TOPIC TWO
NUTRITION
Concepts of Nutrition and food
Nutrients
INTRODUCTION
Meaning of nutrition
Nutrition is the process by which
organisms take in and use nutrients.
Nutrients are any substances that
nourish an organism.
Food is
any material when taken in absorbed and utilized meet requirement of plant and
animal body.
Explain the concepts of nutrition
and food nutrients FUNCTION OF FOOD
1. Oxidized
to release energy
2. Used in
growth of cells
3. Used to
repair lost cells and tissue
TYPES OF NUTRITION
There are
two main types of nutrition: autotrophic nutrition and heterotrophic nutrition.
Autotrophic Nutrition
Is the process by which organisms manufacture their
own food from simple inorganic substances like carbon and hydrogen using either
light energy(photosynthesis) or chemical energy (chemosynthesis)
Heterotrophic Nutrition
Is the
process in which organisms get nutrients by eating other organisms
IMPORTANCE OF NUTRITION
1. Prevent
diseases
2. Helps
growth and development of cells, tissue and organs
3. It helps to
repair damaged parts
4. It helps
to protect the body against infection and diseases
Nutrition
in Mammals, Human Nutrition
Human Nutrition is the provision to obtain the essential nutrients necessary to support
life and health.
OR
Are several types of food substances that are needed by the human body
for its proper functioning.
The basic food substances include proteins, carbohydrates, lipids,
vitamins, minerals, roughage and water.
Different
Types of Food Substances and their Functions in Human Body
Identify different types of food substances and
their functions in human Body
PROTEINS
These are
substances, which contain elements oxygen and nitrogen.
SOURCE OF PROTEINS
Foods such as Meat, liver, eggs, beans, milk, cheese, peas, groundnuts
and mushrooms are good sources of protein.
FUNCTION OF PROTEINS
The
following are the function of protein
1. It is
used in body building
2. Used by
body for tissue growth and repair such as healing of wounds and replacement of
skin
3. Used as a
source of energy, especially when the body lacks carbohydrates and lipids
4. It
enables red blood cells to transport oxygen in our bodies
CARBOHYDRATES
Carbohydrates
are mainly made of carbon, hydrogen and oxygen
Foods such as maize, rice, bananas, potatoes, cassava, wheat (bread,
cake) and yams are rich in carbohydrates.
FUNCTIONS OF CARBOHYDRATES
The
following are the function of carbohydrates
1. They are
chief source of energy
2. In plants
they are stored as starch
3. In
animals they are stored as glycogen
LIPIDS
These are compounds of carbon, hydrogen and oxygen. They are insoluble
in water. Lipids are made up of fatty acid and glycogen
SOURCES OF LIPIDS
Foods
such as fish, nuts, seed oils, avocados and olives are good sources of lipids.
FUNCTIONS OF LIPIDS
1. Lipids
are used as a source of energy
2. Protect
the organs such as heart and kidneys
VITAMINS
Vitamins are chemical substances in small amounts that are used to
maintain the body. Vitamins can be grouped into two categories: water-soluble
and fat-soluble vitamins.
Fat-Soluble Vitamins can be stored in the body. Examples of fat-soluble vitamins are Vitamins A, O, E and K
Water-Soluble Vitamins are not stored in the body. Vitamins B and C are water soluble.Vitamin B is of various forms,
namely Vitamin B1, B2, B6 and B12.
