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. 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?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Oil in Water
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

2. Name the strongest biochemical bond and the weakest biochemical bond.
Bright green
Olive Green
1 - 3 - 7-trimethylxanthine
Covalent (strongest) and Hydrophobic (Weakest)

3. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Olive Green
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
pH below positive charge; pH at no charge; pH above negative charge

4. What is surimi?
A concentrate of microfibrillar proteins of fish muscle.
14
No
Carmelization and Maillard

5. What is the fundamental driving of electrophoresis?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
The speed of a molecule is proportional to the surrounding voltage gradient.
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Phenylketonuria

6. 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
Browning of freshly cut surfaces of fruits and vegetables.
Ascorbic Acid and Citric Acid
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
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

7. Name two enzymes that are involved in softening fruits.
Yes
Pectins
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
Pectin Esterase - Polygalacturonase - Pectin Layase

8. What is the chemical nomenclature for caffeine?
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
1 - 3 - 7-trimethylxanthine
Capsaicin
Two aldehydes

9. What is a polymorphism?
Anomeric
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
NaCl (it dissociated to a 2M solution)
RNA transcribed to DNA

10. 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?
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
It explodes
Ascorbic Acid and Citric Acid

11. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Thamautin
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.
Thermus Aqauticus
Plasmids

12. What two common compounds are used together as an antioxidative system?
Initiation - Propagation - Termination
HPLC has higher pressure than FPLC
Lysine - Arginine - and Histidine
Ascorbic Acid and Citric Acid

13. Name the most common functional property of phospholipids in food systems.
2.5
Pheophytin forms
Pheophytin forms
Emulsification

14. Will lipid oxidation be higher at a water activity of .05 or .5?
Prolamines
.05
Yes
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

15. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Polyphenoloxidase
Phenylketonuria
2.5
Non-protein nitrogen

16. What is the winterization process for an oil?
Arachidonic Acid
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.
RNA transcribed to DNA

17. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Onions ( or leeks)
Yes
Speed of Light

18. What are the limiting amino acids in corn - potato - and green peas?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
NaCl (it dissociated to a 2M solution)
Speed of Light

19. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Onions ( or leeks)
Cis
Sucrose
Yes

20. 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.
Milk
HPLC has higher pressure than FPLC
An enzyme that converts hydrogen peroxide to water plus oxygen.

21. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Osmosis
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Pectin Esterase - Polygalacturonase - Pectin Layase
Linoleic Acid

22. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
RNA transcribed to DNA
Polyphenols
Non-protein nitrogen
1 - 3 - 7-trimethylxanthine

23. What are the three stages of oxidative rancidity?
Emulsification
2.5
Initiation - Propagation - and Termination
14

24. What is Carboxy-methyl cellulose often used for?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
V=IR and P=VI or I x I x are
Thickener in foods

25. What ketohexose is most significant to food chemists?
Yellow
Phenophylin
Fructose
Degradation of protein and production of acid from sugar at the same time.

26. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Osmosis
Gossypol (it is removed during the oil refining process)
NaCl (it dissociated to a 2M solution)

27. Name three nonpolar polar - and charged amino acids.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Polyphenols
Troponins and Tropomyosin

28. What is an isomer that is cheaper than Vitamin C?
Water
Carrageenan
Erythorbic Acid
.05 M HCL

29. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Phenophylin
Polyphenol Oxidase
Olive Green
Troponins and Tropomyosin

30. At what pH is benzoic acid most effective?
Carmelization and Maillard
pH 3-5
Ascorbic Acid and Citric Acid
Emulsoids

31. How can a molecular weight of protein - DNA - and RNA be determined?
No
Whole Milk
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Non-protein nitrogen

32. In the enzyme Taq Polymerase What does Taq stand for?
Non-protein nitrogen
Chitin
Phenophylin
Thermus Aqauticus

33. In genetics What is conjugation?
Emulsification
Lipid oxidation
DNA transferred by cell to cell contact (bacterial sex).
Thickener in foods

34. Name 3 physical agents capable of denaturing proteins.
2.5
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
A concentrate of microfibrillar proteins of fish muscle.
Fatty Acid (Ester linked) to Fatty Alcohol

35. What is the structural difference between chlorophyll and pheophytia?
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Pheophytia does not have magnesium in porphyrin ring.
Emulsoids
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

36. What toxic pigment is found in cottonseed endosperm?
Onions ( or leeks)
Water
Gossypol (it is removed during the oil refining process)
ERH=100 x Aw

37. Name 5 proteins with good foaming properties.
Polyphenoloxidase
DNA transferred by cell to cell contact (bacterial sex).
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.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

38. 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
Oil in Water
D: None of the above
RNA transcribed to DNA
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

39. What metabolic end product does the Voges-Proskauer test detect?
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.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Gossypol (it is removed during the oil refining process)
Acetoin

40. What does the acronym NPN stand for?
Non-protein nitrogen
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Linoleic Acid
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.

41. Alar is the trade name for what chemical compound?
Four
Water
Daminozide
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

42. Name three non-nutritive sweeteners approved for use in USA?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Bright green

43. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Chitin

44. What are proteins which are soluble in 50-80% ethanol known as?
Sodium bicarbonate generates CO2
Orange Juice
Fatty Acid (Ester linked) to Fatty Alcohol
Prolamines

45. What is the geometric configuration of double bonds in most natural fatty acids?
Cis
Anthocyanins
Emulsification
Olive Green

46. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
V=IR and P=VI or I x I x are
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Tryptophan
pH 3-5

47. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
D: None of the above
20 carbons and 4 double bonds
Initiation - Propagation - and Termination

48. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Blue pigment in flowers
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Orange Juice

49. Waxes are composed of what two basic chemical entities?
Prolamines
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Fatty Acid (Ester linked) to Fatty Alcohol
Fructose

50. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Daminozide
Troponins and Tropomyosin