Page 420 - AWSAR 2.0

396 || AWSAR Awarded Popular Science Stories - 2019
‘What is this?’
‘Pillu wait, I am coming to that. This dryer has a continuous system to produce low-humidity air, which means air with less moisture or dry air. This dryer uses dry air to remove water from apples. We can dry any food material in this dryer at a lower temperature, slightly
above the room temperature.
‘Oh... it sounds so cool, Ma.’
‘Wait, I will draw a picture of this dryer so that you will understand it better. See how it looks?’
‘Wow! It looks so interesting and colourful, but I couldn’t understand how it works.’
‘Pillu see here in picture (A). On these trays, I keep apple slices, and trays have small holes for air movement. When I switch on the system, dry air comes into this
chamber and takes out water from the apple slices quickly. It happens because apples have more water, while dry air has less water.
‘What! How dry air can take out
water from apples?’
‘Pillu, let me explain. See, during
winter, your skin becomes dry,
and you feel itchy. Do you
know why it happens? Actually,
during the winter, the air
around us has less water, and
it removes water from your skin,
making it dry because your
body has more water than air. So, apples also get dried in the same way.’
‘Mamma, what is this box?’ (Points to air dehumidification system)
‘Pillu, this box will make the air dry; it is used
for drying apples.’
‘How does it dries the air, Ma?’ I had expected this question! I had seen him many times disassembling his toys to satisfy his curiosity to know what was there inside. After this, not a single toy worked properly! ‘Pillu, tell me what happens if you overfill a glass with water?’ ‘Excess water will spill out ... Mamma.’
‘Correct, Pillu! Similarly, dry air also can take water from apple slices until it is full. We call it saturated air. After this point,
air can’t take out any more water from apple slices. Further, saturated air comes to the air
We can do that Pillu, but frying reduces sweetness and makes them charred like caramel candy. It also makes apples unhealthy as they will absorb too much oil.’‘Is there any way out to dry apples without hot or cold conditions, Mamma? Can’t you do something in your lab to dry apples?