SOURCES, FUNCTIONS AND SIGNS OF
VITAMIN DEFICIENCIES
VITAMIN SOURCE FUNCTION
Essential
for the formation of
Liver, Milk Carrots,Orange and Yellow
Vitamin A(Retinol) membranes
of the eyes and Vegetables
the
respiratory tract
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Lean
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Carbohydrates
metabolism of
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meat,liver,
eggs,tomatoes,yeast
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Vitamin B1(Thiamine)
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all foods and release of energy
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extract sand brown rice
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to cells
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Needed
for metabolism of all
Liver,meat,wholegrain,cereals,yeast
Vitamin
B2(Riboflavin) foods and release energy to
extracts
cells
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Vitamin
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Meat,vegetables,yeast
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extracts,whole
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Essential
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in
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protein
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B6(Pyridoxine)
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grain
cereals
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metabolism
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Vitamin
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Fish,
meat,eggs, milk and liver
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Builds
genetic materials, help
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B12(Cyanocobalamin)
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to form
red blood cells
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-
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Increaseresistant
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to
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Vitamin
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C(Ascorbic
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Pawpaw,Citrus
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fruits,Fresh
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diseases.-
Improve absorption
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of
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iron.-
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Used insynthesis
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Acid)
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Green,vegetables,tomatoes
and potatoes
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ofcollagen
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in
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thebones
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and
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gums
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SIGN OF DEFICIENCY
- Night blindness-Increased risk of infections
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Beriberi- Loss of Appetite -
Muscle cramps- Heart failure
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Cracks and sores around the mouth
and
nose- Visual problems
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Nerve irritability-Sores in the
mouth and eyes- Anaemia
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Anaemia- Nerve damage- Weight
Loss
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Helps to
build and maintain
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Rickets in children-
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Vitamin
D(Calciterol)
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Osteoporosis
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(soft
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Egg yolk,milk, oilfish andliver
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teeth and bones
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bones)
in adults
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-
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Antioxidant-
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Nerve
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Vitamin
E(Tocopherol)
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Sunflower oil, butter,brown rice
and
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of
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abnormalities-
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Preventsdamage
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peanuts
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Infertility
in rats
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cellmembrane
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Needed
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for
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normalblood
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Defective
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blood
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Vitamin
K
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coagulation
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resulting
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Green vegetables and liver
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clotting
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in
excessive bleeding.
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MINERALS
Certain mineral elements are vital for the proper
functioning of the body. Some are required in relatively large quantities and
therefore called macro mineral sand others are required in very small
quantities and are referred to as micro
Macro minerals include calcium, phosphates, potassium, iron, zinc, sodiumchlorine and magnesium.
Micro minerals include
iodine, fluoride, manganese and copper.
Examples
of minerals, their source and their function in the body
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MINERAL
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SOURCE
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FUNCTION
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SIGN OF
DEFICIENCY
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Calcium
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Milk,Cheese,eggsandgreen
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- Helps
build strong bones and teeth-
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- Weak
bones- Bleeding easily
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vegetables
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Important
in clotting of blood
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Phosphates
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Meat,
Milk,Fish, Eggs and nuts
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- Builds
bones and teeth-
Helps in
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- Poor bone and teeth formation
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muscle
and nerve activity
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Potassium
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Peanuts,bananas,orange
juice and
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Needed
for nerve and muscle function
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- Poor
muscle contraction
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green
beans
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Iron
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Liver,kidney,beans
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and
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green
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Essential
for making hemoglobin
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-
Anemia
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vegetables
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Zinc
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Meat,
yeast
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Helps
to heal wounds
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- Skin
problems
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Sodium
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Table
salt
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- For
nerve and muscle activity
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Muscle cramps
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Chlorine
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Table
salt
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Formation
of hydrochloric acid in the
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- Poor
digestion of protein
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stomach
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Magnesium
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Spinach,pumpkin
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seeds,
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black
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- Relaxation
of nerves and
muscles-
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Muscle
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weakness-
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Irregular
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beans
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Strengthening
of bones
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heartbeat-
Weak bones
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Copper
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Meat,
fish and liver
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Activation
of enzyme
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Anemia-
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Bone and joint
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problems
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Manganese
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Kidneys,liver,
tea,coffee, nuts and
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Formation
of bones
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Nausea-
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Dizziness-
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Loss of
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fruits
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hearing
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Iodine
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Iodized
table salt and sea food
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Production
of thyroid hormones which
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Goitre (enlarged thyroid gland)
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regulate
growth
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ROUGHAGE
This is
dietary fiber that is obtained from the indigestible parts of plants.
SOURCES OF ROUGHAGE
Foods such as fruits, beans, cabbage, spinach, cassava, and whole baked
potatoes are good sources of roughage.
FUNCTIONS OF ROUGHAGE
It helps
in the passage of food and feces through the gut by aiding contraction of the
gut muscles
WATER
SOURCES OF WATER
Rainfall,
Rivers, Springs etc.
