Plant food
This module will discuss food from plant sources.
Food.
Nutrition.
Food grains.
Cereals.
Wheat.
Rice.
Maize.
Grain legumes or pulses.
Vegetable oil.
Vegetables.
Fruits.
Nuts.
Herbs and spices.
Food preservation.
Food.
Food is an essential need for all living beings.
Food provides the energy, and other essential requirements, for life.
Animals spend most of their waking hours, foraging for food.
Our ancestors also spent most of their time, looking for food.
The first major revolution, for human beings, was the agricultural revolution.
Before human beings learnt to farm, they wander from place to place,
looking for food.
It is only during the agricultural revolution, that human beings,
started to settle down.
In many ways, this was the beginning of civilised life.
This stage of human evolution, started only about 10000 years ago.
Banks of rivers, were a good place, to practice agriculture.
Human beings learnt to tend to the fertile soil, and plant seeds.
Early civilisation, developed along the banks of rivers.
For example, ancient Egyptian developed, on the banks of the river Nile.
The seeds for agricultural crops, originally came from wild plants.
Overtime human beings learnt to cultivate, many kinds of crops.
Now, we produce a wide variety of food crops.
Modern agriculture now produces hundreds of types, of food grains, vegetables,
fruits etc.
There is one more development, which took place, which differentiates human beings.
Human beings were the only species, which cooked their food.
This enabled us to have a larger variety of food choices.
It also helped us to digest the food easily.
Some scientists believe, that eating cooked food, helped our brains to develop.
Cooking also resulted in developing thousands of types of recipes.
Most of us, today are concerned about the taste of food,
rather than the nutrition value, of the food.
Nutrition.
We are pampered with a wide variety of food dishes.
Different countries have evolved different food cuisines.
Within the country, there could be a wide variety of regional flavors.
With super markets and restaurants, we are spoilt for a choice of food variety.
Food is the source of nutrients for the body.
The body needs nutrients, for metabolism.
Nutrients, provide the structural building blocks for cells.
We need energy, just to live.
Nutrients provide this energy, for living.
When we do physical work, or when we play, we need energy.
The energy for day to day living, is provided by nutrients.
Surprisingly, the body needs and absorbs, a very limited number of nutrients.
Whatever exotic dishes we may eat, in any part of the world,
the body finally extracts some very limited nutrients from the food.
The nutrients extracted from food are:
Carbohydrates.
Proteins.
Lipids or fats.
Vitamins.
Minerals.
Apart from these nutrients, the body also extracts,
water and dietary fibre, which are essential for life.
The process of extracting nutrients from food, is called digestion.
The digestive system, responsible for digestion,
is an important system, in the human body.
The nutrients have distinctive properties.
Carbohydrates, proteins, fats and water, are called macronutrients.
We need significant amount of macronutrients.
The structural elements of cells, are provided by macronutrients.
Energy is also provided by macronutrients.
The amount of energy provided, by food, is measured in kilo calories.
One kilo calorie is also called as a food calorie.
A food calorie, is spelt with a capital C.
Carbohydrates and proteins, provide about 4 kilo calories,
or 4 food calories, of energy per gram.
Lipids or fats, provided about 9 kilo calories,
or 9 food calories per gram.
Vitamins and minerals are called as micronutrients.
We require only very minute quantities of micronutrients.
Usually trace amounts in micrograms, is sufficient.
Vitamins and minerals, do not provide energy.
Vitamins and minerals, are however very essential for many other life processes.
Water is also essential for life.
A large percentage of our body, comprises of water.
Many of the cell metabolisms, take place in the presence of water.
Dietary fibre aids the digestion process.
Food grains.
Before the advent of agriculture, about 10000 years ago,
we were hunter gatherers.
We used to hunt animals,
and gather wild plants for food.
After we learnt agriculture, we learnt to grow the food, we need.
We used to gather seeds from wild plants, and sow them in naturally fertile soil.
Some of these wild plants, were grass plants, with seeds.
These seeds were the original food grains, like wheat and rice.
