Category: Fermentation Technology Objective Questions

Fermentation Technology Multiple Choice Questions on “Fermentation Biochemistry – Carbohydrate Dissimilation”.

1. The breakdown of glucose is known as ______________
A. Gluconeogenesis
B. Glycolysis
C. Glycogenolysis
D. Glycogenesisid5fdb6cfb83ad7″

Answer: B
Clarification: The breakdown of glucose is known as Glycolysis. It is also called an Embden-Myerhoff pathway. The breakdown of glucose results in the production of pyruvate. The process utilizes 2 ATP and also produces 4 ATP, therefore, net ATP produces is two.

2. Who discovered that carbon in yeast is dissimilated via the glycolytic pathway?
A. Lagunas
B. Bruinenberg
C. Embden
D. Myerhoffid5fdb6cfb83b05″

Answer: A
Clarification: Lagunas in 1986 discovered that carbon in Saccharomyces cerevisiae is dissimilated via the glycolytic pathway for the production of ATP and then ethanol production via fermentation route.

3. The RAS system was identified in ____________
A. Animal cells
B. Plant cells
C. Bacterial cells
D. Mammalian cellsid5fdb6cfb83b14″

Answer: D
Clarification: The RAS system was identified in mammalian tumour cells where they are involved in the regulation of cellular proliferation and homologous systems have also been found in yeast cells. It was discovered by Tamanoi in 1988.

4. What results in the activation of RAS genes?
A. GTP to GDP
B. ATP to ADP
C. GDP to GTP
D. ADP to ATPid5fdb6cfb83b20″

Answer: C
Clarification: The conversion of GDP to GTP results in the activation of RAS genes. It is an external nutritional system. It can be concluded that RAS genes have an intrinsic GTPase activity and are active in a GTP-bound form and not in GDP-bound form.

5. Which of the following prevents fermentation in the presence of oxygen?
A. Long term Crabtree effect
B. Short term Crabtree effect
C. Kluyver effect
D. Pasteur effectid5fdb6cfb83b2a”

Answer: D
Clarification: The inhibition of alcoholic fermentation in the presence of oxygen is known as the Pasteur effect. It is of little importance in Saccharomyces and is only expressed under specific conditions.

6. Which of the following causes the stimulation of glucose fermentation to ethanol?
A. Custers effect
B. Kluyver effect
C. Pasteur effect
D. Crabtree effectid5fdb6cfb83b35″

Answer: A
Clarification: Custers effect is the stimulation of glucose fermentation to ethanol. The stimulation occurs in the presence of oxygen. It is attributed to Brettanomyces to produce acetic acid from glucose. The fermentation of yeast is more rapid under aerobic conditions.

7. Which of the following effect causes instantaneous alcoholic fermentation?
A. Short term Crabtree effect
B. Long term Crabtree effect
C. Kluyver effect
D. Pasteur effectid5fdb6cfb83b3f”

Answer: B
Clarification: Short term Crabtree effect causes the instantaneous aerobic ethanolic alcohol formation fermentation following the transition from the limitation of carbon to excessive carbon.

8. Which of the following effect activates glycolysis?
A. Custers effect
B. Crabtree effect
C. Kluyver effect
D. Pasteur effectid5fdb6cfb83b4a”

Answer: D
Clarification: Pasteur effect leads to the activation of glycolysis by anaerobiosis. It leads to the production of energy in the form of two ATP. The rate of glycolysis is increased by a shift from aerobic to anaerobic conditions or suppression of ethanol formation.

9. Which of the following suppresses respiratory metabolism?
A. Custers effect
B. Kluyver effect
C. Carbon catabolite
D. Crabtree effectid5fdb6cfb83b54″

Answer: C
Clarification: Carbon catabolite repression and inactivation suppresses respiratory metabolism by high sugar concentrations. It is an important part of the global control system of various bacteria and other microorganisms.