FUNCTIONS OF WATER
1. Used in
digestion of food
2. Used in
transport of material in the body
3. Used as
solvent in chemical reaction
The
Concept of Balanced Diet in Terms of Food Quality and Quantity
Explain the concept of balanced diet in terms of
food quality and quantity
A BALANCED DIET
A balanced diet refers to food containing all types
of food nutrients in the correct proportions. We should eat a diet low in fats,
sugars and salts but high in protein, carbohydrates, vitamins, minerals and
roughage. More importantly we should take in large amounts of water.
IMPORTANCE OF A BALANCED DIET
In order for the body to function properly,
different food substances are required to do different works for example:
1. Carbohydrates
provide energy
2. Vitamins
needed to keep the body healthy
3. Minerals
are needed for protection against diseases
4. Water is
a universal solvent
Nutritional
Requirement for Different Groups of People
Explain nutritional requirement for different
groups of people
The
following are nutritional requirements:
a. Expectants:
There diet should contain more protein and minerals (Calcium (Ca) and Iron
(Fe))
b.
Lactating Mothers: Their
requirements are like those of expectant but in greater amount to feed the body
c. Children:
Require a lot of proteins for growth and development of body tissue.
d.
The elderly People: They require
adequate amounts of vitamins and minerals to maintain their health
e.
Sedentary workers: These are
individuals who stay in one place for along time while performing their daily
occupational activities. Due to their lifestyle and occupation,obesity is increasingly
common among them, they limit their intake of food rich in lipids.
f.
Sick people: They need special
and plenty of nutrients to help recover their health, those who have incurable
diseases such as HIV/AIDS should get food that will help them to manage their
conditions. They need to take plenty of fruits and water.
Different
Types of Nutritional Deficiencies and Disorders in Human Beings
Outline different types of nutritional deficiencies
and disorders in human beings
MALNUTRITION
This is the condition, which occurs when one fails
to feed on a balanced diet. It may be too little or eating only one type. These
deficiencies and disorders include obesity, rickets, kwashiorkor, marasmus and
anorexia nervosa.
Nutritional Disorders
These are
conditions of ill health in a person, which arise as a result of lifestyle.
The Causes, Symptoms, Effect and Control Measures of Nutritional
Deficiencies and Disorders
Explain the causes , symptoms,
effect and control measures of nutritional deficiencies and disorders
Causes of Malnutrition
There
three cause of mulnutrition
1. Eating
too little
2. Eating
too much
3. Eating
one type of food
Effects of Malnutrition
1. Excessive
feeding causes obesity
2. Under
nutrition causes deficiency diseases
CAUSE, SYMPTOMS AND PREVENTION OF NUTRITIONAL DEFICIENCIES AND DISORDERS
IN HUMAN BEINGS
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DISEASE
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CAUSES
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EFFECTS
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SYMPTOMS
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PREVENTION
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- Poor
growth- Diarrhea-
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Loss of
appetite- Pale skin-
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Consumption
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Shortage of
protein in
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Dry skin-
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Kwashiorkor
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Change colour
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in
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diet
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offoodsrich
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and texture- Body becomes
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weak
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and
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protein
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stomach
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protrudes
- Lack of
and equate
amountoffood-
Marasmus
Ignorance of balanced diet preparation of food,
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Weight loss- Slowed growth-Decrease
dactivity-Lac k of energy - Shrunk enbuttocks
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Getting adequate amounts of food
- Balanced diet
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food
hygiene
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Lack
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of
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- Bow
legs- Knock
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- Provide
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food rich
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vitamin
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An
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odd
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with
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vitamin
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Rickets
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D,Phosphates
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knees-
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and
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skul-
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D,Phosphates
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and
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Calcium
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shaped
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Deformed
spine
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Calcium
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- Pain
in joints-
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Provide
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diet
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which
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Scurvy
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Lack of
vitamin C
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Stunted
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growth-
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containsfruits-
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Avoid
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Bleed
in gums
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prolonged
cooking
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Goitre
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Lack of
iodine
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- Swelling
of
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the
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Provide iodized salt
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thyroid
gland
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and
water(H2O)
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Digestive
System in Human
DIGESTIVE
SYSTEM IN HUMAN BEINGS
The digestive system of human refers to the human alimentary canal and
the organs and glands associated with it.