We learnt to harvest the plants, and separate the seeds, which became food grains.
By selectively sowing, some of the best of the harvested food grains,
we were able to cultivate, better and better quality food grains.
The wheat and rice, and other food grains, we eat today,
are the result of many generations, of selective breeding.
Food grains became the first most important man made food.
Food grains have good nutrient value.
There is another reason, food grains became very popular,
in many civilisations.
Food is normally perishable.
Food grains, once harvested, could be stored for extended periods of time.
Typically harvesting was done, once in a year.
The stored food grains, could be used through out the year.
The stored grains could also be transported,
and traded for other goods.
These factors, were major advantages of agriculture.
No wonder, it was called as the agricultural revolution.
Food grains used to be also milled, to be used as flour.
Some grains, called oil seeds were pressed to extract oil.
Food grains continued to be the dominant source of food,
for human beings till today.
Food grains comprise of cereals like wheat,
and legumes like soya beans.
Cereals.
All cereal crops are members, of the grass family.
They were originally wild grass.
Selective breeding over many centuries, has resulted in the high quality grains,
that we produce today.
We are moving towards large scale production of food crops,
using modern machinery, fertiliser and insecticides.
Agriculture is now an industry.
Most of the food grains produced today, come from industrial agriculture.
Some commonly used cereals are:
Wheat.
Rice.
Maize or corn.
Millets.
Oats.
Barley.
The main components of a cereal are:
Husk.
Germ.
Endosperm.
Bran.
Husk.
The husk is the outer shell or coating of a seed.
It provides protection for the seed.
For use as a food grain, cereals are milled.
The husk is removed by milling, in cereals.
Germ.
The germ in the cereal, is the reproductive embryo part of the seed.
It is the part that germinates and grows into a plant.
If the germ is retained in milling, it is called as a whole grain.
The germ is rich in polyunsaturated fats.
Polyunsaturated fats are good for health.
Unfortunately, the germ portion of the cereal, spoil easily,
and is not suitable for long term storage.
Commercial cereals, normally remove the germ during milling.
Endosperm.
Endosperm is the tissue, produced in the seed.
It surrounds the embryo, and provides nutrition to it.
Typically the endosperm contains starch.
It can also have proteins, and fats.
The endosperm, is the main source of nutrition, in cereals.
For example, it is the endosperm, of wheat and rice,
which we consume, as a staple food.
Some endosperm contains fats in the form of oil.
This oil is extracted, and used in cooking.
Such grains are called as oil seeds.
Sunflower seed is an example of an oil seed,
from which sunflower oil is extracted.
Wheat.
Wheat is one of the earliest cereal, first cultivated in the near east.
It is now widely cultivated, all over the world.
Wheat has a higher protein content, compared to other cereals,
like rice and corn.
Wheat was the first cereal, which was cultivated on a large scale.
It was the key to emergence of city based civilisation.
Wheat was amenable to long term storage.
Wheat contributed to the emergence of the first city-states.
Wheat is processed by milling.
The outer husk is removed.
The wheat grain is broken into smaller parts.
Wheat is often ground, into a powder form.
This is called as wheat flour.
There are generally 3 types of wheat flour.
White flour is made from the endosperm only.
Brown flour includes some of the germ and bran.
Wholemeal flour is made from the entire grain,
the endosperm, the germ and the bran.
The endosperm contains mostly carbohydrates, in the form of starch.
The germ contains protein, fats and vitamins.
Bran contains dietary fibre.
Whole meal flour is very nutrient rich, and healthy.
Maida is finely milled and refined wheat flour.
It is also bleached using chemicals, to give it a white color.
This kind of flour is very popular.
It is used to make bread, and Indian breads like paratha, naan,
kulcha and rumali roti.
World wide it is used to make pizza, pancakes,
pies, pastries, cakes, cookies, biscuits etc.
From a nutrition view point, less refined grain and flour, is more healthier,
than refined grain and flour.
100 grams of wheat typically provides:
327 kilo calories, or 327 food calories of energy.
