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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. What are two common reducing agents that break disulfide bonds in proteins?
pH 3-5
14
2-mercaptoethanol (2-ME) - dithiothreitol (DDT)
Fructose
2. Name 3 chemical agents capable of denaturing proteins.
D: None of the above
Fat Oxidation
Sodium chloride reduces foam stability and sucrose improves foam stability.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
3. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
Onions ( or leeks)
Daminozide
Fat Oxidation
V=IR and P=VI or I x I x are
4. What is the structural difference between chlorophyll and pheophytia?
V=IR and P=VI or I x I x are
Pheophytia does not have magnesium in porphyrin ring.
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
Fatty Acid and Alcohol
5. What is catalase?
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
Osmosis
Cis
An enzyme that converts hydrogen peroxide to water plus oxygen.
6. How is pH defined?
Fatty Acid and Alcohol
Parabens
Negative log of the hydrogen concentration (mol/l).
2.5
7. 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?
V=IR and P=VI or I x I x are
The speed of a molecule is proportional to the surrounding voltage gradient.
Covalent (strongest) and Hydrophobic (Weakest)
.05 M HCL
8. In genetics What is conjugation?
1 - 3 - 7-trimethylxanthine
Monosodium Glutamate
DNA transferred by cell to cell contact (bacterial sex).
Osmosis
9. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Water
Yes
Speed of Light
10. S-(1-propenyl)-L-cysteine sulfoxide is the chemical precursor to the major flavor compounds In what foodstuff?
ERH=100 x Aw
Onions ( or leeks)
Milk
2.5
11. What does the acronym NPN stand for?
It explodes
Linoleic Acid
Water
Non-protein nitrogen
12. What does Acid Degree Value measure and how is it measured?
Chlocophyllide does not have a phytoltail
Lysine - Arginine - and Histidine
Linoleic Acid
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
13. Name 3 factors influencing the consistency of commercial fats.
The amount of unsaturated bonds in fat; grams Iodine reacting with 100 grams fat.
Milk
Proportion of solids in the fat - number - size - and kinds of crystals - viscosity of the liquid - temperature treatment - and mechanical working.
A concentrate of microfibrillar proteins of fish muscle.
14. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
NaCl (it dissociated to a 2M solution)
ERH=100 x Aw
Onions ( or leeks)
Sweet - Salty - Sour - and Bitter
15. Name 5 chelating agents used in the food industry.
Fatty Acid and Alcohol
Plasmids
Four
EDTA - citric acid - malic acid - tartaric acid - oxalic acid - succinic acid - adenosine triphosphate - pyrophosphate - porphyrins - and proteins.
16. Which two amino acids is the aspartame derived from?
Aspartic Acid and Phenylalanine
Thermus Aqauticus
Chlocophyllide does not have a phytoltail
Osmosis
17. Name two main gluten proteins.
For proteins: SDA-PAGE. For DNA & RNA: Agarose gel.
Gliadins and Glutenins
Linoleic Acid
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
18. Which will be coldest at its freezing point: 1M dispersion of amylose 1M solution of NaCl - distilled water - or 1M solution of sucrose?
NaCl (it dissociated to a 2M solution)
No
Initiation - Propagation - and Termination
Phenylketonuria
19. Name a commonly used household chemical leavening agent and the gas it generates.
Linoleic Acid
Polyphenol Oxidase
Oil in Water
Sodium bicarbonate generates CO2
20. What two enzymes degrade pectic substances?
Lipid oxidation
Emulsoids
Pectin methylesterase & polygalacturonase
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
21. What is a polymorphism?
Temperature - Water Content and Activity - Extremes of pH - Chemicals - Alterations of Substrates - Alterations of Products - Preprocessing Controls
Anomeric
Non-protein nitrogen
Solid phases of the same chemical composition that differ by crystalline structure - but yield identical liquid phases upon melting.
22. What is the chemical nature of anthocyanins?
The speed of a molecule is proportional to the surrounding voltage gradient.
Cis
Tryptophan
Glycosides of anthocyanidins
23. Name 4 advantages of using enzymes in food processing.
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
They act as catalysts - speeding the polymerization of acrylamide.
Degradation of protein and production of acid from sugar at the same time.
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
24. What enzyme causes hyrolytic rancidity in milk?
Initiation - Propagation - and Termination
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
Lipase
Heat - Cold Mechanical Treatments - Hyrdostatic Pressure - Irradiation - and Interfaces
25. Name 3 reasons it is advantageous to obtain enzymes from microorganisms.
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26. What is the major color compound in tomatoes?
.05
Browning of freshly cut surfaces of fruits and vegetables.
1 - 3 - 7-trimethylxanthine
Lycopenes
27. Name two reasons why fats are hydrogenated.
Oil in Water
It allows the conversion of liquid oils into semisolid or plastic fats and it improves the oxidative stability of the fat.
Oil in Water
An enzyme that converts hydrogen peroxide to water plus oxygen.
28. What does the saponification value measure and how is it measured?
Oil in Water
Number of fatty acids present; mg KOH needed to saponify 1 g fat.
