This set of Basic Food Engineering Questions & Answers focuses on “Principles of Refrigerated Gas Storage of Foods-2”.
1. Which of the following is NOT delivered by the modified atmosphere (MA) or controlled atmosphere (CA)?
a) Delay ripening of fruits
b) Retard spread of diseases
c) Toughing
d) Incidence of storage disorders
View Answer
Explanation: Toughening and yellowing are NOT delivered by the modified atmosphere (MA) or controlled atmosphere (CA). The other positive things like delaying ripening of fruits, retarding spread of diseases and incidence of storage disorders are delivered.
2. Which of the following variables affect gas exchanges into and out of the package?
a) Weight of apples
b) Ethylene concentration
c) Structure of the packaging film
d) All of the mentioned
View Answer
Explanation: Structure of the packaging film affect gas exchanges into and out of the package. Weight of apples and Ethylene concentration affect respiration.
3. Which of the following is NOT the correct method to enhance storage?
a) Reducing pressure
b) Increasing ethylene
c) Decreasing respiration
d) None of the mentioned
View Answer
Explanation: Ethylene given out by produce should be reduced to enhance storage/life.
4. Statement 1: Sub atmospheric storage involves ventilating the produce with air saturated with water vapor by continuously evacuating the container with a sealed vacuum pump.
Statement 2: Under hypobaric storage, a gas in equilibrium with its surroundings will have its outward diffusion rate proportional to concentration gradient and diffusivity.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Sub atmospheric storage involves ventilating the produce with air saturated with water vapor by continuously evacuating the container with a sealed vacuum pump. Under hypobaric storage, a gas in equilibrium with its surroundings will have its outward diffusion rate proportional to concentration gradient and diffusivity.
5. Under hypobaric storage, when gas is in equilibrium with its surroundings, the diffusivity _____ and concentration gradient _____
a) Increase by ten folds, decreases to one-tenth
b) Decreases to one-tenth, increase by ten folds
c) Stays constant, stays constant
d) None of the mentioned
View Answer
Explanation: Under hypobaric storage, when gas is in equilibrium with its surroundings, the diffusivity increase by ten folds and concentration gradient decreases to one-tenth. This is because the concentration difference reduces to a large extent and hence the gradient decreases but since a new equilibrium is established and this always happens, the diffusivity increase.
6. Statement 1: Under hypobaric storage, the gas always attains equilibrium with its surroundings.
Statement 2: Hypobaric storage is a continuous process.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Under hypobaric storage, the gas always attains equilibrium with its surroundings. Hypobaric storage is a continuous process.
7. Statement 1: Under hypobaric storage, oxygen content is reduced to reduce the rate of synthesis of volatile.
Statement 2: Altering respiration can help in decreasing the production of carbon dioxide.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Under hypobaric storage, oxygen content is reduced to reduce the rate of synthesis of volatile. Altering respiration can help in decreasing the production of carbon dioxide.
8. Which of the following is true with respect to volatile by controlling oxygen content in storage?
a) Lowing in endogenous concentration increases rate of volatile formation
b) Anaerobiosis favors its production if it is a highly reduced compound
c) Limiting the amount of energy available
d) All of the mentioned
View Answer
Explanation: All of the mentioned is true with respect to volatile by controlling oxygen content in storage.
9. Statement 1: A gas atmosphere containing 20% CO2 is effective in inhibiting slime-producing bacteria.
Statement 2: Meat can be preserved by protecting it from oxygen as the majority of bacteria grow in that atmosphere.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: A gas atmosphere containing 20% CO2 is effective in inhibiting slime-producing bacteria. Meat can be preserved by protecting it from oxygen as majority of bacteria grow in that atmosphere.
10. Statement 1: Influence of bacteria has more effect on the storage of food than the pH control.
Statement 2: Meat color is due to the presence of _____
a) True, myoglobin
b) True, haemoglobin
c) False, myoglobin
d) False, haemoglobin
View Answer
Explanation: Influence of bacteria has more effect on the storage of food than the pH control. Meat color is due to the presence of myoglobin.
11. Meats stored in _____ environment have a better color than _____
a) CO2, O2
b) O2, CO2
c) CO2, N2
d) N2, O2
View Answer
Explanation: Meats stored in O2 environment have a better color than CO2. This is because auto-oxidation of myoglobin in the meat takes place which is responsible for the fresh color.
12. Which of the following statements is true?
a) Polyethylene films have a good heat-sealability
b) Polyvinylidene chloride films are gas and water vapor impermeable
c) Nylon films have high physical strength
d) All of the mentioned
View Answer
Explanation: Polyethylene films have a good heat-sealability. Polyvinylidene chloride films are gas and water vapor impermeable. Nylon films have high physical strength.
13. Three level packaging is done for rice. Which bag is for quality control?
a) Inner most bag 1
b) Middle bag 2
c) Outermost bag 3
d) All of the mentioned
View Answer
Explanation: Bag 1 is moisture permeable and hence drains out the moisture from the grain. 2nd one is for quality control and the 3rd prevents the 2nd one from breakage.
14. Statement 1: Under water storage is more effective than that in the air.
Statement 2: Adsorption of CO2 on the surface of grains is a reversible process.
a) True, False
b) True, True
c) False, False
d) False, True
View Answer
Explanation: Under water storage is more effective than that in the air. Adsorption of CO2 on the surface of grains is a reversible process.
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