10. Glycogen is a polymer of ________________
A. β-Glucose
B. α-Glucose
C. α (1,6)-Glucose
D. β (1,4)-Glucoseid5fdb6cfb83b5d”

Answer: B
Clarification: Glycogen is a polymer of α-D-Glucose with a molecular weight of the order of 10⁸. It has a branched structure containing chains of 10-14 residues of glucose. It is synthesized from glucose.

11. Who investigated the accumulation of trehalose in lager yeast?
A. Gelinas
B. Trivedi
C. Jacobsen
D. Majaraid5fdb6cfb83b66″

Answer: D
Clarification: Majara et al. in 1996 investigated the accumulation of trehalose in lager yeast fermentation using wort of varying gravities between 11 and 25° Plato. It was demonstrated that trehalose accumulation occurred in late fermentation at a concentration proportional to the gravity of the wort.

12. Who developed the concept of FGMIP?
A. Thevelein and Hohmann
B. Boultan et al.
C. Callaerts et al.
D. Nes et al.id5fdb6cfb83b70″

Answer: A
Clarification: Thevelein and Hohmann in 1995 developed a concept of FGMIP. FGMIP is termed as the ‘fermentable growth medium induced pathway’. It is defined as one or more signal transduction pathways which get activated by a combination of specific nutrients, fermentable sugars and other nutrients required for the growth.

13. Trehalose is a polysaccharide.
A. True
B. Falseid5fdb6cfb83b7a”

Answer: B
Clarification: Trehalose is a disaccharide that consists of two molecules of D-glucose. It is synthesized in the reactions which utilize uridine diphosphate as a carrier of glucose molecules.

14. Glycogen is an energy storage molecule.
A. True
B. Falseid5fdb6cfb83b83″

Answer: A
Clarification: Glycogen is an energy storage molecule in humans. Insulin is a protein that controls the storage of glycogen in the liver. Glycogen itself is made and stored in the cells of the liver and skeletal muscles. It is used as a long-term storage molecule in animals.

Fermentation Technology Multiple Choice Questions on “Microbiology – Product Spoilage”.

1. Who edited the second edition of ‘Brewing Microbiology’?
A. Rainbow
B. Priest and Campbell
C. Dolezil and Kirsop
D. Fernandez and Simpsonid5fdc03eface55″

Answer: B
Clarification: Priest and Campbell in 1996 edited the second edition of the ‘Brewing Microbiology’. The multi-authored book contains the text which is a real treasure-trove of information about what remains the poor relation of brewing science.

2. ‘The Beer is resistant to the microbial spoilage’. Who noticed the phenomena?
A. Fernandez
B. Simpson
C. Rainbow
D. Priestid5fdc03eface7e”

Answer: C
Clarification: Rainbow in 1981 noticed that the beer is resistant to the microbial spoilage. It is because of its low nutritional status, it’s content of products of yeast metabolism, its adverse values of pH and redox potential and its content of hop bitter substances. This explains the robustness of the beer to microbial spoilage.

3. Who correlated the resistance of spoilage to the beer parameters?
A. Rainbow
B. Priest and Campbell
C. Dolezil and Kirsop
D. Fernandez and Simpsonid5fdc03efacea4″

Answer: D
Clarification: Fernandez and Simpson in 1995 correlated the resistance of spoilage to the beer parameters. They used 14 strains of hop-resistant lactic acid bacteria and 17 different lagers. The spoilage was related to beer pH, nutrients, and undissociated forms of hop bitter acids and Sulphur dioxide.

4. Which of the following is a laboratory test used to describe bacteria?
A. Ouchterlony test
B. RPR test
C. Catalase test
D. Coombs testid5fdc03efaceb0″

Answer: C
Clarification: The catalase test is used to describe bacteria and also can be used to add value in routine microbiological troubleshooting. The Gram’s test can also be used to describe the bacteria. RPR test, Ouchterlony test, and Coombs test are not used in describing bacteria and are used in the Antigen-Antibody reaction.

5. Who devised Gram’s test?
A. Hans Christian
B. Rainbow
C. Fernandez
D. Jacobid5fdc03efacebb”

Answer: A
Clarification: A Danish bacteriologist, Hans Christian Gram in 1884 devised the Gram’s test who was working in the morgue in Berlin. Those bacteria which stain purple in color are Gram-positive bacteria and those which stain red or pink are Gram-negative bacteria.

