1. What factors affect enzymatic browning? a) Phenolic compounds b) Temperature
c) pH d) Phenolic compounds, temperature, and pH
o Answer: d) Phenolic compounds, temperature, and pH 1.
2. How does sugar slow enzymatic browning? a) Reduce oxygen diffusion b) Increase
the oxygen diffusion c) Reduce carbon dioxide diffusion d) Increase carbon dioxide
diffusion
o Answer: a) Reduce oxygen diffusion 1.
3. How does saltwater prevent enzymatic browning? a) Inhibit the polyphenol
oxidase b) Activate the polyphenol oxidase c) Reduce carbon dioxide diffusion d)
Increase carbon dioxide diffusion
o Answer: a) Inhibit the polyphenol oxidase 1.
4. What is the purpose of enzymatic browning? a) Ripening b) Metabolism c) Protein
denaturation d) Metabolism and protein denaturation
o Answer: d) Metabolism and protein denaturation 1.
5. True or False: Pyrocatechol derivatives are one of the substrates for enzymatic
browning, and the enzyme reacts with only air to cause brown discoloration.
o Answer: b) True, True 1.
6. Which of the following is used for measuring enzymatic browning? a) Browning
indicators b) Cellulose metabolism c) Ethylene production d) Protein denaturation
o Answer: a) Browning indicators 1.
7. Does vinegar prevent oxidation?
o Answer: b) False 1.
8. How can enzymatic browning be controlled? a) Prevention of oxygen exposure b)
Unclarified pectin c) Use of low temperature d) Thermal treatment, prevention of
oxygen exposure, use of low temperature
o Answer: d) Thermal treatment, prevention of oxygen exposure, use of low
temperature 1.
9. At what pH range is polyphenol oxidase activated? a) 5-7 b) 3-5 c) 1-3 d) 4-5
o Answer: b) 3-5 1.
10. Which of the following is not used in preventing enzymatic browning? a)
Reducing agents b) Chelating agents c) Acidic agents d) Basic agents
o Answer: d) Basic agents 1.
11. What is phenylalanine ammonia lyase? a) Reducing agents b) Chelating agents c)
Enzyme in phenolic biosynthesis d) Basic agents
o Answer: c) Enzyme in phenolic biosynthesis 1.