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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 name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
2.5
Plasmids

2. What is an isomer that is cheaper than Vitamin C?
Phenophylin
Plasmids
Degradation of protein and production of acid from sugar at the same time.
Erythorbic Acid

3. What is the Peroxide Value a measure of?
Browning of freshly cut surfaces of fruits and vegetables.
Anthocyanins
Fat Oxidation
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

4. What are proteins which are soluble in 50-80% ethanol known as?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
.05
Prolamines

5. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Polyphenol Oxidase
Water
NaCl (it dissociated to a 2M solution)

6. Name 3 chemical agents capable of denaturing proteins.
Fat Oxidation
Aspartic Acid and Phenylalanine
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Chitin

7. What is Carboxy-methyl cellulose often used for?
Linoleic Acid
Two aldehydes
ERH=100 x Aw
Thickener in foods

8. What are the three main steps in the autooxidation of lipids?
Initiation - Propagation - Termination
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Olive Green

9. What is the Peroxide Value a measure of?
Fat Oxidation
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Blue pigment in flowers
Yes

10. What compounds oxidize to form brown color in fruits and vegetables?
Polyphenols
Lipid oxidation
Fat Oxidation
14

11. In the enzyme Taq Polymerase What does Taq stand for?
Plasmids
Thermus Aqauticus
14
Gossypol (it is removed during the oil refining process)

12. What is the protein efficiency ratio (PER) of casein?
Bitter
Osmosis
pH below positive charge; pH at no charge; pH above negative charge
2.5

13. What does the acronym NPN stand for?
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Non-protein nitrogen
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

14. What are the fructose contents in commercial HFCS products.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Anthocyanins
45% - 52% - 90%

15. What is the structural difference between chlorophyll and pheophytia?
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pheophytia does not have magnesium in porphyrin ring.
Ammonia - Water - Carbon Dioxide
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

16. What are proteins which are soluble in 50-80% ethanol known as?
Yes
Prolamines
Troponins and Tropomyosin
Emulsification

17. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
.05 M HCL
Tryptophan
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Ascorbic Acid and Citric Acid

18. What two types of compounds are joined with an ester bond to make a wax?
Fatty Acid and Alcohol
Phenophylin
Anthocyanins
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

19. Name 5 chelating agents used in the food industry.
Yellow
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Thamautin

20. What are soluble polymers of anhydro-galacturonic acid and its esters called?
.05 M HCL
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Emulsoids
Pectins

21. What are the three stages of oxidative rancidity?
Initiation - Propagation - and Termination
Parabens
Lamellar; Hexagonal I - II; Cubic
Onions ( or leeks)

22. What is the name of the degradation compound of chlorophyll?
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.
Blue pigment in flowers
Thamautin
Phenophylin

23. What two enzymes degrade pectic substances?
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.
Pectin methylesterase & polygalacturonase
Lysine - Arginine - and Histidine
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

24. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Polyphenol Oxidase
Browning of freshly cut surfaces of fruits and vegetables.
It explodes
Yellow

25. At low water activity What is the main deteriorative concern?
Initiation - Propagation - and Termination
Onions ( or leeks)
Monosodium Glutamate
Lipid oxidation

26. Alar is the trade name for what chemical compound?
RNA transcribed to DNA
Daminozide
.05 M HCL
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

27. Contains the lowest content of water
Lamellar; Hexagonal I - II; Cubic
Whole Milk
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
pH below positive charge; pH at no charge; pH above negative charge

28. How is pH defined?
Acetoin
Negative log of the hydrogen concentration (mol/l).
2.5
pH below positive charge; pH at no charge; pH above negative charge

29. What is the major color compound in tomatoes?
Lycopenes
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
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

30. What does the iodine value measure and how is it measured?
Oil in Water
Polyphenol Oxidase
Polyphenol Oxidase
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

31. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
NaCl (it dissociated to a 2M solution)
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

32. Are sorbitol and mannitol sweet?
Initiation - Propagation - Termination
Yes
1 - 3 - 7-trimethylxanthine
Chitin

33. What is the fundamental driving of electrophoresis?
The speed of a molecule is proportional to the surrounding voltage gradient.
Non-protein nitrogen
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Yes

34. What are the primary secondary - tertiary - and quaternary structures?
Initiation - Propagation - and Termination
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)
Negative log of the hydrogen concentration (mol/l).

35. What is the winterization process for an oil?
Covalent (strongest) and Hydrophobic (Weakest)
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Sucrose

36. What happens to chlorophyll on heating?
Pheophytin forms
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
45% - 52% - 90%
Gossypol (it is removed during the oil refining process)

37. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Lysine - Arginine - and Histidine
Pectin Esterase
Linoleic Acid
Aspartic Acid and Phenylalanine

38. Name three factors useful in controlling enzyme activity.
Pheophytia does not have magnesium in porphyrin ring.
Initiation - Propagation - Termination
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Fat Oxidation

39. What two types of compounds are joined with an ester bond to make a wax?
Initiation - Propagation - Termination
Fatty Acid and Alcohol
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
14

40. What is the geometric configuration of double bonds in most natural fatty acids?
Fructose
Non-protein nitrogen
Cis
Emulsoids

41. At what pH is benzoic acid most effective?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Pectin methyl esterase or galacturonase
Parabens
pH 3-5

42. What is surimi?
A concentrate of microfibrillar proteins of fish muscle.
Orange Juice
Onions ( or leeks)
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

43. Name 3 factors influencing the rate of lipid oxidation in foods.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Nucleation or crystal formation and crystal growth.
Whole Milk
DNA transferred by cell to cell contact (bacterial sex).

44. How do sodium chloride and sucrose affect foam stability?
1 - 3 - 7-trimethylxanthine
Fructose
Sodium chloride reduces foam stability and sucrose improves foam stability.
An enzyme that converts hydrogen peroxide to water plus oxygen.

45. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Carrageenan
Fatty Acid (Ester linked) to Fatty Alcohol
Fatty Acid and Alcohol

46. 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
Non-protein nitrogen
Nucleation or crystal formation and crystal growth.
Browning of freshly cut surfaces of fruits and vegetables.
Aspartic Acid and Phenylalanine

47. What two enzymes degrade pectic substances?
Pectin methylesterase & polygalacturonase
Bright green
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Monosodium Glutamate

48. What does Reichert-Meissert Number measure?
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Chlocophyllide does not have a phytoltail
Sweet - Salty - Sour - and Bitter
Primary butyric acid also caproic acid.

49. Name 3 chemical agents capable of denaturing proteins.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
ERH=100 x Aw
Lipid oxidation
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

50. What is a polymorphism?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
20 carbons and 4 double bonds
pH 3-5