Carbohydrates: 71 grams.
Protein: 13 grams.
Fat: 1.5 grams.
Dietary fibre: 12 grams.
Wheat also has minerals like,
Calcium.
Magnesium.
Phosphorous,
Potassium, etc.
Wheat also has vitamins like,
Thiamine or vitamin B1.
Riboflavin or vitamin B2.
Niacin or vitamin B3.
and vitamin B5 and B6, etc.
Rice.
Rice is the most consumed staple food, specially in Asia.
Though rice had its origin in Asia, it is now cultivated, in many parts of the world.
Rice cultivation is water and labour intensive.
The seeds of the rice plant is milled, and the outer husk is removed.
At this point in the process, it is called as brown rice.
If the milling is continued, to remove the germ and the husk,
it is called as white rice.
White rice can be stored for a longer period of time.
Sometimes white rice is polished with glucose or talc powder.
This gives it a more attractive shiny appearance.
Brown rice is whole grain rice.
It has a mild, nutty flavour, and is chewier.
From the nutrient view point, brown rice is healthier,
than polished rice.
Rice can be made into a porridge, also called as congee.
Some people eat it as breakfast food.
Rice porridge is also a traditional food, for people who are unwell.
100 grams of rice typically provides:
365 kilo calories, or 365 food calories of energy.
Carbohydrates: 80 grams.
Protein: 7 grams.
Fat: .7 gram.
Dietary fibre: 1.3 grams.
Rice also has minerals like:
Calcium.
Magnesium.
Phosphorous.
Potassium, etc.
Rice also has vitamins like:
Thiamine or vitamin B1.
Riboflavin or vitamin B2.
Niacin or vitamin B3.
and vitamin B5 and B6, etc.
Over half the world’s population eat rice as a staple food.
Maize.
Maize is also called as corn.
It was originally cultivated in Mesoamerica.
The leafy stalk produces the grain, which are seeds called kernels.
Maize is often used in cooking, as a starch.
Maize or corn is the most widely grown grain, specially in the USA.
We are familiar with it as a food in the form of corn flour,
corn flakes and popcorn.
Most of the corn produced, is used as animal feed.
Some of it, is also used to produce ethanol.
Ethanol is used as a bio fuel.
It is mixed with petrol, and used as a fuel.
Grain legumes or pulses.
A legume is a fruit or seed of a plant.
It is also called as a pulse or dal.
Dal is a good source of protein.
There are many types of dal.
Some commonly used dal are:
Toor dal, also called as yellow pigeon pea.
Channa dal, also called as chickpeas, or bengal gram.
Moong dal, also called as mung beans.
Urad dal, also called as black gram.
Some other common legumes are:
Soya bean.
Peas.
Peanuts, etc.
Pulses have a high proportion of proteins.
Typically 20 to 25% of a pulse, is protein.
Pulses thus become an important part of a balanced diet.
Cereals have a higher proportion of carbohydrates.
Pulses have a higher proportion of proteins.
A typical Indian meal will comprise of:
Rice and dal.
Or wheat bread and dal.
This combination provides carbohydrates and proteins,
required for a balanced diet.
100 grams of pulses typically provides:
350 kcal or 350 food calories, of energy.
Carbohydrates: 80 grams.
Protein: 26 grams.
Fat: 1 gram.
Pulses also contain minerals like:
Calcium.
Magnesium.
Phosphorous.
Potassium, etc..
Pulses also has vitamins like:
Thiamine or vitamin B1.
Riboflavin or vitamin B2.
Niacin or vitamin B3.
vitamin B5 and B6.
and vitamin C etc..
Vegetable oil.
Vegetable oils are commonly used for cooking.
They are used for frying, baking, and other types of cooking.
It is also sometime used as a dressing for salads, etc.
Vegetable oil contains triglycerides, or fats.
Vegetable oils are extracted from oil seeds.
Some examples of vegetable oils are:
Groundnut or peanut oil.
Sunflower oil.
Coconut oil.
Rice bran oil.
Olive oil.