6. Which of the following is a Gram-positive bacteria?
A. Acetobacter aceti
B. Escherichia coli
C. Gluconobacter oxydans
D. Streptococcus pneumoniaeid5fdc03efacec5″

Answer: D
Clarification: Streptococcus pneumoniae is a Gram-positive bacteria which take up purple stain from crystal violet when observed under the microscope. Other three bacteria belong to Gram-negative as they are observed as a pink stain when observed in the microscope.

7. Which of the following is used in the Gram’s staining?
A. Methylene blue
B. Safranin
C. Phenolphthalein
D. Methyl orangeid5fdc03efacecf”

Answer: B
Clarification: Safranin is used in Gram’s staining procedure. If it is a Gram-negative bacteria, it stains red. If it is a Gram-positive bacteria, it stains purple. The safranin is a counterstain and is lighter than crystal violet. It does not disrupt the colouration in Gram-positive cells while it decolorizes Gram-negative cells.

8. Who gave the explanation for hop resistance?
A. Hammond
B. Simpson
C. Sami
D. Fernandezid5fdc03efaced8″

Answer: C
Clarification: Sami et al. in 1997 gave a promising explanation for hop resistance. The presence or absence of a plasmid gene hor A correlates with hop resistance or sensitivity.

9. Which of the following is not reclassified into Saccharomyces cerevisiae?
A. S. tubidans
B. S. willianus
C. S. diastaticus
D. S. bayanusid5fdc03efacee2″

Answer: D
Clarification: Saccharomyces bayanus is not reclassified into Saccharomyces cerevisiae as it has remained unscathed by taxonomic changes. Saccharomyces tubidans, Saccharomyces ellipsoideus, Saccharomyces willianus, Saccharomyces diastaticus are now reclassified as Saccharomyces cerevisiae.

10. The killer yeasts produce _____________
A. Endotoxins
B. Exotoxins
C. Neurotoxins
D. Enterotoxinsid5fdc03efaceec”

Answer: B
Clarification: The killer yeasts produce exotoxins or ‘zymocins’ (to which they are immune) that kill the susceptible cells belonging to the same species. The Saccharomyces killer yeasts have been identified and best understood.

11. Which of the following is a real enemy of process and product hygiene?
A. Sources
B. Nitrosamines
C. Biofilms
D. Biogenic Aminesid5fdc03efacef5″

Answer: C
Clarification: Biofilms are the real enemy of process and product hygiene in brewing. The Biofilms or Biosponge provide both protection and nutrients for micro-organisms which are hostile in inappropriate environments.

12. Which of the following is not a biofilm?
A. Dental plaque
B. Slimes
C. Biofouling
D. Biogenic Aminesid5fdc03efaceff”

Answer: D
Clarification: Biogenic Amines are not a biofilm. Dental plaque, Slimes in water pipes and drains, and biofouling in cooling towers and heat exchangers are the classical biofilms. The biofilms are almost everywhere.

13. There are two drivers for consumer awareness of food safety.
A. True
B. Falseid5fdc03efacf08″

Answer: A
Clarification: Two drivers have been identified for the consumer awareness of food safety. First, the sensitization of consumer through scares such as BSE in beef products, benzene in carbonated drinks, etc. Second, the rapid development of analytical detection.

14. Nitrosamines are powerful carcinogens.
A. True
B. Falseid5fdc03efacf12″

Answer: A
Clarification: Nitrosamines are powerful carcinogens in animal systems and there has been indirect evidence that they are also involved in the development of human cancers. It was reported by Long in 1999.

Fermentation Technology Questions and Answers for Aptitude test on “Media for Industrial Fermentations – Minerals, Growth Factors and Buffers”.

1. Which of the following mineral is not required for microorganism?
A. Pb
B. K
C. S
D. Mgid5fdbac62ba61b”

Answer: A
Clarification: The minerals required to microorganisms are Potassium, Sulphur, Calcium, Chlorine, Phosphorus, Magnesium, Iron, etc. Lead (PB. is not required in media as it can be poisonous to microorganisms.