Arachidonic Acid
Nucleation or crystal formation and crystal growth.
29. What charge will a protein have when the pH of its solution is below at - and above its pKa?
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.
pH below positive charge; pH at no charge; pH above negative charge
Chlocophyllide does not have a phytoltail
Bitter
30. What are the limiting amino acids in corn - potato - and green peas?
Pectin Esterase - Polygalacturonase - Pectin Layase
Yellow
Ascorbic Acid and Citric Acid
Corn- Lysine - Potato-Methionine - Green Peas-Methionine
31. 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
Gliadins and Glutenins
Orange Juice
RNA transcribed to DNA
32. A chlorophyll molecule reacting with magnesium exhibits what shade of green?
Bright green
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
HPLC has higher pressure than FPLC
Pectin methyl esterase or galacturonase
33. What degradative enzyme causes browning in apples - pears - bananas - and peaches?
Acsulfame-K - Saccharin - Cyclamate - Aspartame
Glycosides of anthocyanidins
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.
Polyphenoloxidase
34. What enzyme is most responsible for browning bananas?
Arachidonic Acid
Fructose
Olive Green
Polyphenol Oxidase
35. Q What reaction does the enzyme 'reverse transcriptase' catalyze?
Gossypol (it is removed during the oil refining process)
RNA transcribed to DNA
Polyphenoloxidase
Gossypol (it is removed during the oil refining process)
36. What are soluble polymers of anhydro-galacturonic acid and its esters called?
Browning of freshly cut surfaces of fruits and vegetables.
.05
Pectins
Polyphenol Oxidase
37. What is Carboxy-methyl cellulose often used for?
Fatty Acid and Alcohol
Thickener in foods
Speed of Light
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
38. Name three compounds capable of poisoning the catalyst during commercial hydrogenation.
Racemic Mixture
Acids - Alkalis - Metals - Organic Solvents - and Aqueous Solutions of Organic Solvents
Phospholipids - water - sulfur compounds - soaps - partial glycerol esters - carbon dioxide - and mineral acids.
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.
39. Name three effects of protein denaturation.
Blue pigment in flowers
Decreased solubility - altered water-binding capacity - loss of biological activity - increased susceptibility to attack by proteases - increased intrinsic viscosity - inability to crystallize.
Lipase - lipoxygenase - catalase - chlorophylase - peroxidase - pectinase - protease - ascorbic acid oxidase - alkaline phosphotase.
Chlocophyllide does not have a phytoltail
40. Name three nonpolar polar - and charged amino acids.
Parabens
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Thermus Aqauticus
Polyphenols
41. What metabolic disorder prevents conversion of phenulalanine to tyrosine by normal metabolic pathways?
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Prolamines
Phenylketonuria
Parabens
42. What are proteins which are soluble in 50-80% ethanol known as?
Prolamines
NaCl (it dissociated to a 2M solution)
Water
Negative log of the hydrogen concentration (mol/l).
43. Name one way foam stability can be assessed.
100 Degrees Celsius (it is not a true solution-there is no boiling point of elevation)
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.
Cis
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.
44. Contains the lowest content of water
Yes
Pectins
Smoother - less acid and less bitter chocolate flavor - darker color - and improved solubility (elevated pH enhances sugar-amino browning reactions and polymerization of flavonoids).
Whole Milk
45. Name the strongest biochemical bond and the weakest biochemical bond.
Butter= water in oil Mayonnaise= oil in water Milk= oil in water
14
Amount of free fatty acids present; mg KOH needed to neutralize the free fatty acids in 1 g of fat.
Covalent (strongest) and Hydrophobic (Weakest)
46. Waxes are composed of what two basic chemical entities?
45% - 52% - 90%
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
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
47. During freezing What are the two stages in the crystallization process?
Fatty Acid and Alcohol
Nonpolar: (Valine - Alanine - Leucine - Isoleucine - Proline)Polar: (Glycine - Serine - Cystein - Threonine - Tyrosine)Charged: (Lysine - Arginine - Histidine - Aspartic Acid - Glutamic Acid)
Olive Green
Nucleation or crystal formation and crystal growth.
48. Define molarity molality - and normality.
Fatty acid composition - free fatty acids versus the corresponding glycerols - oxygen concentration - temperature - surface area - moisture - pro-oxidants - antioxidants
Molarity is moles of substance per liter solution. Molality is moles of substance per kg solvent. Normality is equivalents of substance per liter solution.
Fructose
Acsulfame-K - Saccharin - Cyclamate - Aspartame
49. How does HPLC differ from FPLC?
Nucleation or crystal formation and crystal growth.
HPLC has higher pressure than FPLC
Emulsification
Yellow
50. 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
Ascorbic Acid and Citric Acid
4:0 (Butyric) - 10:0 (Capric) - 12:0 (Lauric) - 14:0 (Myristic) - 16:0 (Palmitic) - 18:0 (Stearic)
Negative log of the hydrogen concentration (mol/l).
DNA transferred by cell to cell contact (bacterial sex).