Soya bean oil, etc.
Sesame oil.
Palm oil.
Corn oil.
When oil is heated, it starts smoking at some point.
This is called as the smoke point, of the oil.
The ingredients oil starts decomposing and degrading.
Each vegetable oil has a specific smoke point.
When we need to do cooking at higher temperatures,
it is better to use an oil with a higher smoke point.
Oils contain saturated fats, poly unsaturated fats, and mono unsaturated fats.
Unsaturated fats are considered more healthy, than saturated fats.
Nutrition experts recommend lower consumption of saturated fats.
Groundnut or peanut oil.
100 grams of peanut oil has:
17 grams of saturated fat.
46 grams of monounsaturated fat.
32 grams of polyunsaturated fat.
It has a smoking point of 225 degrees centigrade.
Sunflower oil.
100 grams of sunflower oil has:
11 grams of saturated fat.
20 grams of monounsaturated fat.
69 grams of polyunsaturated fat.
It has a smoking point of 225 degrees centigrade.
Coconut oil.
100 grams of coconut oil has:
86 grams of saturated fat.
6 grams of monounsaturated fat.
2 grams of polyunsaturated fat.
It has a smoking point of 177 degrees centigrade.
Rice bran oil.
100 grams of rice bran oil has:
25 grams of saturated fat.
38 grams of monounsaturated fat.
37 grams of polyunsaturated fat.
It has a smoking point of 250 degrees centigrade.
Olive oil.
100 grams of olive oil has:
14 grams of saturated fat.
73 grams of monounsaturated fat.
11 grams of polyunsaturated fat.
It has a low smoking point of 180 degrees centigrade.
The same oil can come in different varieties.
The contents of an oil, that we discussed, are only typical examples.
It is advisable to check the food label, to determine the actual contents.
Trans fat, is a type of unsaturated fat.
It is uncommon in nature.
Industrially produced vegetable oils are hydrogenated to produce saturated fats.
This process leads to partial conversion of unsaturated fats,
to trans fat.
Hydrogenated oils are more convenient for storage and transportation,
because it has a melting point of 30 to 40 degrees centigrade.
Hydrogenated oil is used in snack food, packaged baked foods,
fast foods, sweets etc.
Trans fats are edible.
Consumption of trans fats are shown to increase risks,
of coronary heart disease.
It raises the level of low density lipoprotein, or LDL.
LDL is known as bad cholesterol.
Trans fats reduce the level of high density lipoprotein, or HDL.
HDL is known as good cholesterol.
It would be a healthy practice, to reduce, or eliminate trans fats, in our food.
Vegetables.
The use of cultivated vegetables, started around 10000 BC.
Even when we were hunter gatherers, we used to seek out,
gather, cook and eat wild vegetables for food.
Later, we learnt to cultivate them, and grow a variety,
of quality vegetables.
Cultivated varieties of plants, are called cultivars.
Cultivar is a combination word of cultivated and variety.
There are hundreds of cultivar vegetables available today.
Botanically, any part of a plant, is a vegetable.
It could be the leaves, the stem, the bud, the flower, the fruit,
the tubers, the bulbs, the corns, the root or the seed.
For our discussion, we will use the culinary definition of vegetables.
Vegetables are normally cooked, and various delicious dishes,
are prepared using this.
These dishes can vary from country to country, and region to region.
Each dish has it’s unique taste and flavour.
Salads can also be prepared using raw vegetables.
Cereals and pulses, can be stored for a long period of time,
for months and even years.
Vegetables cannot be stored, for such a long period.
Vegetables are normally consumed when fresh.
Refrigeration or deep freezing, can extend the storage period,
to a limited extent.
Vegetables have a small component of carbohydrates, very little protein,
and almost no fat.
They contain a generous amount of dietary fibre, which is essential,
for good digestion of food.
Vegetables have very few calories.
Vegetables are rich in minerals and vitamins.
Most of the essential minerals and vitamins, for our body,
are contained in vegetables.
For a healthy life style, it is recommended, to have a significant proportion,
of vegetables in our diet.