Parts of
the Human Digestive System and their Adaptive Features
Identify parts of the human digestive System and
their adaptive features
THE MAIN PARTS OF ALIMENTARY CANAL
The main parts are:- Mouth, Oesophagus, stomach, small intestine,
(duodenum and ileum), large intestine (colon) and rectum.
ADAPTATIONS OF STOMACH TO ITS
MODE OF FUNCTION
1. Stomach
has sphincter muscles to prevent food from flowing back into the oesophagus
2. Stomach
has gastric glands, which produce gastric juice for the digestive process.
3. Also in
the stomach of a young baby there is renin which coagulates milk
5. There is
hydrochloric acid for the emulsification of fats and killing of bacteria
ADAPTATIONS
OF ILLEUM TO ITS FUNCTIONS
The
following are the adaptations of ileum to its mode of functions:-
1. It has
secretory glands, which produce digestive enzymes
2. It is
connected to the liver by the bile duct which enable the bile to reach ileum
3. It has
finger like projections called villi for the absorption of food
4. The ileum
is very long to ensure sufficient absorptions of food
5.
The villi have large network of
blood capillaries for transporting absorbed food to all parts of the body
6. The inner
lining of the ileum is folded to increase the surface area for absorption
The
Digestion Process in Human Being
DIGESTION PROCESS IN HUMAN BEINGS
Digestion is the process by which food is broken
down into a form that can be absorbed and used by the body.
Digestion process involves two processes, which are
mechanical break down of food and chemical break down of food. The mechanical
break down of food takes place in the mouth where the food is chewed by teeth
so as to reduce it into small pieces.
Digestive enzymes achieve chemical break down of
food. The digested food is absorbed and assimilated in the body.
The digestion process starts in the mouth where
food is mechanically broken down by teeth. The presence of food in the mouth
stimulates the salivary gland to produce more saliva.
1. Have
salivary amylase enzyme that converts starch into maltose
2. To
moisten the food
3. To
provide medium for enzyme reactions
4. Have
mucus to lubricate food for easy swallowing
5. Saliva
consists of Sodium and Calcium salt to ensure alkaline medium for amylase
enzyme
Difference Between the Human Digestive System with that of Other Mammals
The
ruminants‟ digestive system differs from human digestive system in the following
ways:
·
Ruminants have more elaborate system to enable
cellulose digestion
·
The stomach of ruminants have four chambers (rumen,
reticulum,omasum, abomasum)
·
The food is regurgitated, chewed, and again then
passed to omasum.
Common
Disorders and Diseases of the Human Digestive System
DISORDERS AND DISEASE OF THE DIGESTIVE SYSTEM
These include diseases and disorders that affect teeth, oesophagus,
stomach, small intestine and large intestines
Examples
are:- dental caries, heart burn, ulcers, constipation and flatulence.
1.
Dental caries This is commonly referred to as
tooth decay. It occurs when bacteria destroy the outer part of the tooth.
2.
Heart burn Refers to the burning or painful
sensation in the oesophagus. It is caused by regurgitation of hydrochloric acid in the stomach which leads to
the irritation of oesophagus.
3.
Stomach ulcers Refers to the sore in stomach
lining. It is caused by erosion of stomach wall due to enzyme reactions.
4.
Constipation Refers to the decrease in
frequency of formation of stool. It occurs when the stool becomes dry and hard due to excessive water absorption in the
colon.
