Vinegar and Citric Acid Questions and Answers

Multiple Choice Questions and Answers on Vinegar and Citric Acid

Question 1 : Cider vinegar is produced from

  1. fruit juices
  2. malted grain
  3. ethanol
  4. ale

Answer : 1

Question 2 : Ethanol is oxidized to acetic acid aerobically using

  1. Acetobacter
  2. Gluconobacter
  3. both (1) and (2)
  4. Lactobacillus

Answer : 3

Question 3 : Malt vinegar is produced from

  1. fruit juices
  2. malted grain
  3. ethanol
  4. ale

Answer : 2

Question 4 : In submerged process for the fermentation to produce citric acid

  1. A. niger is used with solid substrate as sweet potato
  2. A. niger floats on the surface of solution
  3. Fungal mycelium grows through out the solution in a deep tank
  4. both (1) and (2)

Answer : 3

Question 5 : Which substrate is used in the fermentation of citric acid?

  1. Beet molasses
  2. Sucrose
  3. Starch hydrolysate
  4. All of these

Answer : 4

Question 6 : Alegar is a type of vinegar produced from

  1. fruit juices
  2. malted grain
  3. ethanol
  4. ale

Answer : 4

Question 7 : During recovery step of citric acid, calcium citrate formed is treated with which of the following acid to precipitate calcium?

  1. HCl
  2. HNO3
  3. H2SO4
  4. None of these

Answer : 3

Question 8 : Vinegar production consists of

  1. aerobic fermentation
  2. anaerobic fermentation
  3. aerobic fermentation followed by anaerobic fermentation
  4. anaerobic fermentation followed by aerobic fermentation

Answer : 4

Question 9 : What is the pH of the medium when sucrose is used as substrate for the production of citric acid?

  1. 3
  2. 4
  3. 5
  4. 6

Answer : 1

Question 10 : In liquid surface culture process for the fermentation to produce citric acid

  1. A. niger is used with solid substrate as sweet potato
  2. A. niger floats on the surface of solution
  3. Fungal mycelium grows through out the solution in a deep tank
  4. both (1) and (2)

Answer : 2

Question 11 : In koji process for the fermentation to produce citric ac

  1. A. niger is used with solid substrate as sweet potato
  2. A. niger floats on the surface of solution
  3. Fungal mycelium grows through out the solution in a deep tank
  4. both (1) and (2)

Answer : 1

Question 12 : What is the pH of the medium when molasses is used as substrate for the production of citric acid?

  1. 3
  2. 4
  3. 5
  4. 6

Answer : 3

Question 13 : Which of the following nitrogen sources is added in the fermentation medium of citric acid production?

  1. Ammonium salt
  2. Urea
  3. Both (1) and (2)
  4. Peptone

Answer : 3

Question 14 : Vinegar is typically produced in fed batch reactors because

  1. a fed batch reactor can be used to maintain low acetic acid concentrations
  2. a fed batch reactor can be used to maintain low ethanol concentrations
  3. acetic acid bacteria tend to ferment at high ethanol concentrations
  4. all of the above

Answer : 2

Question 15 : For the recovery of citric acid after fermentation, Ca(OH)2 is added to the slurry to

  1. precipitate calcium carbonate
  2. precipitate calcium citrate
  3. precipitate calcium phosphate
  4. precipitate calcium sulphate

Answer : 2

Question 16 : Which of the following microorganism is used for the production of citric acid?

  1. Lactobacillus bulgaricus
  2. Saccharomyces cerevisiae
  3. Aspergillus niger
  4. Streptococcus lactis

Answer : 3

Question 17 : Sugar content of the fermentation medium for citric acid is maintained at

  1. 10-15%
  2. 15-20%
  3. 20-25 %
  4. 25-30 %

Answer : 3

Question 18 : Spirit vinegar is produced from

  1. fruit juices
  2. malted grain
  3. ethanol
  4. ale

Answer : 3