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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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1. What is the chemical nomenclature for caffeine?
1 - 3 - 7-trimethylxanthine
Ammonia - Water - Carbon Dioxide
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Pectin Esterase - Polygalacturonase - Pectin Layase

2. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Yellow
RNA transcribed to DNA
Aspartic Acid and Phenylalanine
1 - 3 - 7-trimethylxanthine

3. Name three factors useful in controlling enzyme activity.
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
A concentrate of microfibrillar proteins of fish muscle.
Covalent (strongest) and Hydrophobic (Weakest)

4. How do sodium chloride and sucrose affect foam stability?
Milk
Lipid oxidation
Sodium chloride reduces foam stability and sucrose improves foam stability.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

5. Name three nonpolar polar - and charged amino acids.
Chlocophyllide does not have a phytoltail
They act as catalysts - speeding the polymerization of acrylamide.
Anomeric
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)

6. What is the protein efficiency ratio (PER) of casein?
Thamautin
2.5
Carrageenan
Two aldehydes

7. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Lycopenes
Olive Green
Milk
An enzyme that converts hydrogen peroxide to water plus oxygen.

8. Name the strongest biochemical bond and the weakest biochemical bond.
No
Olive Green
Covalent (strongest) and Hydrophobic (Weakest)
Anthocyanins

9. Name 4 advantages of using enzymes in food processing.
Thermus Aqauticus
NaCl (it dissociated to a 2M solution)
Gliadins and Glutenins
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

10. What is the major color compound in tomatoes?
Anthocyanins
Lycopenes
Negative log of the hydrogen concentration (mol/l).
Polyphenol Oxidase

11. What enzyme causes hyrolytic rancidity in milk?
Thamautin
Monosodium Glutamate
Lipase
Osmosis

12. What is the main class of color compounds found in raspberries?
14
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Anthocyanins
Lysine - Arginine - and Histidine

13. What is the enzyme responsible for browning in apples and lettuce?
Negative log of the hydrogen concentration (mol/l).
Fatty Acid (Ester linked) to Fatty Alcohol
Water
Polyphenol Oxidase

14. Name two non-enzymatic browning reactions.
The speed of a molecule is proportional to the surrounding voltage gradient.
Carmelization and Maillard
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

15. Name 2 heat stable enzymes in food that are important to the quality of aseptic products.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
No
20 carbons and 4 double bonds
Number of fatty acids present; mg KOH needed to saponify 1 g fat.

16. What are proteins which are soluble in 50-80% ethanol known as?
Phenylketonuria
Prolamines
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Negative log of the hydrogen concentration (mol/l).

17. Which two amino acids is the aspartame derived from?
Milk
Lamellar; Hexagonal I - II; Cubic
Aspartic Acid and Phenylalanine
Tryptophan

18. How does HPLC differ from FPLC?
Arachidonic Acid
Linoleic Acid
Thickener in foods
HPLC has higher pressure than FPLC

19. Name a commonly used household chemical leavening agent and the gas it generates.
Sucrose
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Sodium bicarbonate generates CO2
.05

20. What is the structural difference between chlorophyll and chlocophyllide?
20 carbons and 4 double bonds
Pectin Esterase
Chlocophyllide does not have a phytoltail
.05

21. What is the winterization process for an oil?
Capsaicin
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Polyphenoloxidase

22. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Onions ( or leeks)
Gliadins and Glutenins
Aspartic Acid and Phenylalanine
Anthocyanins

23. What two types of compounds are joined with an ester bond to make a wax?
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
Fatty Acid and Alcohol
Thickener in foods
Acetoin

24. Name 3 factors influencing the consistency of commercial fats.
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.
Bright green
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Pectin Esterase - Polygalacturonase - Pectin Layase

25. What is the name of the structural carbohydrate found in lobsters crab - shellfish - and insects?
Chitin
Pectin methyl esterase or galacturonase
45% - 52% - 90%
Plasmids

26. Name a naturally occurring protein sweetener.
Monosodium Glutamate
Thamautin
Bright 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.

27. An emulsifier with a high hydrophilic-lipophilic balance (HLB) value would promote which type of emulsion: oil in water or water in oil?
Oil in Water
Lipase
Lipid oxidation
Tryptophan

28. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Initiation - Propagation - Termination
Pectins
Linoleic Acid
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.

29. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Water
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Polyphenoloxidase

30. Alar is the trade name for what chemical compound?
Yellow
Capsaicin
Daminozide
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.

31. What are the four basic flavors perceived by the tongue?
Olive Green
Ascorbic Acid and Citric Acid
Pectins
Sweet - Salty - Sour - and Bitter

32. What are the only phenols approved for use in the microbiological preservation of foods?
Parabens
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Carrageenan

33. Name the most common functional property of phospholipids in food systems.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Daminozide
Emulsification
Pheophytia does not have magnesium in porphyrin ring.

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

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35. What is catalase?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
An enzyme that converts hydrogen peroxide to water plus oxygen.
Non-protein nitrogen
Emulsification

36. Waxes are composed of what two basic chemical entities?
RNA transcribed to DNA
Two aldehydes
Fatty Acid (Ester linked) to Fatty Alcohol
Osmosis

37. 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
Orange Juice
Daminozide
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
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

38. Name 3 chemical agents capable of denaturing proteins.
It explodes
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Lipase
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents

39. What kinds of food emulsions are? (1) Butter (2) Mayonnaise(3) Milk
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Polyphenol Oxidase
Nucleation or crystal formation and crystal growth.
Milk

40. Name the strongest biochemical bond and the weakest biochemical bond.
Pheophytia does not have magnesium in porphyrin ring.
pH 3-5
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Covalent (strongest) and Hydrophobic (Weakest)

41. Name three non-nutritive sweeteners approved for use in USA?
.05
Daminozide
Two aldehydes
Acsulfame-K - Saccharin - Cyclamate - Aspartame

42. Name the three positively charged amino acids.
V=IR and P=VI or I x I x are
They act as catalysts - speeding the polymerization of acrylamide.
Lysine - Arginine - and Histidine
Fatty Acid and Alcohol

43. What is an isomer that is cheaper than Vitamin C?
Polyphenols
Erythorbic Acid
Acsulfame-K - Saccharin - Cyclamate - Aspartame
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.

44. What is an isomer that is cheaper than Vitamin C?
Carmelization and Maillard
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Milk
Erythorbic Acid

45. How does ERH relate to water activity?
Chitin
Phenylketonuria
Thamautin
ERH=100 x Aw

46. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Polyphenoloxidase
Two aldehydes
Bitter
Browning of freshly cut surfaces of fruits and vegetables.

47. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
pH below positive charge; pH at no charge; pH above negative charge
Daminozide
Fat Oxidation
They act as catalysts - speeding the polymerization of acrylamide.

48. What compounds oxidize to form brown color in fruits and vegetables?
Sodium chloride reduces foam stability and sucrose improves foam stability.
Polyphenols
Prolamines
Parabens

49. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
1 - 3 - 7-trimethylxanthine
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Osmosis
Yellow

50. What are the only phenols approved for use in the microbiological preservation of foods?
Thamautin
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Parabens
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.