2. All microorganisms require minerals for growth and metabolism.
A. True
B. Falseid5fdbac62ba63e”

Answer: A
Clarification: All the microorganisms require minerals for proper growth and metabolism of the body. Minerals are the essential components added in the fermentation medium.

3. Which of the following trace element influence the production of Mitomycin?
A. Zn
B. Fe
C. Mn
D. Cuid5fdbac62ba64b”

Answer: B
Clarification: Iron influences the production of Mitomycin. Mitomycin is an important drug which is used to treat different types of cancer. Mitomycin is obtained from a soil fungus.

4. Which of the following resists the change in pH?
A. Buffer
B. Growth factors
C. Minerals
D. Inhibitorsid5fdbac62ba655″

Answer: A
Clarification: The solution which resists the change in pH of the media is called a buffer solution. It may be acidic or basic buffer solution. Buffers are required for maintaining the pH of the fermentation medium.

5. Which of the following is an example of a chelating agent?
A. Magnesium
B. EDTA
C. Ca
D. Glycerolid5fdbac62ba65f”

Answer: B
Clarification: The chelating agent is added to the medium to prevent the precipitation of metal phosphates. One of the examples of the chelating agent is EDTA.

6. The _____________ are not the growth factors.
A. Vitamins
B. Amino acids
C. Fatty acids
D. Carbohydratesid5fdbac62ba668″

Answer: D
Clarification: Vitamins, amino acids, fatty acids or sterols are the growth factors required for microorganisms to synthesize complements of cell components.

7. Which of the following is not an example of buffer?
A. CaCO₃
B. KH₂PO₄
C. NaH₂PO₄
D. NaOHid5fdbac62ba670″

Answer: D
Clarification: The examples of buffer solution are Calcium Carbonate (CaCO₃), Monosodium phosphate (NaH₂PO₄) and Monopotassium phosphate (KH₂PO₄).

8. Chlorine does not appear to play a nutritional role in the metabolism of fungi.
A. True
B. Falseid5fdbac62ba679″

Answer: A
Clarification: Foster in 1949 discovered that chlorine does not play a nutritional role in the metabolism of fungi. However, it is required by some bacteria.

9. Which of the following trace element influence the production of Gentamicin?
A. Mn
B. Zn
C. Fe
D. Coid5fdbac62ba681″

Answer: D
Clarification: Cobalt influences the production of Gentamicin. Gentamicin is used to fight against a broad range of bacterial infections. It works by stopping the growth of bacteria.

10. Which of the following growth factor is used in vinegar production?
A. Calcium Carbonate
B. Calcium Phosphate
C. Calcium Pantothenate
D. Calcium Hydroxideid5fdbac62ba689″

Answer: C
Clarification: Calcium pantothenate is used as a growth factor useful in the production of vinegar. Vinegar is useful in cleaning and washing hairs and also in the preservation of food.

11. Iron, Zinc, Copper influence the production of ____________
A. Protease
B. Neomycin
C. Citric acid
D. Penicillinid5fdbac62ba69d”

Answer: D
Clarification: Ferrous, Copper and Zinc are the trace elements that influence the production of Penicillin. Penicillin is an antibiotic which helps in the bursting cell wall of bacteria, i.e., cell lysis.

12. Which of the following is not the product of fermented fruit?
A. Wine
B. Whisky
C. Vinegar
D. Beerid5fdbac62ba6a6″

Answer: C
Clarification: Wine, Beer, Whisky, Brandy, Rum are the products which are obtained from the fermentation of fruits like grapes. Vinegar is produced by the fermentation of sugars by bacteria.

13. Which of the following is the first step in Fermentation Technology?
A. Media Formulation
B. Isolation of microbes
C. Constructing of fermenter
D. Preservation of microbesid5fdbac62ba6af”

Answer: A
Clarification: The first step of Fermentation Technology is isolation and detection of microbes of interest by various methodologies. Crowded Plate, Auxanographic techniques are used in the detection and isolation of organisms.

