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Contents 1 Food Science and Nutrition 1.1 Food Choices 1.1.1 Factors affecting food choices 1.1.1.1 Availability of particular foods 1.1.1.2 Religious Reasons 1.1.1.3 Cultural Factors 1.1.1.4 Economic factors 1.1.1.5 Health Status 1.1.1.6 Nutritional Awareness 1.1.1.7 Lifestyle & Eating Patterns 1.1.1.8 Dietary Restrictions 1.1.1.9 Advertising and Marketing 1.1.1.10 Sensory Aspects of food 1.2 Proteins 1.3 Carbohydrates 1.3.1 Monosaccharides 1.3.2 Disaccharides 1.3.3 Polysaccharides 1.4 Lipids 1.5 Vitamins 1.5.1 Water Soluble Vitamins 1.5.2 Fat Soluble Vitamins 1.5.2.1 Vitamin A 1.5.2.2 Vitamin D 1.6 Minerals 1.6.1 Large Amounts 1.6.2 Small Amounts 1.6.3 Trace Amounts 1.6.4 Functions of Minerals 1.6.5 Calcium 1.6.6 Functions 1.6.7 Sources 1.6.8 Deficiency Symptoms 1.6.9 Iron 1.6.10 Potassium 1.6.11 Sodium 1.6.12 Zinc 1.6.13 Iodine 1.7 Water 1.7.1 Importance of Water 1.7.2 Properties of Water 1.7.3 Dietary Sources of Water 1.7.3.1 RDA 1.8 Related Links:

[edit] Food Science and Nutrition

[edit] Food Choices

The kind of food eaten by people varies from country to country and again within particular countries themselves.

[edit] Factors affecting food choices

There are many factors responsible for these food choices

• Availability of particular foods
• Religious reasons
• Cultural factors
• Economic factors
• Health Status
• Nutritional awareness
• Lifestyle / Eating patterns
• Dietary restrictions
• Sensory aspects
• Advertising and marketing

[edit] Availability of particular foods

Geographical location has always been a key factor in affecting food choices. Despite revolutionary advances in transport and food technology nowadays, climate, soil type and location are still rather important in determining food choices.

Seasonal production of food and geographical climate also affect the dietary habits of locals, especially in areas where food processing methods are not highly developed. Such examples can be seen in Southern Asia where rise is easily grown in the high temperatures and here in Ireland where the potato forms a significant part of our diet as they are easy to grow and are readily available.

Developments of modern food technology has meant that more foods are easily available due to the use of freezing, canning and drying.

[edit] Religious Reasons

Religious beliefs can affect food choices. Some groups do not believe in eating meat of any type, such as Buddhists and some Hindu's. Hindus do not eat beef especially, as they consider the cow a sacred animal. ROman Catholics are required to refrain from eating meat on only 2 days of the year, these being Ash Wednesday and Good Friday. Jews do not eat pork, the meat from the pig.

[edit] Cultural Factors

Foods habits vary from culture to culture as well as country to country. Some foods are eaten more in some countries than others. For example, Pasta is the principal food in Italy and rice is the staple diet of China and other Asian countries.

[edit] Economic factors

In developing countries, food is often scarce and the population are left with little choice as opposed to Western European countries who have a strong economy. Our food choices will be determined by the amount of money we have to spend. In developing countries foods that tend to be chosen are grain, maize etc which are cheap and not highly perishable like meat. Food choices in developed countries tend to be based on the individuals likes and dislikes rather than on what choice is available. A wide variety of food can be found all year round, making our choice rather varied than those in the developing world.

[edit] Health Status

It is a well known fact that regular meals and a variety of foods can contribute to good health. In recent years, there has been an increase in our consumption of fruit and vegetables as they have been linked to the prevention of certain types of cancer. The opposite of this can be seen in foods containing saturated fats such as butter and dairy produce because of the high risk of heart disease...

[edit] Nutritional Awareness

Nowadays, thanks to new studies, people have a greater knowledge of food and it's contribution to their health. Since the awareness of Heart Disease has heightened in recent years, there has been a decrease in the sales of butter and increase in sales of polyunsaturated oils and spreads. Nutritional information is now available on all food packages, given in the form of nutrients per 100g/100ml or per serving in some foods. These foods labels tell the consumer the amount of protein, carbohydrates, fats, vitamins, minerals, dietary fibre and energy that they will receive from each serving of that product.