5. FlatulenceThis is caused by excess gas in
the digestive tract
Causes, Symptoms, Effects and Control Measures of Common Disorders and
Diseases of the Human Digestive System
Explain causes, symptoms, effects
and control measures of common disorders and diseases of the human digestive
system
SYMPTOMS OF DENTAL CARIES
1. Tooth
ache
2. Holes in
the teeth
CONTROL MEASURES TO CARIES
1. Regular
brushing of teeth
2. Damaged
teeth can be filled with artificial crown
3. Minimization
of intake of foods rich in sugar
4. Avoid
eating very hot or cold foods
5. Have
regular dental check ups
SYMPTOMS OF STOMACH ULCERS
1. Burning
pain in the stomach
2. Nausea
and vomiting
4. Blood in
vomit or stool
CONTROL MEASURES TO STOMACH ULCERS
1. Medication
2. Avoid
smoking
3. Avoid
taking alcohol
4. Avoid
eating acidic foods
SYMPTOMS OF CONSTIPATION
1. Lack of
bowel movements for two or three days
2. Hard
stools
3. The urge
to go for long call even after you have just been to the toilet
PREVENTION OF CONSTIPATION
1. Eat
enough fibre
2. Drink
enough water
3. Exercise
regularly
4. Seek
medical help
CAUSES OF FLATULENCE
1. Swallowed
air
2. Eating
food that causes gas such as beans, cabbage, milk and onions
3. Poor
absorptions of carbohydrates
SYMPTOMS OF FLATULENCE
2. The
constant urge to pass wind
3. Excessive
belching
4. Accumulation
of gas in the stomach
PREVENTION OF FLATULENCE
1. Avoid
foods that produce gas
2. Chewing
food properly
3. Limit the
amount of food which are
Nutrition in Plant, Mineral requirement in Plants Essential Mineral
Element in Plant Nutrition
Mention essential mineral element in plant
nutrition
The
mineral requirement in plant growth are categorized into two groups:
1. Micro
nutrients or minerals
2. Macro
nutrients
Macro
nutrients are minerals that are required in a large quantity for the plant
growth.
They include; Nitrogen, phosphorus, potassium, sulphur, sodium,
magnesium, carbon, hydrogen,and oxygen.
element Role
Protein
synthesis Manufacture of chlorophyll Promotes
nitrogen
normal plant growth
Deficiency
Leaves
become pale green, yellow, small leaves, thin weak stem and stunted growth
phosphorus Promote
root and branch growth Protein synthesis and Poor growth
of roots, leaves
and branches Leaves
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energy
release in respiration
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Potassium
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Used
during photosynthesis and protein metabolism in
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younger
lieves
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Calcium
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Promotes
normal plant growth and cell wall formation
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Magnesium
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Manufacture
chlorophyll
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Sulphur
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Protein
synthesis
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become reddish purple
Yellow
leaves with dead spots especially at margins and tips
Poor root growth Death of growing
regions
Yellowing of leaves
Stunted growth Yellow patchers on
leaves
Micro
nutrients; these are nutrients that are required in small amount for the plant
growth.
They
include; iron, cobalt, fluoride, silicon, iodine, copper and zink
The
Concept of Photosynthesis
Photosynthesis is the process where by green plants
manufacture their own food by using light energy produced from the sun.
Photosynthesis takes place in plants especially in leaves so as to make their
own food by the presence of different factors.
FACTORS FOR PHOTOSYNTHESIS
Chlorophyll, carbondioxide, sunlight energy,
mineral salts, temperature and water. Equation for photosynthesis:
The
Structure of the Leaf in Relation to Photosynthesis
Describe the structure of the leaf in relation to
photosynthesis
The petiole or leaf stalk attaches the leaf to the
branch or stem. It keeps the lamina in position that will enable it to get a
maximum amount of sunlight. The lamina has a large surface area, thus maximizes
the absorption of light energy and carbondioxide. The lamina is also thin so
that carbondioxide and light energy diffuse over a shot distance to reach
cells.
The mid rib and veins contain xylem and phloem.
Xylem vessels transport water and mineral salt to the leaf. Phloem vessels
transport manufactured food to other parts of the plant.
The
Process of Photosynthesis
It takes place inside the cell organelles known as
chloroplasts. Photosynthesis takes place in two stages the light stage and the
dark stage.
THE IMPORTANCE OF PHOTOSYNTHESIS IN THE REAL LIFE SITUATION
Importance
of photosynthesis in daily life:
1. All
organisms which are heterotrophy depend on autotrophy as source of food.
2. Living
organisms depend on oxygen for their aerobic respiration produced during
photosynthesis
3. Photosynthesis
convert light energy into chemical energy which is used by other organisms
4.
Humans depend on photosynthesis
for the energy containing fossil fuel which have developed over a millions of
year.
Properties
of Food Substance
The Basic
Food Substances and Their Properties
Basic food substances:
2. Protein
3. Lipids
CARBOHYDRATES
Is the
kind of food substance nutrients made up of carbon, hydrogen, and oxygen.