14. Which of the following reactor is best for the production of vinegar?
A. Batch reactors
B. Fed-Batch reactors
C. Continuous reactors
D. Submerged reactorsid5fdbac62ba6b7″

Answer: B
Clarification: The Fed-Batch reactor is useful in the production of vinegar because the fed-batch culture can maintain low ethanol concentrations.

15. Which of the following is not a non-essential mineral?
A. Molybdenum
B. Iron
C. Calcium
D. Cobaltid5fdbac62ba6c0″

Answer: C
Clarification: Calcium is used as an essential mineral in the fermentation media whereas iron, molybdenum, cobalt, etc. are non-essential media.

To practice all areas of Fermentation Technology for Aptitude test, .

Fermentation Technology Multiple Choice Questions on “Aeration and Agitation – Scale Up and Scale Down”.

1. What do you mean by ‘scale-up’?
A. Decreasing the scale of fermentation
B. Increasing the scale of fermentation
C. Decreasing the rate of agitation
D. Increasing the rate of fermentationid5fdc59703eba1″

Answer: B
Clarification: Scale-up means increasing the scale of fermentation. Increasing the scale of fermentation involves the increase in volume that is from small scale to large scale.

2. Which of the following is not a scale-up process?
A. Laboratory to pilot-scale
B. Pilot-scale to industrial-scale
C. Industrial to pilot-scale
D. Laboratory to industrial-scaleid5fdc59703ebc3″

Answer: C
Clarification: The scale-up process involves increasing the scale of fermentation by performing the experiments at laboratory or pilot scale and build large-scale fermenters with sufficient confidence that it will function properly.

3. Which of the following factors are not involved in the scale-up process?
A. Inoculum development
B. Sterilization
C. Temperature
D. Medium designid5fdc59703ebd3″

Answer: D
Clarification: The factors involved in the scale-up process are inoculum development, sterilization, and environmental parameters like temperature, pH, foam production, dissolved oxygen concentration, etc.

4. Who summarized the procedure for scaling up both Newtonian and non-Newtonian fermentations?
A. Hubbard
B. Fox
C. Lilly
D. Sinclairid5fdc59703ebdf”

Answer: A
Clarification: Hubbard et al. summarized the procedure for scaling up both Newtonian and non-Newtonian fermentations. They also proposed two methods to determine the large-scale conditions: Determine volumetric air flow and calculation of agitator speed.

5. Given below is a graphical representation of the scale-up window. What do the x and y-axis denote?

A. y – agitation, x – aeration
B. y – aeration, x – agitation
C. y – K_La, x – time
D. y – time, x – K_Laid5fdc59703ebea”

Answer: A
Clarification: The x-axis denotes aeration and y-axis denotes agitation. The graph shows the ‘scale-up’ window defining the operating boundaries for aeration agitation in the scale-up fermentation.

6. Which of the following is not a rule while doing scale-up studies?
A. The similarity in the geometry of the fermenter used
B. The similarity in the configuration of the fermenter used
C. There should a minimum of three or four stages of increment
D. Increasing power is a jump in scaleid5fdc59703ebf5″

Answer: D
Clarification: Increasing the power or magnitude is not a jump in scale. The jump in scale means performing laboratory-scale experiments at a pilot-scale or industrial scale-level. The geometry and the configuration of the fermenters used at both scales should be the same.

7. If scale-up studies failed, proceed with scale-down.
A. True
B. Falseid5fdc59703ec01″

Answer: A
Clarification: If the scale-up studies failed, then abort the system and proceed with scale-down. Abort the system with the economic loss to the investors or else find the cause which leads to the failure of the system.

8. What do you mean by ‘scale-down’?
A. Decreasing the scale of fermentation
B. Increasing the scale of fermentation
C. Decreasing the rate of agitation
D. Increasing the rate of fermentationid5fdc59703ec0b”

Answer: A
Clarification: Scale-up means decreasing the scale of fermentation. Decreasing the scale of fermentation involves the decrease in volume that is from large scale to small scale.

