MANGOES AROUND
THE YEAR
ENVIRONMENTAL STUDIES
CBSE-V
Children
in this lesson we are going to learn about Spoilage and wastage of
food,preservation of food(drying and pickling).
Food
spoilage means the original nutritional value, texture, flavour of the food are
damaged, the food become harmful to people and unsuitable to eat.
Bacteria are
round, rod or spiral shaped microorganisms. Bacteria may grow under a wide
variety of conditions. There are many types of bacteria that cause spoilage.
Watery
soft rot in apple caused by Sclerotinia sclerotiorum.
Bacterial
Spoilage: Soft rot in tomato caused by Erwinia carotovora.
Enzymes
are proteins found in all plants and animals. If uncooked foods are not used
while fresh, enzymes cause undesirable changes in colour, texture and flavour.
Enzymes are destroyed easily by heat processing.
Atmospheric
oxygen can react with some food components which may cause rancidity or color
changes.
Microorganisms,
specifically bacteria, molds, and yeasts, can cause food to spoil.
For example, microorganisms that break down fats in unsalted butter can cause
it to become rancid. Bacteria that breaks down protein in meat (proteolytic
bacteria) and results in foul odors.
Aman’s
Biji went to the market to buy bread. The shop was very crowded. The shopkeeper
picked up a packet of bread and gave it to Biji. She looked at it and returned
it immediately.
The
whole class can do this experiment together. Take a piece of bread or roti.
Sprinkle a few drops of water on it, and put it in a box. Close the box. See
the bread or roti everyday until you find some changes on it.
Make
this table on a chart paper and put it up in the classroom. Fill up the chart
every day after discussing the changes seen.
So
children the fod gets spoiled easily.bacteria and fungi grow well at room
temperature in the presence of moisture. Cereals and pluses do not get spoiles
easily as there is no moisture in them.
Therefore,
it has to be prevented from spoilage. This prevention is termed as
preservation.
Food
can be presrved by the following methods. We can stored food by this following
five methods.
1.
Cooling Or Refrigeration
2.
Jellying
3.
Pickling
4.
Drying
Or Dehydration
5.
Tetra packing
6.
Canning
1.
Cooling Or Refrigeration: food spoiling bacteria do not grow in cold
temperature. So, this is a common way of preservation.
2.
Jellying: fruits like strawberries, mangoes and pine apples are
preserved by this method. The fruit pulp is a boiled in sugar syrup. Sugar acts
as a preservative. Jams and fruits are preserved in this way.
3.
Pickling: seasonal fruits like mangoes, lime, amla and garlic are
preserved by pickling. For this we add `salt, vinegar and oil are used as
preservatives in pickles.
4.
Drying Or Dehydration: the food can also be preserved by drying in the
stem. Spices
like chillies and ginger, papadas and food grains are preserved by drying in
the sun. Dry means removing the moisture content of the food which promotes the
growth of bacteria.
5.Tertra
packing : this method is similar to canning but is used for liquids. Here,
the food is heated to very high temperature and then packed in terapacks .
Ex:
milk, juice, oil, and ghee are stored in this way.
6.
Canning:
in this process the food is heated temperature to kill the food spoiling
bacteria and then stored in air tight cans or bottles.
Food
preserved helps in preventing wastage of food from the spoiling. It also helps
us to store food and use it when it required whole the year. All
preserved foods have a shelf life. While buying and using preserved food, we
should check the expiry date mentioned at the label of the product.
Chittibabu
and Chinnababu live in Atreyapuram town in Andhra Pradesh. The brothers spend
the summer holidays playing in the mango garden, when the trees are full of
fruits. They also like to eat unripe mangoes with salt and chilly powder.
At
home, their mother cooks unripe mangoes in different ways. She also makes many
kinds of mango pickles. The pickles last through the year until the next mango
season. One
evening, while having food Chinnababu asked, “Amma, we have so many mangoes.
Make some mamidi tandra (aam papad) from them.”
Their
father said, “Making mamidi tandra needs four weeks of hardwork. If you both
promise to help us everyday for the next four weeks, we can together make the
mamidi tandra.”
Then
Chittibabu crushed the gur (jaggery) till there were no lumps. They added the
jaggery and sugar in equal amountsto the pulp.
Chinnababu
mixed the jaggery and sugar well with a big spoon. Amma then spread this pulp
into a thin layer over the mat. The thin layer was left to dry in the sun. In
the evening, they covered the mat with a clean saree to avoid any dust.
The
next day they again took out some mango pulp. They added jaggery and sugar into
the pulp. Then they spread the pulp over the previous day’s layer. This work
was given to both the brothers. Both of them together spread many layers over
it.
For
the next four weeks they hoped that it would not rain. For four weeks, they
added layer after layer until the jelly grew four centimetres thick and looked
like a golden cake.
take
it out and cut it into pieces tomorrow.” The next day, the mat was brought down
from the platform.
Mamidi
tandra was cut into smaller pieces. The brothers tasted it. It was tasty.
Chhinnababu said, “Wow, how tasty! After all we have also helped in making it.”
THANKYOU,
NANDITHA AKUNURI
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