Fruits stored in a cold chamber exhibit longer storage life because
- A.exposure to sunlight is prevented
- B.concentration of carbon dioxide in the environment is increased
- C.rate of respiration is decreased
- D.there is an increase in humidity
Correct answer
Explanation
The correct answer is C, the rate of respiration is decreased. A harvested fruit is still a living tissue that keeps respiring, using up its own sugars and acids and giving off heat, carbon dioxide and ethylene. Every such reaction is enzyme driven, and the speed of an enzyme reaction falls sharply as the temperature falls. Cold storage at a few degrees above freezing therefore slows respiration, delays ripening and softening, and at the same time slows the growth of spoilage bacteria and moulds, so the fruit keeps much longer. Option A is wrong because darkness by itself does not preserve a fruit; fruit kept in a dark but warm room spoils quickly. Option B is wrong because raising carbon dioxide is a separate technique, controlled atmosphere storage, and is not what a plain cold chamber does. Option D is wrong because higher humidity only checks shrivelling from water loss and in fact favours mould growth, so it cannot be the reason for longer storage life.
Read the full article: Food Preservation, Adulteration and Food Safety Notes
Practice Questions
View allThe adulteration of mustard oil with argemone oil causes which disease?
- A.Lathyrism
- B.Epidemic dropsy
- C.Fluorosis
- D.Minamata disease
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Argemone mexicana, the prickly poppy known in India as satyanashi, has seeds that look very like mustard seeds, so its oil is a classic adulterant of mustard oil.
Read the full explanation →Lathyrism in human beings is caused by the prolonged consumption of which of the following?
- A.Khesari dal
- B.Argemone seeds
- C.Metanil yellow
- D.Chicory
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Khesari dal, botanically Lathyrus sativus and also called grass pea, is a hardy pulse that survives drought and is therefore sometimes mixed with arhar dal or besan.
Read the full explanation →In the high-temperature short-time (HTST) method of pasteurisation, milk is heated to about:
- A.63 degrees Celsius for 30 minutes
- B.72 degrees Celsius for 15 seconds
- C.100 degrees Celsius for 10 minutes
- D.150 degrees Celsius for 2 seconds
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Pasteurisation is not sterilisation: it is a mild heating that kills disease-causing organisms such as Mycobacterium tuberculosis, Salmonella and Brucella and most spoilage bacteria, while leaving the taste and nutritive value of milk largely unchanged.
Read the full explanation →Lyophilisation, used to make instant coffee and to preserve vaccines, is the technical name for which process?
- A.Pasteurisation
- B.Freeze-drying
- C.Canning
- D.Irradiation
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In lyophilisation the material is first frozen and then placed under a strong vacuum, so that the ice changes directly into vapour without passing through the liquid state.
Read the full explanation →Which of the following is a Class I preservative under Indian food standards?
- A.Sodium benzoate
- B.Sulphur dioxide
- C.Common salt
- D.Potassium sorbate
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Indian food standards divide preservatives into two classes. Class I preservatives are the natural ones that cooks have always used, and no limit is placed on the quantity: common salt, sugar, dextrose, spices, vinegar or acetic acid, honey and edible vegetable oils.
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