9. Which of the following is a scale-down process?
A. Laboratory to pilot-scale
B. Pilot-scale to industrial-scale
C. Industrial to pilot-scale
D. Laboratory to industrial-scaleid5fdc59703ec15″

Answer: C
Clarification: Scale-down is the situation where laboratory or pilot-scale experiments are conducted under the conditions which mimic the industrial-scale conditions. It is the most important for the development of a new product.

10. Which of the following is not an aspect in the context of scale-down?
A. Number of generations
B. Oxygen Transfer rate
C. Mixing
D. Temperatureid5fdc59703ec1f”

Answer: D
Clarification: The experiments in the context of scale-down methods is as follows:
i) Number of generations
ii) Oxygen Transfer Rate
iii) Mixing
iv) Medium design
v) Medium sterilization.

11. Who reviewed the scale-down methods?
A. Jem
B. Lilly
C. Fox
D. Sinclairid5fdc59703ec28″

Answer: A
Clarification: Jem in 1989 reviewed the scale-down methods which were used to mimic the industrial-scale level experiments at pilot-scale or laboratory-scale levels. It is important in the production of important products.

12. Shear conditions do not affect scale-up studies.
A. True
B. Falseid5fdc59703ec32″

Answer: B
Clarification: Environmental parameters like shear conditions, pressure, temperature, pH, etc. affect the scale-up studies. All these parameters are affected by agitation and aeration in terms of mixing of oxygen.

13. Which of the following process is used in the recovery of the product?
A. Downstream processing
B. Upstream processing
C. Chromatography
D. Treatment processid5fdc59703ec3c”

Answer: A
Clarification: Downstream processing has been used in the recovery of the product. It is also used in the purification of the product and manufacture antibiotics, antibodies, hormones, vaccines and is also used for the production of industrial enzymes.

14. Which of the following fermentation is carried out by yeast?
A. Lactic acid fermentation
B. Alcohol fermentation
C. Pyruvic fermentation
D. Acrylic fermentationid5fdc59703ec45″

Answer: A
Clarification: The fermentation which is carried out by yeast is called lactic acid fermentation. It is a process used for the conversion of glucose into energy and lactate. It occurs anaerobically.

Fermentation Technology Multiple Choice Questions on “Fermentation Biochemistry – Formation of Flavour Compounds”.

1. Which of the following metabolite does not impart flavour to beer?
A. Esters
B. Thiols
C. Carbonyls
D. Alcoholsid5fdc44bc6cc7e”

Answer: B
Clarification: Thiols does not impart flavour to the beer. Some aromatic alcohols, esters, carbonyls, and various sulphur-containing compounds are yeast metabolites that contribute to beer flavour. They are chemically diverse and includes organic acids and medium chain-length aliphatic alcohols.

2. Who reported flavours of more than 200 beer components?
A. Meilgaard
B. Ingram
C. Dombek
D. Reesid5fdc44bc6cca0″

Answer: A
Clarification: Meilgaard in 1974 reported the flavours for more than 200 beer components. He also reported that flavour thresholds varied to an enormous extent. Flavour is mainly influenced by the chain length of the molecule.

3. Which of the following is responsible for butterscotch flavour?
A. Dimethyl sulphate
B. Hydrogen sulphide
C. Diacetyl
D. Acetateid5fdc44bc6ccae”

Answer: C
Clarification: Diacetyl is responsible for imparting butterscotch or toffee flavour to the beer. It is also called as 2,3-Butanedione and is used to give butter-like or other flavours to the beer or other food products like popcorn.

4. Which of the following is used to give banana flavour?
A. Isoamyl acetate
B. Hydrogen sulphide
C. Dimethyl sulphate
D. Diacetylid5fdc44bc6ccba”

Answer: A
Clarification: Isoamyl acetate is responsible to impart banana flavour to the beer. It is also called as isopentyl acetate and is a colourless liquid that is slightly soluble in water. It is a banana smelling ester which is used in many fragrance and flavour imparting departments in industries.

