FOOD PROCESSING AND PRESERVATION
DRYING AND DEHYDRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Which of the following is not a phenomenon that occurs during the 1st drying phase (pretreatment phase)?
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The initial moisture content of the feed is high.
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The surface of the food is very wet.
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The surface temperature of the food is close to the dry bulb temperature.
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The drying rate gradually increased.
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Explanation:
Detailed explanation-1: -Explanation: During second falling drying rate period, the moisture transfer is due to the liquid diffusion, capillary movement, and vapor diffusion because the drying rate becomes independent of conditions outside the solid.
Detailed explanation-2: -These mechanisms fall in to three classes: (i) evaporation from a free surface (ii) flow as a liquid in capillaries, and (iii) diffusion as a liquid or a vapour. The first mechanism follows the laws for heat and mass transfer for a moist product.
Detailed explanation-3: -The rate of drying is determined by the moisture content and the temperature of the grain and the temperature, the (relative) humidity and the velocity of the air in contact with the grain.
There is 1 question to complete.