Example:
cassava,
maize, rice etc.
TYPES OF CARBOHYDRATES
1. Monosaccharide
2. Disaccharide
3. Polysaccharide
MONOSACCHARIDE:
Monosaccharide
is also known as simple sugar. They include glucose, fructose and galactose.
These sugars dissolve in water and form sweet solutions. Monosaccharide
are reduced sugar. The general formulae for monosaccharide is (CH2O)n
Where “n” represents a number of carbon atoms and have a value between 3
and 6. Example the formulae of glucose is (C6H12O6)
DISACCHARIDE:
This is
the kind of carbohydrate which is formed when two monosaccharide molecules
combine.
Two glucose molecules combine to form maltose. (C6H12O6) + (C6H12O6) condensation = C12H22O11+ H2O some disaccharide are reducing
sugars example lactose and maltose , other are non reducing sugar example
sucrose
POLYSACCHARIDE:
Is the type of carbohydrates formed by condensation involving several
monosaccharide Example starch, chitin etc
1. They are
not soluble in water
2. They are
non reducing sugar
3. They are
not sweet
4. When put
in water they form suspension
Common
Reagents and Chemicals used to Determine Food Properties
PROCEDURE
Dissolve the food sample in water Add an equal amount of Benedict
solution to the solution
Dissolve the food sample in water to get solution Put 2 cm of a solution
obtained in a test tube Add 1 cm of HCL acid
Boil the mixture Allow the mixture to cool Add small amount of sodium
hydroxide, shake the test tube after every additional continue until fizzing
stops Add 2 cm of Benedict solution then boil the mixture
TEST B FOR STARCH Add small amount of food sample solution in a test
food.Add few drops (2-3)of iodine solution in the food sample
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OBSERVATION
|
CONCLUSION
|
|
|
Food
sample dissolve
|
Reducing sugar
is
|
|
|
Color
change from blue to green to
|
||
|
present
|
||
|
orange,
yellow and finally brick red
|
||
|
|
||
|
FIZZING
|
|
|
|
COLOR CHANGE
FROM BLUE,
|
Non
reducing sugar
|
|
|
GREEN, YELLOW,
orange and
|
is
present
|
|
|
finally
brick red
|
|
|
|
Fizzing
|
|
|
|
Color change
from blue, green
to
|
Non
reducing sugar
|
|
|
yellow
to orange and finally brick
|
is
present
|
|
|
red
|
|
Color
change from blue to black Starch is
present
TEST FOR
CARBOHYDRATES
Food Tests for Reducing Sugars, Non Reducing Sugars, Starch, Proteins
and Lipids (Fats and Oil)
Carryout food tests for reducing
sugars, non reducing sugars, starch, proteins and lipids (Fats and Oil)
PROTEINS
FOOD
PROCESSING, PRESERVATION AND STORAGE.
The
Concept of Food Processing , Food Preservation and Food Storage
Explain the concept of food processing , food
preservation and food storage
Food processing refers to all the ways in which food is treated in order
to make it edible, appetizing and safe to eat or to keep it fresh for a long
time.
Some of
activities involved in food processing are;
1. Picking,
sorting and washing fruits and vegetables
2. Cooking
by boiling steaming, roasting backing or frying
3.
Converting raw materials into
other products for example making cheers from milk or sugar from sugar cane
FOOD PRESERVATION
Food preservation refers specifically to the methods of food processing
that areused to prevent food from spoiling or going bad
Methods
of food preservation
1. Keeping
out micro organisms for example by canning or bottling
2.
Using high temperature to kill
microorganisms that cause spoilage eg.By pasturalization and boiling
3.
Using very low temperature to
slow down the growth of microorganisms for example refrigeration.
4. Irradiation
which is by using radiations such as gamma rays to kill micro organisms
5.
Eliminating the moisture that is
needed for growth of micro organism for instance by drying, salting, smoking
etc
6. Adding
chemicals such as salt sugar, carbon monoxide to prevent physical changes in
food
FOOD STORAGE
Refers to the methods used to keep or reserve of
food for future use. Food storage can be done on a small scale at the family
level for example in a family granary or food store. Or large scale for large
populations e.g in government stores of grains.