It is also desirable to have a variety of vegetables, in our diet.
The variety helps in providing a larger range of essential minerals and vitamins.
Needless to say, they also provide a variety of taste and flavour.
We will discuss some common categories of vegetables that we use for food.
Bulb vegetables.
A bulb is a short stem of a plant, which acts as a food storage organ,
of the plant.
Some examples of bulb vegetables are:
Onion.
Garlic.
These type of vegetables, can be stored for a slightly longer period of time.
Some of them have medicinal properties.
Fruit vegetable.
Some vegetables are botanically fruits, but are used as vegetables,
in the culinary sense.
Some examples of fruit vegetables are:
Cucumbers.
Tomatoes.
Brinjals.
Capsicum.
Pumpkin.
Inflorescent vegetables.
Inflorescent vegetables are clusters of flowers arranged in a stem.
They can be a nutritious food.
Some examples of inflorescent vegetables are:
Cauliflower.
Banana flower.
Leaf vegetables.
Many plants have leaves, which serves as a tasty nutritious vegetable.
They are called leaf vegetables.
They are very nutritious.
They have disease fighting phytochemicals and fibre.
They are very useful for weight loss programs.
Leafy vegetables help in reducing cholesterol and blood pressure.
Some examples of leaf vegetables are:
Cabbage.
Spinach.
Lettuce.
Root vegetables.
Some plants store their nutrition in the roots.
These roots are a good source of vegetable food.
Many of them contain carbohydrates in the form of starch.
Some examples of root vegetables are:
Carrots.
Radish.
Turnips.
Stalk vegetables.
The stalk of some plants, can be used as a vegetable.
Some examples of stalk vegetables are:
Asparagus.
Celery.
Bamboo.
Tuber vegetables.
Some plants store their nutrients in tubers.
These tubers can be good vegetables.
Some examples of tuber vegetables are:
Potatoes.
Cassava.
Sweet potato.
Yam.
Pods.
Some types of legumes, are also called as pods.
Some examples of pods are:
Beans.
Broad beans.
Peas.
Vegetables need to be cooked appropriately,
to retain all the nutrients.
Over cooking vegetables could result, in loss of nutrients.
Each vegetable has it’s own unique taste and flavour.
By light cooking, like steaming, we can not only enjoy the unique taste,
we can also retain all the nutrients.
Over time thousands of recipes, have been formulated,
to cook a variety of delicious dishes.
We need to plan our diet in such a way,
so as to include a healthy proportion of vegetables.
Fruits.
Fruits are the means by which plants disseminate seeds.
Fruits usually develop from the flowers of flowering plants and trees.
It is as if nature deliberately designed fruits to have a delicious taste.
The taste of fruits, induces animals, including human beings,
to eat the fruit and disseminate the seeds.
Our ancestors probably sought out and ate fruits,
even before they ate vegetables.
Fruits have the added advantage, that they can be consumed,
without cooking.
We will use the term fruits, in the culinary sense, in our discussion.
Fruits have a low carbohydrate, and almost no protein and fat content.
Fruits are rich in fibre, sugars and vitamins.
The three most common type of fruits are,
Drupes.
Berries.
Pome.
Fruits typically have seeds, which are covered with a middle and outer layer.
The outer layer is called as the exocarp.
The middle layer is called as the mesocarp.
The inner layer is called as the endocarp.
Fruits start as a flower, and then develop into a fruit.
A fruit goes through a ripening process, before it is ready to eat it.
Drupes.
Drupes are fleshy fruits, that contain a single seed.
The seed is surrounded by a hard shell, called as the endocarp.
It has a outer skin called the exocarp.
It has a fleshy part, called as the mesocarp.
Some examples of drupe type of fruits are:
Mango.
Olive.
Dates.
Apricot.
Cherry.
Peach.
Plum.
Sapote.
The fleshy part of drupes, are delicious, and ready to eat.
Berry.
A berry is a fleshy fruit, produced from a single flower,
containing one ovary.
