Use appropriate chemical tests Essay Example for Free

Use appropriate chemical tests Essay P5 Use appropriate chemical tests to identify different dietary nutrients Minerals Biochemical test Positive results Why are they needed and the implications without them Starch The easiest way to test for starch is by adding an Iodine or potassium iodide solution. This is commonly used on bread. The iodine or potassium iodide solution will colour of the bread from brown to black. Starch influences the speed at which glucose is digested in the body. Starch converts into sugar and provides cells with energy. However if the cells do not require that energy, it is stored and used at a later time. Excess amounts of starch would turn into fat. Without a healthy supply of starch people would get tired and sluggish, due to the lack of energy in their body. Digestive difficulties, heart disease and kidney stones can also result from a lack of starch. Sugars (excluding sucrose) By adding Benedict’s solution, the substance being tested would need to be placed in a water bath and heated at 80Â °C in order to find out whether or not a sugar is present. If a sugar is found, the colour will change from blue to yellow/red. Sugar is used to fuel the human body. They do this by flowing into the bloodstream at a slower absorption rate which is healthy in the body. Without sugar people can become hypoglycemic which results in low energy levels and fainting. Sucrose sugar To test for sucrose the substance would need to be heated with dilute hydrochloric acid. This is so that that it can hydrolyse the sucrose to make glucose and fructose. When the colour changes from blue to green/yellow/red after hydrolysis, the Benedict’s test will be positive. This means that a sucrose sugar will be present. Sucrose is used in the body to make glucose. This process occurs in the liver where the sucrose is then split by hydrolysis. Like sugar they are used to provide energy to the cells. Without sucrose there could be a lower amount of glucose made. This can result in tiredness and potentially fainting. Lipids Ethanol is used to check for any lipids found in food. Once the ethanol is added, it would need to be shaken to reduce any fats. Once that process has finished the ethanol would need to poured into a test tube containing water. A white emulsion of fats should be present on top of the water. Lipids regulate the amount of fats in the body. These fats are then used as energy. Lipids also provide essential vitamins, regulate hormones and enzymes and protect the body. Without lipids all those functions would be reduced. Cell function and formation would be limited with a notable dip in energy also occurring. Absorption of nutrients would also be reduced as lipids regulate vitamin A, D, E and K in the body. Protein Add Biuret reagents of dilute sodium hydroxide on the substance. This is then followed by a dilute copper sulphate reagent. A colour change will occur is a lipid is present and the colour will change from blue to lilac or purple. Protein is essential in muscle development as it rebuilds and repairs them. Protein also manufactures antibodies which fight and prevent infection. A lack of protein would result in hair loss, slowness up healing and general weakness and lack of energy. Vitamin C DCPIP solution is added to the food substance being tested. If the blue colour of the DCPIP disappears then the food contains vitamin C. Vitamin C is needed for the production of protein collagen which help support body tissues. It also acts as a detoxifier as well as helping maintain blood vessel structure. Vitamin C deficiency would result in muscle and joint pains, easy bruising and tiredness. Gums may also start bleeding and swelling. Vitamins and Minerals A clean nichrome wire would need to be dipped in nitric acid and then placed on a Bunsen burner. The burner would need to be on its maximum heat setting and when there is no colour of the flame the nichrome wire has been removed of any contaminants. The wire would then need to be dipped in the food that it is being test. It is then placed on the Bunsen burner. The colours made are due to the minerals present in the food. The presence of potassium will produce a lilac flame. Calcium is present if the flame produces a red colour. If the flame is orange or yellow then sodium is present. Vitamins and minerals are split into a wide variety of beneficial substances. They ensure the body is functioning well. A deficiency in any of these would result in unhealthy development and poor cell function. Reference http://www. pearsonschoolsandfecolleges. co. uk/Secondary/Science/BTECAppliedScience/BTECLevel3NationalAppliedScience/Samples/StudentBook/BTECLevel3NationalAppliedScienceStudentBookUnit11. pdf http://www. ehow. com/how-does_4728406_sugar-affect-human-body. html#ixzz2K7KIoTsV http://www. ehow. com/about_4571150_does-vitamin-c-do-body. html#ixzz2K7QKUAsS. Read more:Â  Test for Carbohydrates