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Test your basic knowledge |
Food Chemistry
Start Test
Study First
Subjects
:
engineering
,
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
HPLC has higher pressure than FPLC
Lycopenes
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
2. A) Is the major component of most foods.B) Controls shelf-life or storage capabilityC) Regulates chemical and microbiological reactionsD) All of the above
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Water
Pectin methyl esterase or galacturonase
3. 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?
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.
Fatty Acid and Alcohol
Daminozide
.05 M HCL
4. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Acetoin
Pectin methyl esterase or galacturonase
Water
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
5. What are two common reducing agents that break disulfide bonds in proteins?
Degradation of protein and production of acid from sugar at the same time.
Pheophytia does not have magnesium in porphyrin ring.
Pectin methylesterase & polygalacturonase
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
6. What compounds oxidize to form brown color in fruits and vegetables?
1 - 3 - 7-trimethylxanthine
Parabens
Polyphenols
Phenophylin
7. What are the fructose contents in commercial HFCS products.
Lysine - Arginine - and Histidine
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Thamautin
45% - 52% - 90%
8. What is the enzyme that softens tomatoes?
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.
Polyphenols
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
9. 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)
Whole Milk
Arachidonic Acid
Thickener in foods
10. How many carbon atoms and how many double bonds are there in arachidonic acid?
20 carbons and 4 double bonds
Fructose
Carmelization and Maillard
Lysine - Arginine - and Histidine
11. To which of the following four basic tastes are humans most sensitive? A) Bitter B) Sweet C) Sour D) Salty
Sucrose
Bitter
.05
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
12. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Polyphenol Oxidase
Onions ( or leeks)
An enzyme that converts hydrogen peroxide to water plus oxygen.
Pectins
13. What enzyme is most responsible for browning bananas?
Polyphenol Oxidase
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
Lipid oxidation
Phenylketonuria
14. Will lipid oxidation be higher at a water activity of .05 or .5?
Glycosides of anthocyanidins
.05
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
Anthocyanins
15. What is the name given to a mixture of equal parts of Darel Lisomers?
Parabens
Racemic Mixture
Linoleic Acid
Pectin Esterase
16. What are the three stages of oxidative rancidity?
Degradation of protein and production of acid from sugar at the same time.
No
Initiation - Propagation - and Termination
Blue pigment in flowers
17. Name 3 reasons it is advantageous to obtain enzymes from microorganisms.
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18. What compounds oxidize to form brown color in fruits and vegetables?
Polyphenols
Emulsification
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Emulsification
19. At low water activity What is the main deteriorative concern?
Four
Browning of freshly cut surfaces of fruits and vegetables.
Lipid oxidation
They act as catalysts - speeding the polymerization of acrylamide.
20. What is the name of the degradation compound of chlorophyll?
Parabens
Pheophytin forms
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.
Phenophylin
21. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Anthocyanins
No
Bright green
pH below positive charge; pH at no charge; pH above negative charge
22. Name one way foam stability can be assessed.
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
Linoleic Acid
Acsulfame-K - Saccharin - Cyclamate - Aspartame
23. Name three non-nutritive sweeteners approved for use in USA?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Anthocyanins
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.
24. What is the main class of color compounds found in raspberries?
Gossypol (it is removed during the oil refining process)
Oil in Water
Anthocyanins
Arachidonic Acid
25. Name two main gluten proteins.
Polyphenol Oxidase
Gliadins and Glutenins
Lipid oxidation
Pheophytin forms
26. What is the movement of molecules through a semi permeable membrane from a region of low to high solute concentration called?
Thickener in foods
Osmosis
Four
Anthocyanins
27. In polyacrylamide gel electrophoresis (PAGE) what purpose do ammonium persulfates (APS) and TEMED serve?
Troponins and Tropomyosin
Browning of freshly cut surfaces of fruits and vegetables.
An enzyme that converts hydrogen peroxide to water plus oxygen.
They act as catalysts - speeding the polymerization of acrylamide.
28. What are 3 mesomorphic structures associated with lipids in the liquid state?
Polyphenols
Chlocophyllide does not have a phytoltail
Lamellar; Hexagonal I - II; Cubic
Carrageenan
29. Name two non-enzymatic browning reactions.
Pheophytin forms
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
Carmelization and Maillard
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
30. What effect would the addition of sodium bicarbonate have to chocolate?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Chlocophyllide does not have a phytoltail
It explodes
Water
31. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
RNA transcribed to DNA
Tryptophan
Pectins
32. At low water activity What is the main deteriorative concern?
Anomeric
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Nucleation or crystal formation and crystal growth.
Lipid oxidation
33. Name three factors useful in controlling enzyme activity.
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Degradation of protein and production of acid from sugar at the same time.
Two aldehydes
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
34. A chlorophyll molecule reacting with hydrogen exhibits what shade of green?
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Initiation - Propagation - Termination
Olive Green
35. What is the enzyme that softens tomatoes?
Polyphenoloxidase
Four
Fatty Acid (Ester linked) to Fatty Alcohol
Pectin Esterase
36. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Pectins
Sodium chloride reduces foam stability and sucrose improves foam stability.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Pectin methyl esterase or galacturonase
37. What is the geometric configuration of double bonds in most natural fatty acids?
Capsaicin
Cis
Speed of Light
Water
38. What is the major color compound in tomatoes?
Olive Green
Initiation - Propagation - and Termination
Lycopenes
20 carbons and 4 double bonds
39. How many polypeptide chains make up an antibody?
Four
Aspartic Acid and Phenylalanine
Parabens
Cis
40. What does the 'c' stand for in the equation E=mc2?
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
Pectin Esterase - Polygalacturonase - Pectin Layase
Anomeric
Speed of Light
41. Name two reasons why fats are hydrogenated.
Milk
Onions ( or leeks)
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
42. 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
Polyphenol Oxidase
Water
D: None of the above
Pectin Esterase
43. If oxygen attacks an unsaturated fatty acids at the double bond What is the resultant product?
Two aldehydes
Sucrose
Milk
Acetoin
44. What metabolic end product does the Voges-Proskauer test detect?
Acetoin
Sucrose
Primary butyric acid also caproic acid.
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
45. Alar is the trade name for what chemical compound?
Glycosides of anthocyanidins
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.
Daminozide
Ammonia - Water - Carbon Dioxide
46. What is a polymorphism?
Osmosis
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
Osmosis
Racemic Mixture
47. What does the iodine value measure and how is it measured?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Bitter
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
48. Name 4 advantages of using enzymes in food processing.
.05
Cooling the oil and filtering of the solids formed so that long chained saturated fats do not crystallize at low temperatures.
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
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
49. What does Acid Degree Value measure and how is it measured?
NaCl (it dissociated to a 2M solution)
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Fat Oxidation
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
50. What ketohexose is most significant to food chemists?
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
Fructose
Lycopenes
D: None of the above