The Importance of Food Processing, Preservation and
Storage
The
following are the importance of food preservation
1. prevents
wastage of food
2. it saves
money by preventing spoilage of food
3. maintains
the quality of food
4. prevents
the growth of micro organisms that can cause illness
5. improve
the flavor of food
6. removes
armful toxins and micro organisms from food
7. makes
food available even where they are not in season
8. enables
transportation of delecate and perishable food such as milk andfruit over long
distance
Traditional
and Modern Methods of Processing, Preserving and Storing Food
1. traditional
methods
2. modern
methods
TRADITIONAL METHODS
These are methods used to process and preserve food
which doesn‟t require the use of technology.
These are methods used to process and preserve food
which doesn‟t require the use of technology. The following are the traditional
ways.
CURING
It involves additional of substances such as salt,
sugar, spaces and vinegar to animal foods, moist meat and fish. Curing removes
water making it unavailable for the growth of microorganism it also improve the
taste of food. Sausages, be con and curried beef are made by curing meat.
DRYING IN THE SUN
Thus method is used to preserve rice, maize,
cloves, banana, beans, peas, meat, fish etc. Here food is left for long time on
the sun in order to reduce its moisture content. Reducing the amount of water
in food discourages the growth of microorganisms. Some food such as banana and
cassava are cut into small pieces to fasten the process.
SMOKING
Smoking is the traditional method which is used to
reduce moisture content of food to prevent growth of microorganisms. Grains,
meat, fish can be dried slowly over the smoking wood fire
COOKING
Traditional methods of cooking are simple and
include boiling, steaming, backing, in hot hash and roasting. These processes
help to soften food, improve flavor and preserve food. Example potatoes,
bananas, and maize can be boiled before being dried.
STORAGE IN GRANARIES AND PITS
Dry grains are stored in granaries which are
usually raised above the ground.The grains are sometimes mixed with neem leaf
ash or groundnuts oil to further prevent attack by microorganisms.Granaries
keep grains safe from insects rodents and birds. Example harvestedyams,
potatoes and cassava can be stored in large pits in the ground after drying.
ADVANTAGES OF TRADITIONAL METHODS
OF FOOD PROCESSING ANDPRESERVATION AND STORAGE
1. They are
simple and they can be done by most people
2. They use
locally available materials and simple technology thus keeping cost slow
3. No
harmful chemicals are added to the food
4. Curing
and smoking add distinct flavor.
5. Most
methods do not destroy nutrients
DISADVANTAGES:
1. Food can
be preserved and stored for the limited period of time
2. They are
manual and thus difficult to apply on a large scale
3.
Traditional methods are highly
limited in the variety of food that can beprocessed preserved and stored.
MODERN METHODS OF FOOD PROCESSING
AND PRESERVATION
REFRIGERATION AND FREEZING
Is the temporary storage of food at low temperature of up to 4
centigrade in order to slow down the growth of microorganisms. Freezing
involves storing food at very low temperatures in order to stop the growth of
microorganisms frozen food can be kept for months. Food that can be
refrigerated include milk, fresh fruits, vegetables, juice and butter. Freezing
is mostly used for meat, fish, fruits and vegetables.
PASTEURIZATION
Thus method of preservation was named after its inventor Louis Pasteur.
It involved heating food to a very highest temperature for a short time in
order to kill the micro organisms that can cause spoilage. Pasteurization
maintains the nutrients content and flavor of food. Examples of food that can
be pasteurized are milk and fruity juice.
CANNING AND BOTTLING
In this method, food is preserved by heating it in airtight vacuum,
sealed bottles or cans. The container is filled with food then the air is
pumped out to form a vacuum. The container is sealed and heated to kill
microorganisms and enzymes but not enough to overcook the food. Food that can
be bottled or canned include tomatoes, fruits, juice, beef, fish and packed
beans. Bottled or canned food can be kept for months or even years.
USING ADDITIVES
This method involved the use of chemicals such as sodium benzoate,
sodium chloride, and vinegar are added to food to slow down the growth of
microorganisms. This is commonly done to pressure fish and meat
DRYING
Food is dried by using either hot blast of air from a vacuum drayer.
After drying the food is then sealed in moisture –proof containers.
