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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 toxic pigment is found in cottonseed endosperm?
Gossypol (it is removed during the oil refining process)
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Browning of freshly cut surfaces of fruits and vegetables.
DNA transferred by cell to cell contact (bacterial sex).

2. What ketohexose is most significant to food chemists?
Fructose
Pectin methylesterase & polygalacturonase
A concentrate of microfibrillar proteins of fish muscle.
Osmosis

3. What are the limiting amino acids in corn - potato - and green peas?
Four
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Polyphenoloxidase
Gliadins and Glutenins

4. Alar is the trade name for what chemical compound?
Daminozide
Degradation of protein and production of acid from sugar at the same time.
The speed of a molecule is proportional to the surrounding voltage gradient.
Lysine - Arginine - and Histidine

5. Name the strongest biochemical bond and the weakest biochemical bond.
Plasmids
Parabens
Negative log of the hydrogen concentration (mol/l).
Covalent (strongest) and Hydrophobic (Weakest)

6. Name two main gluten proteins.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Gliadins and Glutenins
Negative log of the hydrogen concentration (mol/l).
An enzyme that converts hydrogen peroxide to water plus oxygen.

7. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
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.
Aspartic Acid and Phenylalanine
2.5

8. What are the primary secondary - tertiary - and quaternary structures?
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
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.
Aspartic Acid and Phenylalanine
Butter= water in oil Mayonnaise= oil in water Milk= oil in water

9. If you take 20 ml of .1 M NaOH to titrate 40 mL of an HCL solution to the penolphthalein end point What is the molarity of the HCL solution?
Polyphenol Oxidase
Monosodium Glutamate
.05 M HCL
Parabens

10. What is the acid present in fish oil?
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.
Glycosides of anthocyanidins
Arachidonic Acid
They act as catalysts - speeding the polymerization of acrylamide.

11. What enzyme is most responsible for browning bananas?
Bitter
Non-protein nitrogen
Polyphenol Oxidase
2.5

12. Name three non-nutritive sweeteners approved for use in USA?
Erythorbic Acid
Pectin methyl esterase or galacturonase
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Acsulfame-K - Saccharin - Cyclamate - Aspartame

13. Name two enzymes that are involved in softening fruits.
Pectin Esterase - Polygalacturonase - Pectin Layase
No
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.

14. Name 3 factors influencing the rate of lipid oxidation in foods.
Pectin Esterase
Oil in Water
Polyphenol Oxidase
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants

15. What are the only phenols approved for use in the microbiological preservation of foods?
Plasmids
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
Parabens
Pectin Esterase

16. How does ERH relate to water activity?
Acetoin
Yellow
Racemic Mixture
ERH=100 x Aw

17. If the absorption of a sample is being determined spectrophotometrically at 420 nm what color is the sample?
Chlocophyllide does not have a phytoltail
14
Yellow
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.

18. What is the protein efficiency ratio (PER) of casein?
2.5
Thickener in foods
Blue pigment in flowers
Water

19. What does the saponification value measure and how is it measured?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
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 - and Termination
Anthocyanins

20. What does the acronym NPN stand for?
Polyphenol Oxidase
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
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
Non-protein nitrogen

21. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
Negative log of the hydrogen concentration (mol/l).
ERH=100 x Aw
NaCl (it dissociated to a 2M solution)
Corn- Lysine - Potato-Methionine - Green Peas-Methionine

22. What is acid proteolysis?
Emulsoids
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Onions ( or leeks)
Degradation of protein and production of acid from sugar at the same time.

23. Name 3 physical agents capable of denaturing proteins.
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
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
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces

24. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
Olive Green
Emulsoids
Glycosides of anthocyanidins
Anthocyanins

25. When heated ammonium bicarbonate decomposes to form what end products?
Thamautin
Ammonia - Water - Carbon Dioxide
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.

26. What are the primary secondary - tertiary - and quaternary structures?
Negative log of the hydrogen concentration (mol/l).
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.
Bright green
HPLC has higher pressure than FPLC

27. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Monosodium Glutamate
Initiation - Propagation - and Termination
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Bright green

28. 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.
They act as catalysts - speeding the polymerization of acrylamide.
Water
Browning of freshly cut surfaces of fruits and vegetables.

29. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
They act as catalysts - speeding the polymerization of acrylamide.
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Polyphenols

30. What are the three main steps in the autooxidation of lipids?
Monosodium Glutamate
Linoleic Acid
Initiation - Propagation - Termination
V=IR and P=VI or I x I x are

31. Name two non-enzymatic browning reactions.
Carmelization and Maillard
Daminozide
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Milk

32. What is the enzyme responsible for browning in apples and lettuce?
Whole Milk
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Polyphenol Oxidase

33. Does kosmotrophil ion discourage water structure?
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.
They act as catalysts - speeding the polymerization of acrylamide.
Orange Juice
No

34. What is the common name for 9 12 - cis-cis-octa dienoic acid?
Yellow
Covalent (strongest) and Hydrophobic (Weakest)
Linoleic Acid
Blue pigment in flowers

35. 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
Two aldehydes
Browning of freshly cut surfaces of fruits and vegetables.
Carrageenan
Plasmids

36. Name the three positively charged amino acids.
Lysine - Arginine - and Histidine
Oil in Water
Water
ERH=100 x Aw

37. What are the limiting amino acids in corn - potato - and green peas?
Phenylketonuria
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Lycopenes

38. Peptide bond formation results in the formation of what secondary compound?
Water
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.
Tryptophan
Acsulfame-K - Saccharin - Cyclamate - Aspartame

39. Name 4 advantages of using enzymes in food processing.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
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
Tryptophan
D: None of the above

40. Peptide bond formation results in the formation of what secondary compound?
Thickener in foods
Thamautin
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.
Water

41. Which amino acid has the greatest molecular weight: tryptophan or tyrosine?
Tryptophan
Two aldehydes
Erythorbic Acid
Milk

42. What does HLB stand for and What does a high and low HLB value indicate?
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
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.
Arachidonic Acid
Sucrose

43. 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
Linoleic Acid
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
pH 3-5

44. How many carbon atoms are there in the fatty acid myristic acid?
It explodes
Polyphenol Oxidase
14
Sucrose

45. What are proteins which are soluble in 50-80% ethanol known as?
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
Fatty Acid (Ester linked) to Fatty Alcohol
Prolamines
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.

46. Name the strongest biochemical bond and the weakest biochemical bond.
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Covalent (strongest) and Hydrophobic (Weakest)
Polyphenol Oxidase

47. What is an isomer that is cheaper than Vitamin C?
Water
Anthocyanins
Erythorbic Acid
Pectin Esterase

48. What is the structural difference between chlorophyll and chlocophyllide?
Chlocophyllide does not have a phytoltail
Phenylketonuria
Water
Aspartic Acid and Phenylalanine

49. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Tryptophan
Emulsoids
Phenophylin

50. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Fatty Acid and Alcohol
An enzyme that converts hydrogen peroxide to water plus oxygen.
Phenylketonuria
Sodium chloride reduces foam stability and sucrose improves foam stability.