5. Which of the following is responsible for apple flavour?
A. Isoamyl acetate
B. Hydrogen sulphide
C. Dimethyl sulphate
D. Ethyl acetateid5fdc44bc6ccc4″

Answer: D
Clarification: Ethyl acetate is responsible for imparting apple flavour to the beer and other food products. It is also used in glues, nail polish removers, decaffeinating tea and coffee. It is an inflammable solvent.

6. Which of the following has goat-like aromas?
A. Caprylic acid
B. Succinic acid
C. Malic acid
D. Formic acidid5fdc44bc6ccce”

Answer: A
Clarification: Caproic and Caprylic acid has an unpleasant smell responsible for goat-like aromas. It is also found in the milk of many mammals, coconut oil and kernel oil. Caprylic acid has antifungal, antiviral, antibacterial properties and is useful in the treatment of many infections like a vaginal yeast infection.

7. Which of the following acts as an osmoprotectant?
A. Glycogen
B. Glycerol
C. Acetic acid
D. Starchid5fdc44bc6ccd7″

Answer: B
Clarification: Glycerol acts as an osmoprotectant. It contributes to the body and mouth-feel of beers at concentration 1-2 g/l. It also has a role in redox control. The elevated glycerol concentrations induce the cultivation of yeast with low activity of water.

8. Which of the following imparts rose flavour?
A. Isobutyl acetate
B. Isoamyl acetate
C. Phenylethylacetate
D. Caproateid5fdc44bc6ccf3″

Answer: C
Clarification: 2-Phenylethylacetate is responsible for imparting rose flavour to the beer and other food products. It also imparts honey and apple aroma to the food products. It is found in many fruits and is colourless liquid.

9. Which of the following is responsible for aldehyde reduction?
A. ADH II
B. ADH I
C. ADH III
D. ADH IVid5fdc44bc6ccfd”

Answer: B
Clarification: Alcohol dehydrogenase coded by ADH I is responsible for the reduction of aldehyde. The products of ADH II and ADH III, respiratory alcohol dehydrogenase, are not involved in the reduction of aldehyde.

10. Which of the following is an alternative to diacetyl for imparting a yellow colour to the beer?
A. 2,3-Pentanedione
B. 2,4-Pentanedione
C. 2,2-Pentanedione
D. 1,2-Pentanedioneid5fdc44bc6cd06″

Answer: A
Clarification: 2,3-Pentanedione is used for imparting a yellow colour to the beer and other food products. It is used as an alternative if diacetyl is not available. Both are strong flavouring substances and impart butterscotch flavour to the compounds.

11. Sulphite acts as _______________
A. Oxidant
B. Anti-oxidant
C. Anti-inflammatory
D. Anti-agingid5fdc44bc6cd10″

Answer: B
Clarification: Sulphite acts as a natural anti-oxidants. They are added to fermenting alcohol beverages because it is more toxic to bacteria and molds than to yeast. In addition to that, it also acts as anti-oxidants in many food products.

12. Acetaldehyde is ___________ toxic to cells.
A. Less
B. Not
C. Highly
D. Moderateid5fdc44bc6cd19″

Answer: C
Clarification: Acetaldehyde is highly toxic to cells. It was reported by Jones in 1989. Its ability to form Schiff bases with amino acid residues leads to the inactivation of enzymes and also disrupts the synthesis of proteins and nucleic acids.

13. Oxygen is used for the synthesis of sterols.
A. True
B. Falseid5fdc44bc6cd22″

Answer: A
Clarification: Oxygen is required in the brewery fermentation to yeast to allow the synthesis of sterols and unsaturated fatty acids which are essential components of the membrane of yeast. Yeast is also capable to grow under strictly anaerobic conditions.

14. Steam beer is a bottom-fermented beer.
A. True
B. Falseid5fdc44bc6cd2c”

Answer: B
Clarification: Steam beer is the top-fermented beer. It was originated in California, USA. It is prepared with bottom yeast at a relatively higher temperature. It is well-hopped beer with amber colour and highly carbonated.