MANGOES AROUND THE YEAR-TEXT

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.

There are three types of microorganisms that cause food spoilage -- yeasts, moulds and bacteria. 

yeasts and moulds can thrive in high acid foods like fruit, tomatoes, jams, jellies and pickles.

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.

Fungal Spoilage: Blue mould rot in tomato caused by Penicilliumi spp,

Watery soft rot in apple caused by Sclerotinia sclerotiorum.

Bacterial Spoilage: Soft rot in tomato caused by Erwinia carotovora.

Enzymes:

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.

Oxidation by air:

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.

Biji returned the bread:

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.

How does food get spoilt?

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.

Spolit food it unfit for consumption. It taste bad and can causes disease.

Therefore, it has to be prevented from spoilage. This prevention is termed as preservation.

PRESERVATION OF FOOD:

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.

Summer treat – Mamidi tandra:

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.”

Both the brothers quickly agreed to help. The next day both the children went to the market with their father. They bought a mat woven from the leaves of a palm tree, poles of casuarinas tree, string made of coconut husk, some jaggery and sugar. Amma found a sunny place in the backyard. Both the brothers made a high platform by using poles. They spread out and tied the mat on that platform.

The next day, Appa chose the most ripe mangoes.  They took out the mango pulp into a large pot. Then they strained the pulp through a fine muslin cloth, to remove the fibres from the pulp.

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.

After some days Amma said, “The mamidi tandra is ready, we can

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

SUPER SENSES TEXT

SUPER SENSES

ENVIRONMENTAL STUDIES

CBSE-V

Children - Has this ever happened to you:

You were eating in the playground, an eagle flew down and took away your roti. As you walked softly past a sleeping dog, its ears shot up at once.

You dropped something sweet on the ground and within minutes many ants collected around it.

Why does it happen:

Animals also have different senses. They can see, hear, taste, smell and feel. Some animals can see their prey from far away. Some can hear even the faintest sound. 

Some animals can find their friends by their smell. The animal world is full of examples of amazing senses!

SENSE ORGANS

The sense organs are eyes, ears, tongue, skin, and nose. There are five senses: sight, hearing, taste, smell and touch.

How did the ant recognise a friend:

An ant was going along on the ground. It saw a group of ants coming from the other side. The first ant quickly came back to its hole. The ant guarding the hole recognised it and let it in.

Many years ago a scientist did many experiments like this. He found out that as the ants move, they leave a smell on the ground. The other ants follow the smell to find the way.

Now can you guess why the ants behaved like that when you blocked their path? Some male insects can recognise their females by their smell.

Have you ever been troubled by mosquitoes. Just think, how do they know where you are? Mosquitoes can find you by the smell of your

body. They also find you by the smell of the sole of your feet and the heat of your body.

I am a silk worm. I can find my female worm from many kilometres away by her smell.

Dogs mark out their own area on the road. They can make out if another

dog has come into their area by the smell of its urine or potty (latrine).

Why so:Today Rajni had to go out for some  important work. She had to leave her sixmonth old son Deepak with her sister Sushila. Sushila also has a baby of the same age. 

It was funny that both the babies did potty at the same time. She happily cleaned her daughter but when she was cleaning her sister’s son Deepak, she covered her nose with her dupatta (scarf).

Most of the birds have their eyes on either side of the head.Their eyes can focus on two different things at a time. When they look straight ahead, both their eyes focus on the same object. 

You must have seen birds moving their neck very often. Do you know why? In most of the birds, eyes are fixed and cannot move. So birds have to turn their heads to see around.

Some birds like kites, eagles, vultures can see four times as far as we can. These birds can see things from a distance of eight metres what we can see from a distance of two metres._ Now can you guess from what distance can an eagle in the sky can see a roti on the ground?

Do animals see colours:

Animals cannot see as many colours as we can. See how things in these pictures will be seen by some animals. 

It is believed that animals that are awake in the daytime can see some colours. Those animals that are awake at night can see things only in black and white colours.

Sharp ear:

In Class IV, you read that we cannot easily see birds’ ears. Their ears

are small holes covered with feathers.

Sounds send messages:

High up on a tree, a langur warns others of dangers like a tiger or leopard. The langur does this by making a special warning call. 

Birds also give alarm calls to warn about the danger. Some birds even have different sounds for different kinds of dangers.

For example, there is a different warning call if the enemy is coming from the sky or if the enemy is on the ground. When any animal gives the warning call, all the animals in that area understand the danger signal.

Some animals start behaving in a different way when an earthquake or storm is about to come. People who live in forests and can observe such behaviour of animals come to know of the danger.

In December 2004, few tribes that live in the forests of the Andaman Islands noticed the animals behaving in a different manner. They guessed some danger. So they moved away to a safer part of the island. Soon after, the islands were hit by the tsunami but these people were saved.

Dolphins also make different sounds to give messages to each other. Scientists believe that many animals have a special language of their own.

Say it with sounds:

Just like birds and dolphins you can also make your own language of sounds for giving messages. Remember you have to talk to your friends with only sounds and no words. How and when will you need to give an alarm call? For example, when the teacher is coming to the classroom!

Sleeping-waking:

Some animals go into a long, deep sleep in certain seasons. Then they are not seen for many months.

Sloth:

It looks like a bear but is not. It is a sloth. It spends almost 17 hours a day sleeping while hanging upside down on a tree branch. The sloth eats the leaves of the same tree on which it lives.

It hardly needs anything else. When it has eaten enough leaves from that tree, it moves to the nearby tree. Sloths live for about 40 years and in that time they move around only eight trees. Once a week it comes down from the tree to relieve itself.

A tiger can see six times better at night than most of us humans. The tiger’s whiskers are very sensitive and can sense the movements or vibrations in air. 

They help the tiger move in the dark and find its prey. A tiger’s sense of hearing is so sharp that it can make out the difference between the rustling of leaves and the sound of an animal moving on the grass.

The ears of the tiger can move in different directions and this helps to catch the sounds from all around. Tigers make different sounds for different purposes like when it is angry or to call out to a tigress. It can also roar or snarl. It’s roar can be heard upto 3 kilometres away.

Each tiger has its own area which may cover several kilometres. Tigers mark their area with their urine. A tiger can at once come to know if there is another tiger in its area by the smell of the urine. A tiger will avoid going into another tiger’s area.

The number of tigers and many other animals in our country is reducing. There is a danger that some of them will soon disappear. To protect the animals, our government has made some forests as protected areas. 

Some of them are the Jim Corbett National Park in Uttrakhand and ‘Ghana’ in Bharatpur district of Rajasthan. In these areas nobody can hunt animals or destroy the jungle.

THANKYOU,

NANDITHAAKUNURI

SUPER SENSES ENVIRONMENTAL STUDIES - CLASS V (CHAPTER-1 CBSE) from Research Scholar