The entire ovary wall develops into a edible pericarp.
The seeds are usually embedded in the fleshy pericarp.
Some examples of berry type of fruits are:
Avocado.
Banana.
Blueberry.
Cranberry.
Gooseberry.
Grapes.
Strawberry.
Orange.
Pome.
Pomes are another type of common fruit.
Some examples of pome type of fruits are:
Apple.
Pear.
Fruits are very good for health.
They are rich in vitamins, minerals, and other essential nutrients.
They help to develop the immune system,
and protect us from many diseases.
Fruits have antioxidants.
Fruits help to reduce blood pressure.
Fruits have low calorie content, and help to maintain healthy weight.
They have natural sugars, which provide energy.
They help to maintain a healthy skin tone.
Of course fruits taste delicious.
Nutrition experts recommend to include a healthy proportion,
of fruits in our daily diet.
Nuts.
We will use the term, nut, in the culinary sense.
Any large kernel inside a shell, used in food, is commonly called as a nut.
Nuts are an important source of nutrition for wild life.
Nuts are a healthy source of nutrition, for human beings.
Nuts have a high calorie content.
They are a good source for energy.
Nuts have proteins.
Nuts have essential monounsaturated and polyunsaturated fats,
which are good for health.
They are rich in essential vitamins and minerals.
Typical minerals contained in nuts are magnesium, phosphorus,
potassium, copper, and selenium.
Nuts can be broadly classified as:
Botanical nuts.
These are dry hard shelled, uncompartmented fruit,
which do not split on maturity, to release seeds.
For example, chestnuts and hazelnuts.
Drupes.
These are fleshy fruits, surrounding a stone or pit, containing a seed.
For example, almonds.
Gymnosperm.
These are naked seeds, with no enclosure.
For example, pine nuts.
Angiosperm.
These are seeds, with in a larger fruit.
For example, peanuts.
The nutrition content of some representative nuts are:
Almonds.
Proteins : 21% .
Carbohydrates : 28%
Polyunsaturated fat : 12%.
Monounsaturated fat : 32%.
Saturated fat : 4%.
Walnuts.
Proteins : 15% .
Carbohydrates : 20%
Polyunsaturated fat : 47%.
Monounsaturated fat : 9%.
Saturated fat : 7%.
Peanuts.
Proteins : 24% .
Carbohydrates : 27%
Polyunsaturated fat : 16%.
Monounsaturated fat : 25%.
Saturated fat : 7%.
Pistachio.
Proteins : 21% .
Carbohydrates : 35%
Polyunsaturated fat : 13%.
Monounsaturated fat : 23%.
Saturated fat : 6%.
It would be a healthy practice, to include nuts, in our diet.
Herbs and spices.
In general herbs and spices are used for flavouring,
and adding fragrance to food.
They also have medicinal value.
Sometimes herbs refer to the leafy green parts of the plant,
and spices refer to the dried part of the plants.
Use of herbs and spices, have a long history,
going back many thousands of years.
India was once very famous for it’s spice trade.
There are hundreds of herbs and spices, which are used in cooking.
Some of them, are unique to certain cultures.
We will discuss a few representative herbs and spices.
Basil.
Basil or tulsi, is widely used in the Indian sub continent.
It is believed to have medicinal properties.
Bay leaf.
It is an aromatic leaf, used for culinary and medicinal purposes.
Garlic.
Garlic has been in use, more than 7000 years.
It was used in early Egyptian civilisation.
It is used for culinary and medicinal purposes.
Some other examples of culinary herbs and spices are:
Coriander.
Curry leaf.
Lemon grass.
Mint.
Parsley.
Ginger.
Onion.
Cardamom.
Cinnamon.
Star anise.
Nutmeg.
Saffron.
Cloves.
Mustard.
Cumin.
Fenugreek.
Turmeric.
Pepper.
Food preservation.
Food like vegetables and fruits, tend to decompose.
Bacteria, moisture and oxygen, contribute to decomposition of food.
Different techniques are used to preserve food, for a longer period of time.