[edit] Lifestyle & Eating Patterns

Nowadays, a greater number of women work outside the home than ever before. With this, people spend more time travelling to and from work and more people live alone, over the last number of years, the food manufacturers of the world have realised that they must help people adapt to this lifestyle. Now, more than ever, there are many different ready made meals on offer from cooked frozen meals, packaged mixes, ready to eat salads to take away foods and convenience foods which have all become increasingly popular. The idea behind these foods is that the manufacturers want us to spend less time preparing and cooking food so that we can spend more time at leisure activities.

[edit] Dietary Restrictions

Depending on illness and allergies, some people cannot eat particular types of food. For example people with gallstones must eat low - fat foods, people with gastric and duodenal ulcers must avoid spicy and fried foods. Similarly, Coeliacs cannot eat foods containing the wheat protein gluten so must have gluten free bread, pasta etc and Diabetics must control the sugar levels in their bodies.

There are also people who choose to have dietary restrictions such as Vegans who do not eat any animal products and Vegetarians who choose not to eat any meat.

[edit] Advertising and Marketing

The words such as "low fat", are terms used by marketing agencies to encourage a certain type of person to buy a particular food, this example would be attractive to the health conscious customer.Some foods or products can be presented to us as glamorous or luxurious, if you think of adverts you will be able to come up with some examples..such as Marks and Spencers dessert adverts. Packaging can be tailored to attract children or also to disguise an inferior product.

[edit] Sensory Aspects of food

In order for us to eat foods, they must satisfy the following 3 conditions:

• Appearance

Most of us judge food by it's appearance. We look at it's colour. Meals can be made more attractive by selecting a variety of colours in the food used rather than the same colours being used in one dish. The colour of food (fruit, vegetables) can also be used as an indication of the freshness of the food.

• Texture

From eating different types of food, we expect certain foods to have a particular texture, eg. biscuits should be crunchy rather than soft. The different textures of foods add variety to our diets such as crispy, tough or crunchy foods aswell as smooth or liquid foods.

• Flavour and Aroma

Taste and smell is how the flavour of food is divided. The taste of food is detected by our tongue, which sends a message to the brain and tells it whether we like the food or not. The smell of food can attract us to a certain food (eg. freshly baked bread or pizza), the smell can also put us off food (fish, rotten eggs etc)

[edit] Proteins

Proteins are composed of the elements Carbon(C), Hydrogen(H), Oxygen(O) and Nitrogen(N). Protein is the only nutrient that contains Nitrogen which is essential for growth. Some proteins also contain small amounts of Sulphur(S), Phosphorus(P) and Iron(Fe) The basic unit of a protein is an amino acid

                 H
                 |
                 |
        NH2------C------COOH
                 |
                 |
                 R

deamination

[edit] Carbohydrates

Carbohydrates are made up of the elements Carbon(C), Hydrogen(H) and Oxygen(O) They can be classified into:

[edit] Monosaccharides

• One sugar unit
• 
• Sources: Glucose, fructose, galactose
• Example: Fruit, honey, digested milk

[edit] Disaccharides

• Two sugar units
• 
• Sources: Sucrose, Lactose, Maltose
• Example: Table sugar, milk, barley

[edit] Polysaccharides

• Many sugar units
• 
• Sources: Starch, cellulose, pectin glycogen
• Example: Potatoes, fruit, stored animal starch

When amino acids join together to form disaccharides and polysaccharides, they lose a water molecule. ()

[edit] Lipids

Lipids are made of the elements Carbon(C), Hydrogen(H) and Oxygen(O). They are structured as one Glycerol molecule and three Fatty Acids.

        G
        L------FATTY ACID 1
        Y
        C
        E------FATTY ACID 2
        R
        O
        L------FATTY ACID 3

The type of Fatty Acid attatched changes, giving lipids different properties. The three types of fatty acid are:

1. Saturated: ie.All the carbon atoms are full with hydrogen atoms. There are no double bonds.
2. Mono-Unsaturated: ie.All the carbon atoms are not full with hydrogen atoms. There is ONE double bond.
3. Poly-Unsaturated: ie.All the carbon atoms are not full with hydrogen atoms. There are more than one double bonds.

[edit] Vitamins

Vitamins are classed into two types:

[edit] Water Soluble Vitamins

1. Vitamin B:

1. 1. Thiamine (B1)

Properties:

• Water souluble
• very unstable/lost at high temperatures
• Destroyed by alkalis
• lost in milling

Sources:

• Wholegrains
• sun flower seeds
• fortified bread
• beakfast cereals
• yeast
• eggs
• potatos

Functions:

• Release of energy from carbohydrate and fat
• Healthy nerve and muscle function
• Normal growth and development
• used in the manufacture of hydrochloric acid in the stomach

Effects of deficiency:

• Irritability
• Fatigue
• depression
• affects growth rate of children
• severe deficiency causes beri-beri

1. 1. Riboflavin (B2)

Properties

• Water soluble
• sensitive to light
• unstable at high temperatures
• Destroyed by alkalis

Sources:

• Beef
• Offal
• Milk
• eggs
• cheese

Functions:

• Release of energy from protein fat and carbohydrates
• Promotes healthy mucous membranes
• healthy skin hair and nails

Effects of deficiency

• Lack of energy and fatigue
• Skin rashes and dermatitis
• sore cracked lips and thongue
• eye disorders retared growth

1. 1. Niacin

Properties:

• Water soluble
• stable to heat
• Stable to acids and alkalis
• Lost in milling

Sources:

• Meat
• Offal
• Bread
• Tuna
• Nuts

Functions:

• Growth
• Energy release from food
• Healthy functioning of nervous system
• Promotes healthy skin

Effects of deficiency:

• Tiredness, depression adn memory loss
• if severe Pillagra

1. 1. Pyrodoxine(B6)

Properties:

• Water soluble
• fairly heat stabe
• Destroyed by alkalis

Sources:

• Meat
• Fish
• Offal
• Yeast
• Nuts

Functions:

• Metabolism of proteins carbohydrates and fat
• Involved in production of red blood cells
• Maintaining a healthy nervous system
• Releaves symphtoms of premenstrual tension and nausia in pregnancy

Effects of Deficiency:

• May cause irritability and insomnia
• Premenstrual syndrome
• Nausea in pregnancy

1. 1. Cobalamin (B12)

Properties:

• Water soluble
• Some loss in cooking
• Destroyed by acids and alkalis

Sources:

• Liver
• Meat
• Milk
• Eggs
• Cheese
• Fish

Functions:

• Involved in metabolism of fatty acids and folate
• Required for the production of red blood cells
• Promots normal growth
• Maintains a healthy nervous system

Effects of deficiency:

• Weakness, Fatigue
• Deterioration of nerve fibres
• can cause pernicious anaemia

1. 1. Folate/Folic acid

Properties:

• Water soluble
• Some loss in cooking
• Destroyed by alkalis
• stable to acids

Sources:

• Spinach
• Milk
• Fortified breakfast cereals
• wholemeal bread

Functions:

• Essential for the formation of new cells in the foetus
• Needed for the synthesis of genetic material
• Involved in the formation of red blood cells
• Helps maintain the immune system

Effects of deficiency:

• Spina Bifida
• Anamia and fatigue in young children and pregnant woman

1. Vitamin C (Ascorbic Acid)

[edit] Fat Soluble Vitamins

[edit] Vitamin A

1. Retinol

• Sources include liver cod liver oil, cheese and butter
• Functions

1. for vision in dim light
2. regulates growth
3. maintaining lining of mouth , respiratory and urniary tracts
4. promotes healthy skin

• Deficiency of vitamin A

1. night blindness
2. drying of the tear ducts
3. poor growth / stunted growth
4. increased susceptibility to infection

• Properties

1. yellow fat soluble vitamin
2. insoluble in water
3. stable to all cooking but destroyed to high temps such as frying

2. Beta-Carotene

• It is called a pro vitamin a because carotene is converted to vitamin a in the gut and liver but only bout 1/4 is converted to vitamin a

[edit] Vitamin D

• Cholecalciferol - is the ultra violet lights on 7 dehydrocholestrol in the skin .
• Ergerciferol - also vitamin D its the ultra violet lights on the yeast and fungi.
  • Functions

1. for absorbtion of calcium & phorphorus for bones and teeth
2. regulates calcium between skelton and blood
3. prevents rickets

• • Deficiency

1. Rickets in young children
2. osteomalcia is similar to rickets only in adult form
3. osterporosis
4. dental decay

====Vitamin E ====(Tocopherol)

====Vitamin K==== (Naphtho-Quinones)

[edit] Minerals

For each mineral you must know sources, functions, deficiences and RDAs. Calcium and Iron need more specific details.

The body needs 20 essential vitamins. These are needed in large, small and trace amounts.

[edit] Large Amounts

• Iodine
• Iron
• Sodium
• Calcium
• Potassium
• Magnesium
• Sulphur
• Phosphorus
• Chlorine

[edit] Small Amounts

• Zinc
• Iron
• Iodine
• Copper

[edit] Trace Amounts

(HL only)

• Flourine
• Tin
• Selenium
• Nickel
• Molybdenum
• Vandium
• Chromium

[edit] Functions of Minerals

• Minerals are used to form an essential part of some vitamins and proteins.
  • Iron in Haemoglobin
  • Iodine in the Hormone Thyroxine
  • Cbalt in Vitamin B

• Minerals are the main constituents in bones and teeth which are made almost completely of phosphorus, magnesium and calcium.

• Minerals are part of muscles and organs such as the liver and heart which contain small amounts of copper, potassium, iron, zinc and phosphorus.

[edit] Calcium

The body has a greater percentage of calcium than any other mineral. It is found in the bones mostly, with small amounts in the muscles and blood.

[edit] Functions

1. Formation of healthy bones and teeth
2. Calcification - The layering down of Calcium & Phosphorus in bones and teeth.
3. Proper functioning of nerves, blood and muscles

[edit] Sources

Green vegetables, tinned fish (bones softened during canning), cheese, milk, hard water, fortified flour & foods

[edit] Deficiency Symptoms

1. Irritability
2. Muscular Spasm
3. Osteomalacia (softening or weakening of bones in aduts, especially females after multiple pregnancies)
4. Rickets (malformed bones in children)
5. Osteoporosis

• • Also known as Brittle Bone disease.
  • A calcium deficiency
  • Accelerated bone loss especially in post - menopausal women.
  • Most common in females as they may lose calcium during childbearing years.
  • If not enough calcium is present during pregnancy, calcium will be taken from the mothers bones to supply the fetus.
  • It is important for teenage girls to build up a good store of calcium in their bones.

• RDA:
  • Children: 800mg
  • Adolescents: 1200mg
  • Adults: 800mg
  • Pregnant/lactating women: 1200mg

[edit] Iron

• RDA:
  • Children: 8mg
  • Adolescents: 14mg
  • Adults: 10mg
  • Pregnant/lactating women: 15mg

[edit] Potassium

• RDA: .8-3.1 g

[edit] Sodium

• RDA: 1.6 g

[edit] Zinc

• RDA:7-12 g

[edit] Iodine

• RDA:70-160 micrograms

[edit] Water

Water consists of tiny particles called molecules. Each molecule is composed of Hydrogen (H) and Oxygen (0)atoms in the ratio of 2:1. Water is known as H2O

[edit] Importance of Water

• Quenches thirst
• Transports vital nutrients, oxygen and hormones throughout the body
• Is a source of minerals such as calcium & flourine
• Evaporation of water from the skin cools the body
• Helps remove waste matter from the body via urine
• Is an essential part of all body tissues e.g blood, sweat, saliva
• Hard water, appears to have a protective effect against coronary heart disease (possibly due to it's acidic nature)

[edit] Properties of Water

1. has no colour, taste or smell
2. Is a good solvent
3. Evaporates @ over 100 degrees Celsius
4. Is neither acidic nor alkaline
5. Freezes @ 0 degrees Celsius and boils at 100 degrees Celsius

[edit] Dietary Sources of Water

Most foods and all drinks contain water. About 1 litre is taken into the body daily in the form of drinks, 1 litre daily from water content food and approximately a quarter of a litre from the oxidation of fats, carbohydrates and proteins.

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[edit] RDA

2 - 2.5 litres per day

[edit] Related Links:

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