartame derived from?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Emulsoids
Water
Aspartic Acid and Phenylalanine

21. What is surimi?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Plasmids
Pectins
A concentrate of microfibrillar proteins of fish muscle.

22. What is the Peroxide Value a measure of?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
20 carbons and 4 double bonds
ERH=100 x Aw
Fat Oxidation

23. What is the main class of color compounds found in raspberries?
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
14
Water
Anthocyanins

24. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
Two aldehydes
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Bitter
Thamautin

25. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Pectin Esterase
A concentrate of microfibrillar proteins of fish muscle.

26. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Non-protein nitrogen
Thamautin
Anomeric
Orange Juice

27. How many carbon atoms are there in the fatty acid myristic acid?
Pectin methyl esterase or galacturonase
Polyphenol Oxidase
14
Olive Green

28. How does ERH relate to water activity?
Blue pigment in flowers
A concentrate of microfibrillar proteins of fish muscle.
Erythorbic Acid
ERH=100 x Aw

29. How does HPLC differ from FPLC?
HPLC has higher pressure than FPLC
Sodium chloride reduces foam stability and sucrose improves foam stability.
Pheophytia does not have magnesium in porphyrin ring.
Pectin methylesterase & polygalacturonase

30. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Tryptophan
Bitter
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

31. What does MSG stand for?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Water
Pectins
Monosodium Glutamate

32. What does the iodine value measure and how is it measured?
Yellow
An enzyme that converts hydrogen peroxide to water plus oxygen.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin methylesterase & polygalacturonase

33. What pigment was first designated as anthocyanins?
Olive Green
Blue pigment in flowers
Daminozide
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

34. What is the structural difference between chlorophyll and chlocophyllide?
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Yes
Chlocophyllide does not have a phytoltail
The speed of a molecule is proportional to the surrounding voltage gradient.

35. Waxes are composed of what two basic chemical entities?
Pectin methylesterase & polygalacturonase
Fatty Acid (Ester linked) to Fatty Alcohol
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Cis

36. What does HLB stand for and What does a high and low HLB value indicate?
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
Pheophytin forms
Troponins and Tropomyosin

37. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Thickener in foods
Glycosides of anthocyanidins
Phenylketonuria
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls

38. What ketohexose is most significant to food chemists?
Pheophytin forms
Fructose
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.

39. How many carbon atoms and how many double bonds are there in arachidonic acid?
Sucrose
Thermus Aqauticus
20 carbons and 4 double bonds
Capsaicin

40. Name 5 proteins with good foaming properties.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
RNA transcribed to DNA
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.
Polyphenol Oxidase

41. How can a molecular weight of protein - DNA - and RNA be determined?
Initiation - Propagation - and Termination
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Pectin methylesterase & polygalacturonase

42. Name three nonpolar polar - and charged amino acids.
20 carbons and 4 double bonds
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
45% - 52% - 90%
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

43. Name 3 factors influencing the rate of lipid oxidation in foods.
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Pectin methyl esterase or galacturonase
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

44. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Carrageenan
Onions ( or leeks)
Fructose

45. 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?
Aspartic Acid and Phenylalanine
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Lycopenes
Lamellar; Hexagonal I - II; Cubic

46. What are two common reducing agents that break disulfide bonds in proteins?
Two aldehydes
Lysine - Arginine - and Histidine
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)

47. 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?
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.
It explodes
Lycopenes
Thamautin

48. Is a disaccharide
1 - 3 - 7-trimethylxanthine
pH below positive charge; pH at no charge; pH above negative charge
14
Sucrose

49. What metabolic end product does the Voges-Proskauer test detect?
Osmosis
Carmelization and Maillard
Gliadins and Glutenins
Acetoin

50. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
Prolamines
Pectin methyl esterase or galacturonase
NaCl (it dissociated to a 2M solution)
Daminozide