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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 is Ohm's Law and What is Power Equation?
Lipase
Ascorbic Acid and Citric Acid
45% - 52% - 90%
V=IR and P=VI or I x I x are

2. What does the iodine value measure and how is it measured?
Negative log of the hydrogen concentration (mol/l).
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Yellow

3. How is pH defined?
Degradation of protein and production of acid from sugar at the same time.
Pectin Esterase
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
Negative log of the hydrogen concentration (mol/l).

4. Name three nonpolar polar - and charged amino acids.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Chlocophyllide does not have a phytoltail
HPLC has higher pressure than FPLC
Polyphenoloxidase

5. What is the geometric configuration of double bonds in most natural fatty acids?
Fatty Acid and Alcohol
Pectin methylesterase & polygalacturonase
Cis
Water

6. Define molarity molality - and normality.
Gliadins and Glutenins
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
No
Carrageenan

7. Name 4 advantages of using enzymes in food processing.
RNA transcribed to DNA
A concentrate of microfibrillar proteins of fish muscle.
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
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

8. The undesirable clarification of orange juice or tomato juice (precipitation of pulp) is caused by what enzymes?
A concentrate of microfibrillar proteins of fish muscle.
Daminozide
Orange Juice
Pectin methyl esterase or galacturonase

9. Name the strongest biochemical bond and the weakest biochemical bond.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Non-protein nitrogen
Covalent (strongest) and Hydrophobic (Weakest)
ERH=100 x Aw

10. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Polyphenoloxidase
Gliadins and Glutenins
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
A concentrate of microfibrillar proteins of fish muscle.

11. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
.05 M HCL
Acetoin
Bitter
Arachidonic Acid

12. Name one way foam stability can be assessed.
Water
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.
D: None of the above
1 - 3 - 7-trimethylxanthine

13. What is the Peroxide Value a measure of?
Fat Oxidation
Chlocophyllide does not have a phytoltail
Polyphenol Oxidase
Carrageenan

14. Name a naturally occurring protein sweetener.
Chlocophyllide does not have a phytoltail
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Emulsoids
Thamautin

15. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Pheophytin forms
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Two aldehydes
Osmosis

16. Are sorbitol and mannitol sweet?
Plasmids
Yes
Sweet - Salty - Sour - and Bitter
Polyphenol Oxidase

17. 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
Sodium chloride reduces foam stability and sucrose improves foam stability.
Browning of freshly cut surfaces of fruits and vegetables.
Plasmids
Monosodium Glutamate

18. Name two non-enzymatic browning reactions.
Chlocophyllide does not have a phytoltail
Fatty Acid and Alcohol
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Carmelization and Maillard

19. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Polyphenoloxidase
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
45% - 52% - 90%

20. What are proteins which are soluble in 50-80% ethanol known as?
Osmosis
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.
Prolamines
Thickener in foods

21. What is the major color compound in tomatoes?
2.5
ERH=100 x Aw
Thickener in foods
Lycopenes

22. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Four
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Tryptophan
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.

23. Name a naturally occurring protein sweetener.
Sodium chloride reduces foam stability and sucrose improves foam stability.
Gossypol (it is removed during the oil refining process)
Thamautin
Pectin Esterase - Polygalacturonase - Pectin Layase

24. What is the enzyme that softens tomatoes?
Troponins and Tropomyosin
It explodes
Pectin Esterase
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

25. What is surimi?
A concentrate of microfibrillar proteins of fish muscle.
Racemic Mixture
pH 3-5
Osmosis

26. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Negative log of the hydrogen concentration (mol/l).
Daminozide
Lipase
Yellow

27. What is the acid present in fish oil?
Sodium bicarbonate generates CO2
Carrageenan
Whole Milk
Arachidonic Acid

28. 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
Troponins and Tropomyosin
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Pectin methylesterase & polygalacturonase

29. How many carbon atoms are there in the fatty acid myristic acid?
A concentrate of microfibrillar proteins of fish muscle.
V=IR and P=VI or I x I x are
14
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

30. Give one word for a carbon atom involved in hemiacetal or acetal formation.
Tryptophan
Pheophytin forms
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Anomeric

31. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Yellow
Orange Juice
DNA transferred by cell to cell contact (bacterial sex).
Gliadins and Glutenins

32. Name three non-nutritive sweeteners approved for use in USA?
Lipid oxidation
RNA transcribed to DNA
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Thermus Aqauticus

33. Alar is the trade name for what chemical compound?
Blue pigment in flowers
Polyphenols
Daminozide
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.

34. What is Carboxy-methyl cellulose often used for?
Negative log of the hydrogen concentration (mol/l).
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Thickener in foods
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)

35. How does ERH relate to water activity?
ERH=100 x Aw
Carrageenan
Non-protein nitrogen
Negative log of the hydrogen concentration (mol/l).

36. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
Polyphenoloxidase
It explodes
Lipase

37. Name 3 chemical agents capable of denaturing proteins.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Orange Juice
14
Water

38. What two enzymes degrade pectic substances?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Yes
Pectin methylesterase & polygalacturonase
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

39. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Water
Chlocophyllide does not have a phytoltail
Erythorbic Acid
Pectin methyl esterase or galacturonase

40. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
The speed of a molecule is proportional to the surrounding voltage gradient.
Pheophytia does not have magnesium in porphyrin ring.
Tryptophan
2.5

41. When heated ammonium bicarbonate decomposes to form what end products?
Water
Pectins
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Ammonia - Water - Carbon Dioxide

42. Will lipid oxidation be higher at a water activity of .05 or .5?
.05
Degradation of protein and production of acid from sugar at the same time.
Prolamines
Pectin Esterase - Polygalacturonase - Pectin Layase

43. 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
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Emulsification
Browning of freshly cut surfaces of fruits and vegetables.
Emulsification

44. Name two reasons why fats are hydrogenated.
Lipid oxidation
Fructose
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
An enzyme that converts hydrogen peroxide to water plus oxygen.

45. What does HLB stand for and What does a high and low HLB value indicate?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
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-mercaptoethanol (2-ME) - dithiothreitol (DDT)

46. Which of these foods is not appropriate to this list? A) Salami B) Yogurt C) Orange Juice D) Beer
Acetoin
pH below positive charge; pH at no charge; pH above negative charge
pH 3-5
Orange Juice

47. What name is given to the small circular DNA molecules that carry genetic information independently of the main bacterial chromosome?
Whole Milk
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Plasmids
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.

48. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Lamellar; Hexagonal I - II; Cubic
Troponins and Tropomyosin
Capsaicin
Bright green

49. Name 3 reasons it is advantageous to obtain enzymes from microorganisms.

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50. What is the chemical nomenclature for caffeine?
Plasmids
Ammonia - Water - Carbon Dioxide
1 - 3 - 7-trimethylxanthine
Onions ( or leeks)