Preservation of food extends it’s life period, and increases it’s usefulness.
We will discuss a few of these techniques, for food preservation.
Drying.
Drying is one of the oldest methods, used for food preservation.
Drying removes the moisture content from the food.
Some foods can be preserved longer, by drying.
Raisin, apricots, are some examples of dried food.
Pickling.
Pickling was one more method for preserving food.
Typically pickling involves placing the food in a liquid,
which inhibits or kills microorganisms.
Brine or salt solution, is one commonly used preservative.
Vinegar, and vegetable oil, are also used as preservatives.
Artificial food additives.
Some artificial additives, are used to preserve food.
Some of the additives are, anti microbial, which inhibits the growth of bacteria.
Some of them are antioxidants, which inhibit the oxidation of food.
Some anti microbial preservatives are calcium propionate,
sodium nitrate, sulphur dioxide, sodium bisulfate, etc.
BHA and BHT, are some antioxidants which are used.
The type and amount of additives used, are regulated by government authorities.
Some people prefer food with little or no artificial additives, for health reasons.
Lactic acid bacteria, or L A B, is an anti microbial additive,
which is used as a bio preservative.
Packaged food.
Food can be packaged, in a special way, to increase it’s shelf life.
The shelf life of food, indicates how long it can be kept, without spoiling.
Packaged food, will typically have a label, containing the expiry date.
This indicates how long the food can be kept, without spoiling.
Various techniques are used, to package food, to increase it’s shelf life.
Some of the techniques are :
Canning.
Bottling.
Vacuum packing.
Aseptic packing.
Canning and bottling involves cooking food, and storing it in sterile containers.
Usually, the product and the package, are combined and then sterilised.
In vacuum packing, the air is removed, a vacuum created,
and the food is packed in an air tight container.
The vacuum strips bacteria of oxygen, which it needs for survival.
Aseptic packing also uses the sterilisation concept.
In aseptic packing, the product and the packing, are sterilised independently,
and then combined and sealed in a sterile atmosphere.
The food is sterilised by ultra heat treatment.
Aseptic packing, like tetra pack, can preserve food for several months.
With agriculture being industrialised, the use of packaged food,
is becoming increasingly used.
Refrigeration.
Storing food, in a cool atmosphere, increases it’s shelf life.
Cooling slows down, the decomposition of food.
Food stored in domestic refrigerators, stays longer, without spoiling.
This method is now widely used, using domestic refrigerators.
Freezing.
Industrial freezing, is now widely used for preserving food.
Two common methods used are :
Mechanical freezing.
Cryogenic or flash freezing.
Mechanical freezing.
Mechanical freezing is achieved by cooling the food, to about -10 degree Celsius.
At temperatures below the freezing point of water, the moisture in the food,
turns to ice.
Under these conditions the growth of micro organisms, is inhibited.
Mechanical freezing can be achieved, with domestic freezers.
Slow freezing results in formation of larger ice crystals,
which can cause some degradation in the food.
This maybe the reason, some people complain, of the loss of flavour,
in frozen food.
Cryogenic freezing.
In cryogenic freezing, the food is cooled to much lower temperatures,
like, minus 196 degree celsius.
In this process the cooling is effected, very rapidly.
That is why it is called as flash freezing.
Flash freezing dramatically changes, the way in which ice crystals, are formed.
Much smaller ice crystals are formed, in this process.
These minute crystals, do not damage the tissue of the food.
This results in retaining the flavour and texture, of the food.
Flash frozen food, also have an extended shelf life.
This method is now widely used, in preserving food.
India is the second largest producer of vegetables and fruits.
About 18% of this food, is wasted, due to lack of proper cold storage facilities.
Increased urbanisation is becoming inevitable, in the foreseeable future.
Given this fact, the production of food like vegetables and fruits,
is bound to be at a large distance, from the urban consuming areas.
This provides a compelling reason, to create a cold chain facility,
from the place of production, to the place of consumption.
Efficient food storage, packaging and transportation,
is as important as food production, for a increasingly urbanised population.