IRRADIATION
Is the modern method which involve the use of rays
of energy to stop the growth of microorganisms in stored food. Example in
onions, beans and potatoes. This makes food last longer. It also prevents
sprouting in onions and potatoes.
ADVANTAGES OF MODERN METHODS
1. Food can
last for many months and even a year
2. Modern
methods can process, preserve, and store large variety of food.
3. They are
advanced technology bused in fast and can handle huge quantities offood.
DISADVANTAGES OF MODERN METHODS
1. The
chemicals used can be harmful if eaten in excess
2.
These advanced technology involve
means where they are used only in certain areas for instance refrigeration
requires electricity.
3. The
process used for example canning and pasteurizing require special skills.
4. Sometimes
nutrients are lost thus lowering the nutritional value of food
DIFFERENCES BETWEEN TRADITIONAL
AND MODERN METHODS OF FOOD PROCESSING AND PRESERVATION
TRADITIONAL METHODS
Less costiful
It involves the use of low
technology
It processes and preserves food
for alimited amount of time
It uses local materials to
process and preserve food It is used by
most people
It select type of food to be
processed and preserved
MODERN METHODS
High costiful
It involves the use of advanced
technology
Preserves food for months and
evenyears
It uses chemicals to process and
preserve foodIt is used by
few people
It is not selective
The
Concept of Natural Environment
Natural environment is made up of all living and
non living things that occur naturally on earth. An organism living anywhere in
any environment is affected by the things around it such as air, water,
animals, plants, microorganism, stones, rock, soil, clouds and the sun.
everything around it in fact makes its natural environment. It is important to
understand that the environment includes all living things as well as non
living things.
IMPORTANT
TERMS
1.
Ecology: is the branch of biology
that deals with studying interaction oforganisms with their environment
2.
Population: is the total number
of organisms of the same species living in a certain area. Example the number
of frogs in a pond
3.
Community: this refers to the sum
of total of all population of different organisms living in a specific called
habitat
4.
Habitat: is the specific area
where an organism is found and adopted. i.e it is an appropriate for the
certain community example an ocean, grassland, and a pond
5. Ecosystem:
refers to a natural unit made up of living and non living things whose
interaction
BIOTIC
AND ABIOTIC COMPONENTS OF THE ENVIRONMENT
There are
two components of environment;
1. Biotic
(living things)
2. Abiotic
(non living things)
BIOTIC
COMPONENT
These are living components in the environment such
as animals, plants, fungi, and microorganisms. These organisms interact
together in number of ways and these ways of interaction include the following;
1.
Competition, that organisms must
compete for limited resources in struggle for life. For an organism to survive
in an ecosystem it must compete with partner for the limited resources.
2.
Predation Is the system in which
one organism utilize the other as food. The eater is a predator while the eaten
is a prey and a number of predators and preys regulate each other
3.
Symbiotic relationship This is
where there is a close relationship or association between organisms this
association could take various forms like mutualism, commensalism, and
parasitism
4.
Adaptation Adaptation has enabled
organisms to survive. They may be anatomically structurally physiologically or
behavioural. Eg some organisms are poisoners to their predator while others
while others develop warming colouration
ABIOTIC
COMPONENTS
These include non living organisms that are found
in ecosystem. Example air solar, energy, soil, and nutrients. Generally abiotic
components of an ecosystem consist of physical environment and they are as
follows:
1.
Climatic factor:Several change of
climatic condition influence or determine the survival of organisms in
ecosystem such condition include temperature, humidity, pressure etc
2.
Aquatic condition:Changes in the
aquatic environment and the nature of environment it is self determined by the
type of organism found in the area such a changes include water current, wave
action, salinity, etc
3.
Light condition factor:These
affect much plant population where photosynthetic process depend on the
availability of light.
4.
Soil factor/condition:These are
also adaphic factors and they include soil texture, soil structure and soil pH
Activity 1
Identify
various organism in their natural environment in the community
IMPORTANCE
OF NATURAL ENVIRONMENT
1. It is a
source of food to organisms
2. It
provides shelter and security for organisms
3. It allow
living and non living things to interact
4. It
provides an appropriate setting for organisms to reproduce andincrease in
number.
Hello, my name is Jack Sparrow. I'm a 50 year old self-employed Pirate from the Caribbean.
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