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 two non-enzymatic browning reactions.
Carmelization and Maillard
Blue pigment in flowers
Thermus Aqauticus
Milk

2. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Yellow
Olive Green
It explodes
Erythorbic Acid

3. What enzyme is most responsible for browning bananas?
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Polyphenol Oxidase
Degradation of protein and production of acid from sugar at the same time.
Water

4. Name 4 advantages of using enzymes in food processing.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Lamellar; Hexagonal I - II; Cubic
Chitin
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

5. What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
Emulsification
Emulsoids
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

6. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
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.
Initiation - Propagation - Termination
Orange Juice
Oil in Water

7. How can a molecular weight of protein - DNA - and RNA be determined?
Capsaicin
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.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Prolamines

8. What is the chemical nature of anthocyanins?
Glycosides of anthocyanidins
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Linoleic Acid
Polyphenol Oxidase

9. What two types of compounds are joined with an ester bond to make a wax?
Fatty Acid and Alcohol
Water
DNA transferred by cell to cell contact (bacterial sex).
No

10. What are the four basic flavors perceived by the tongue?
Browning of freshly cut surfaces of fruits and vegetables.
Sweet - Salty - Sour - and Bitter
Whole Milk
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.

11. What does the iodine value measure and how is it measured?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin Esterase
Tryptophan

12. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Carmelization and Maillard
Pectins

13. Name 3 chemical agents capable of denaturing proteins.
Daminozide
Linoleic Acid
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Arachidonic Acid

14. In the enzyme Taq Polymerase What does Taq stand for?
Anthocyanins
Thermus Aqauticus
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)

15. What is the winterization process for an oil?
Bitter
Troponins and Tropomyosin
Oil in Water
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.

16. How is pH defined?
Negative log of the hydrogen concentration (mol/l).
Sucrose
Phenylketonuria
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

17. What is the fundamental driving of electrophoresis?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Yes
Primary butyric acid also caproic acid.
The speed of a molecule is proportional to the surrounding voltage gradient.

18. Name 5 chelating agents used in the food industry.
Thamautin
Emulsification
Plasmids
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

19. What does the acronym NPN stand for?
Non-protein nitrogen
Degradation of protein and production of acid from sugar at the same time.
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.
Covalent (strongest) and Hydrophobic (Weakest)

20. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Tryptophan
V=IR and P=VI or I x I x are
Oil in Water
Osmosis

21. Name the strongest biochemical bond and the weakest biochemical bond.
Osmosis
Troponins and Tropomyosin
Covalent (strongest) and Hydrophobic (Weakest)
Yes

22. Alar is the trade name for what chemical compound?
The speed of a molecule is proportional to the surrounding voltage gradient.
NaCl (it dissociated to a 2M solution)
Daminozide
Thickener in foods

23. What are the three main steps in the autooxidation of lipids?
V=IR and P=VI or I x I x are
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.
Oil in Water
Initiation - Propagation - Termination

24. What are the primary secondary - tertiary - and quaternary structures?
DNA transferred by cell to cell contact (bacterial sex).
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
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.
An enzyme that converts hydrogen peroxide to water plus oxygen.

25. What is the chemical nomenclature for caffeine?
Bright green
1 - 3 - 7-trimethylxanthine
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Ascorbic Acid and Citric Acid

26. Food additive that could be used to prevent cocoa particles from settling in chocolate milk
Browning of freshly cut surfaces of fruits and vegetables.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Carrageenan
Emulsification

27. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Acetoin
Aspartic Acid and Phenylalanine
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Nucleation or crystal formation and crystal growth.

28. What is the geometric configuration of double bonds in most natural fatty acids?
Oil in Water
pH below positive charge; pH at no charge; pH above negative charge
Water
Cis

29. What chemical compound is responsible for the 'hot' principle of jalepeno peppers?
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
It explodes
An enzyme that converts hydrogen peroxide to water plus oxygen.
Capsaicin

30. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Pectin Esterase - Polygalacturonase - Pectin Layase
Glycosides of anthocyanidins
Oil in Water
Plasmids

31. What is Carboxy-methyl cellulose often used for?
Nucleation or crystal formation and crystal growth.
An enzyme that converts hydrogen peroxide to water plus oxygen.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Thickener in foods

32. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Pectin methylesterase & polygalacturonase
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Acetoin

33. Name 3 factors influencing the consistency of commercial fats.
Covalent (strongest) and Hydrophobic (Weakest)
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Pheophytin forms
Onions ( or leeks)

34. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Polyphenol Oxidase
Oil in Water
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Phenylketonuria

35. Does kosmotrophil ion discourage water structure?
No
Yellow
Chitin
pH 3-5

36. What is the acid present in fish oil?
pH 3-5
Arachidonic Acid
Capsaicin
Phenophylin

37. What does Acid Degree Value measure and how is it measured?
Pectin Esterase - Polygalacturonase - Pectin Layase
Pectin Esterase - Polygalacturonase - Pectin Layase
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

38. Name the three positively charged amino acids.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin Esterase - Polygalacturonase - Pectin Layase
Lysine - Arginine - and Histidine
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

39. What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Pheophytia does not have magnesium in porphyrin ring.
Erythorbic Acid
Parabens

40. How does ERH relate to water activity?
Two aldehydes
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.
Onions ( or leeks)

41. What is the name of the degradation compound of chlorophyll?
Thamautin
Lamellar; Hexagonal I - II; Cubic
Phenophylin
Sweet - Salty - Sour - and Bitter

42. 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
Thermus Aqauticus
Yes
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).

43. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Initiation - Propagation - Termination
Onions ( or leeks)
Bitter
Polyphenols

44. What charge will a protein have when the pH of its solution is below at - and above its pKa?
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Browning of freshly cut surfaces of fruits and vegetables.
Anomeric
pH below positive charge; pH at no charge; pH above negative charge

45. What enzyme causes hyrolytic rancidity in milk?
Covalent (strongest) and Hydrophobic (Weakest)
Pheophytin forms
Lipase
45% - 52% - 90%

46. What are the three stages of oxidative rancidity?
Prolamines
45% - 52% - 90%
ERH=100 x Aw
Initiation - Propagation - and Termination

47. Name 3 factors influencing the rate of lipid oxidation in foods.
ERH=100 x Aw
Ascorbic Acid and Citric Acid
Milk
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

48. What are proteins which are soluble in 50-80% ethanol known as?
Pectin Esterase
Prolamines
Phenophylin
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

49. 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
D: None of the above
Lipid oxidation
NaCl (it dissociated to a 2M solution)
HPLC has higher pressure than FPLC

50. How many polypeptide chains make up an antibody?
Olive Green
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.
Acetoin
Four