Test your basic knowledge |

Food Chemistry

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. Name 3 chemical agents capable of denaturing proteins.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Browning of freshly cut surfaces of fruits and vegetables.
Fat Oxidation
Two aldehydes

2. Name 4 advantages of using enzymes in food processing.
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
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Prolamines
Erythorbic Acid

3. How many polypeptide chains make up an antibody?
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.
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
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Four

4. What is a polymorphism?
Two aldehydes
D: None of the above
Carmelization and Maillard
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

5. What is the fundamental driving of electrophoresis?
Lipase
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Anthocyanins
The speed of a molecule is proportional to the surrounding voltage gradient.

6. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Pectin methyl esterase or galacturonase
NaCl (it dissociated to a 2M solution)
Fat Oxidation

7. In genetics What is conjugation?
Chlocophyllide does not have a phytoltail
Fat Oxidation
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
DNA transferred by cell to cell contact (bacterial sex).

8. Name two reasons why fats are hydrogenated.
Gossypol (it is removed during the oil refining process)
The speed of a molecule is proportional to the surrounding voltage gradient.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Anthocyanins

9. Alar is the trade name for what chemical compound?
Daminozide
No
Covalent (strongest) and Hydrophobic (Weakest)
Lamellar; Hexagonal I - II; Cubic

10. What is an isomer that is cheaper than Vitamin C?
Lipase
Arachidonic Acid
Thickener in foods
Erythorbic Acid

11. What is the geometric configuration of double bonds in most natural fatty acids?
Water
pH 3-5
Browning of freshly cut surfaces of fruits and vegetables.
Cis

12. What is the Peroxide Value a measure of?
Fructose
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Onions ( or leeks)
Fat Oxidation

13. What two enzymes degrade pectic substances?
DNA transferred by cell to cell contact (bacterial sex).
Pectin methylesterase & polygalacturonase
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Yes

14. How can a molecular weight of protein - DNA - and RNA be determined?
Chlocophyllide does not have a phytoltail
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Troponins and Tropomyosin
Glycosides of anthocyanidins

15. What are the three stages of oxidative rancidity?
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Polyphenol Oxidase
Initiation - Propagation - and Termination
Degradation of protein and production of acid from sugar at the same time.

16. During freezing What are the two stages in the crystallization process?
Nucleation or crystal formation and crystal growth.
D: None of the above
Daminozide
Polyphenol Oxidase

17. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Pheophytin forms
Fatty Acid and Alcohol
Onions ( or leeks)
Carrageenan

18. How many carbon atoms are there in the fatty acid myristic acid?
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
14
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
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.

19. What is the chemical nature of anthocyanins?
Daminozide
Glycosides of anthocyanidins
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Chitin

20. What toxic pigment is found in cottonseed endosperm?
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
Gossypol (it is removed during the oil refining process)
Olive Green
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.

21. How can a molecular weight of protein - DNA - and RNA be determined?
Two aldehydes
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Yes
Fatty Acid (Ester linked) to Fatty Alcohol

22. 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?
Pectin methyl esterase or galacturonase
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
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
Browning of freshly cut surfaces of fruits and vegetables.

23. 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?
Lamellar; Hexagonal I - II; Cubic
.05
It explodes
Lipid oxidation

24. Name two main gluten proteins.
Milk
Gliadins and Glutenins
Thickener in foods
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.

25. What happens to chlorophyll on heating?
Pectin Esterase
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.
Pheophytin forms
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)

26. 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
Bright green
ERH=100 x Aw
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
pH below positive charge; pH at no charge; pH above negative charge

27. Name 3 chemical agents capable of denaturing proteins.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Speed of Light

28. What ketohexose is most significant to food chemists?
Phenophylin
Fructose
14
Bitter

29. When heated ammonium bicarbonate decomposes to form what end products?
Ammonia - Water - Carbon Dioxide
Pectin methylesterase & polygalacturonase
Anomeric
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

30. Name two reasons why fats are hydrogenated.
V=IR and P=VI or I x I x are
Daminozide
Anthocyanins
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.

31. What are the limiting amino acids in corn - potato - and green peas?
Chlocophyllide does not have a phytoltail
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

32. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Degradation of protein and production of acid from sugar at the same time.
Carmelization and Maillard
Onions ( or leeks)
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

33. Name 5 proteins with good foaming properties.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Troponins and Tropomyosin
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
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.

34. Does kosmotrophil ion discourage water structure?
DNA transferred by cell to cell contact (bacterial sex).
Milk
Monosodium Glutamate
No

35. When heated ammonium bicarbonate decomposes to form what end products?
Ammonia - Water - Carbon Dioxide
Cis
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

36. What toxic pigment is found in cottonseed endosperm?
Pheophytin forms
Gossypol (it is removed during the oil refining process)
Acetoin
Cis

37. What does the saponification value measure and how is it measured?
.05 M HCL
Speed of Light
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

38. What are the three main steps in the autooxidation of lipids?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
pH 3-5
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.
Initiation - Propagation - Termination

39. What is the name of the degradation compound of chlorophyll?
Pectin Esterase
Phenophylin
Milk
Ammonia - Water - Carbon Dioxide

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
Erythorbic Acid
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.
Water
Non-protein nitrogen

41. Name 3 factors influencing the rate of lipid oxidation in foods.
HPLC has higher pressure than FPLC
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
NaCl (it dissociated to a 2M solution)
Chlocophyllide does not have a phytoltail

42. Name two non-enzymatic browning reactions.
Polyphenol Oxidase
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Tryptophan
Carmelization and Maillard

43. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
Two aldehydes
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Fat Oxidation
ERH=100 x Aw

44. What is the enzyme that softens tomatoes?
Aspartic Acid and Phenylalanine
Parabens
Chitin
Pectin Esterase

45. What are soluble polymers of anhydro-galacturonic acid and its esters called?
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
20 carbons and 4 double bonds
Pectins
Troponins and Tropomyosin

46. Name two main gluten proteins.
Gliadins and Glutenins
Monosodium Glutamate
Water
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

47. How do sodium chloride and sucrose affect foam stability?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Prolamines
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Prolamines

48. What is the enzyme that softens tomatoes?
Pectin Esterase
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.
Browning of freshly cut surfaces of fruits and vegetables.
Erythorbic Acid

49. Will lipid oxidation be higher at a water activity of .05 or .5?
Aspartic Acid and Phenylalanine
Polyphenols
They act as catalysts - speeding the polymerization of acrylamide.
.05

50. At what pH is benzoic acid most effective?
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Initiation - Propagation - and Termination
pH 3-5
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants