Food

Why do we need food? To supply energy to live, move and survive To grow, and to repair damaged cells and tissues in our body. To keep warm. To prevent diseases.

Breads and Cereal Group 6 or more servings FOOD PYRAMID Fats, Oils and Sweets use occasionally Milk Group 2 servings Meat Group 2 servings Fruit Group 2-4 servings Vegetable Group 3-5 servings Breads and Cereal Group 6 or more servings

Balanced Diet A balanced diet contains the right amount of each of the different types of food

NUTRIENTS AND THEIR FUNCTIONS CARBOHYDRATES for energy Protein for growth and repair FATS for energy and warmth VITAMINS and MINERALS to keep us healthy and to prevent diseases

Carbohydrates Starch Sugar Fibre

Test for starch

To test for the presence of Starch Apparatus Iodine in dropper and Starch Sample ie Potato or bread Method Using the dropper , place a few drops of iodine on your sample Note the change in colour if any Result The sample turned _______ Conclusion Iodine turned from brown to Blue/Black. This indicates that starch is present.

Fats Insulation Energy Protection

To test for the presence of Fats Apparatus Brown paper and fat sample Method Place a small amount of butter on a piece of brown paper Allow to dry Hold the paper up to the light Result The spot turns _______ Conclusion Translucent Spot indicates that fat is present

Proteins Growth and repair of cells Make enzymes and hormones

Vitamins C to prevent scurvy D to prevent rickets

Minerals Iron to prevent anaemia Calcium bone & teeth

Water Solvent Transportation of substances around body

Food Types and its Functions Sources Carbohydrates Starch Sugars Fibre To provide energy To prevent constipation Fruits & jams Potato,bread,rice & Pasta Cereals & Green Veg Proteins Growth and repair of cells Fish, Milk, Nuts & Meat Fats Insulation Milk, Butter & Oil Vitamins C to prevent scurvy D to prevent rickets Oranges & Lemons Skin& Dairy products Minerals Iron to prevent anaemia Calcium bone & teeth Liver, Meat ,Veg Milk, cheese Water Solvent Transportation of substances around body Tea

Scurvy Definition A condition characterized by general weakness, anaemia, gum disease (gingivitis), and skin haemorrhages resulting from a lack of Vitamin C in the diet.

Prevention?!

Rickets

Rickets Deficiency in Vitamin D. Prevention??

Food Tests

To test for the presence of Reduced Sugars Apparatus Glucose solution, Benedicts solution, test tubes, water bath Method Set up the test tube rack, with 4 test tubes A,B, Place 5mls of water in A and 5mls of glucose solution into B Add Benedicts solution to A and B Place test tubes into a beaker of hot water on a hot plate Note Results Result The B solution _______ The D solution turns _______ Conclusion Brick red colour in D indicates that reduced sugars is present

Examples of Protein

Examples of Protein

To test for the presence of Protein Apparatus Test tubes and test tube rack Sodium Hydroxide Solution & Copper Sulphate Solution & Milk Method Add 5cm3 of milk and water to two separate test tubes Using the dropper add Sodium hydroxide solution( Colourless) and then Copper Sulphate solution ( blue) Note the change in colour if any Result The milk sample turned _______ Conclusion Violet/Purple indicates that protein is present

Examples of Fat

Energy values Different foods contain different amounts of energy. These amounts are known as Energy Values. Energy is measured in Joules (J). However energy values of a food can be measured in Kilojoules per 100 gram. All foods are supposed to display nutritional information on their packets; the table of information on the right was given on a packet of wheat bran.

http://www.coca-cola.ie/health/work-it-out-calculator.html#

To show that there is energy in food: Conversion of chemical energy to heat energy Apparatus Beaker, tripod, bunsen burner, gauze, thermometer, mounted needle & peanut. Method Place 100mls of cold water into the beaker on the tripod with the gauze Note the temperature using the thermometer Place the peanut on the mounted needle and hold under a bunsen flame until it is alight Hold the burning peanut under the beaker After the peanut is finished burning , note the new thermometer of the water Result The temperature of the water has risen Conclusion As the peanut burns chemical energy is converted into heat energy which results in a rise in the temperature of the water

Summary The range of food that an animal eats is its DIET Functions of food include tp provide energy and to provide material for growth Food types: Carbohydrates, Fats, Proteins, Minerals and Vitamins. Foods content chemical energy The amount of energy present in food per 100g is given on the food label A Balanced diet contains the correct amount of all of the food groups A diet must be balanced in terms of energy A food pyramid recommends the daily intake of each of the different food groups