Food Tests Lab Report

Food Test 1 Test for Glucose with Benedicts answer Benedicts theme is used to ladder for simple sugars, such(prenominal) as glucose. It is a clear wild blue yonder root word of sodium and copper salts. In social movement of simple sugars, the blue closure changes coloration to either green, yellow or brick-red, depending on the summate of sugar. Method 1)Mix smalls amount of for each one diet audition (i. e. , nut lumen, cylindrical piece of potato thermionic tuber, cultivated cabbage crump and crisps) in variant run tubes with distilled water to make a liquid streamlet.Take round other test tube with glucose solution to bring as a see so as to comparability the difference in color subsequently the completion of the experiment. 2)Label each of the test tubes with a patsy for the substance. 3)Add 10 drops of Benedicts solution to each test tube. 4)Carefully heat the test tubes by suspending in a hot water bath development a 500 ml beaker at about 40-50 degr ees Celsius for five minutes. 5)Note either color change. Positive test for Glucose If sugar is present solution will turn from blue to green, yellow, or brick-red, depending on sugar concentration. A green precipitate means a little glucose was present. ?A red precipitate means glucose is present in vast amounts. Food Test 2 Test for Starch with tincture of iodine solution. Iodine solution is used to identify the presence of starch- a multifactorial carbohydrate. Iodine solution (potassium iodide solution) reacts with amylase a type of starch whereby a blue-black polyiodide complex is formed. Method 1)Mix smalls amount of each food samples (i. e. , Egg lumen, cylindrical piece of potato tuber, bread crump and crisps) in dissimilar test tubes with distilled water to make a liquid test.Take another test tube with starch solution to act as a control to compare the difference in color after the completion of the experiment. 2)Label each test tube with a marker for the substance. 3)Add 5 drops of iodine reagent solution to each test tube. 4)Note any color change. Positive Test for Starch The brick-red solution of iodine turns to blue-black. Food Test 3 Test for Protein with Biuret solution Biuret solution is used to identify the presence of protein. More accurately, it detects the presence of peptide bonds. Peptide bonds form a violet chelate complex with copper (II) ions present in the Biuret Reagent.Method 1)Mix smalls amount of each food samples (i. e. , Egg lumen, cylindrical piece of potato tuber, bread crump and crisps) in different test tubes with distilled water to make a liquid test. Take another test tube with protein solution to act as a control to compare the difference in color after the completion of the experiment. 2)Label each test tube with a marker for the substance. 3)Add 5 drops of Biuret reagent solution to each test tube. Shake gently to mix. 4)Note any color change. Positive test for proteins the solution will turn from blue to pink/ purple. Food Test 4 Test for Lipids the ethanol photographic emulsion test.Ethanol determines the presence of lipides i. e. , fats and inuncts. The solubilities of lipid in ethanol and water are utilise in this test since lipids are soluble in ethanol only not in water. So, if lipids are present a milky/ darksome white suspension is formed. Method 1)Add all different food samples (i. e. , Egg lumen, cylindrical piece of potato tuber, bread crump and crisps) in different test tubes. Also, take another test tube with Vegetable oil to act as a control to compare the difference in emulsion of the lipids after the completion of the experiment. 2)Label each test tube with a marker for the substance. )Add 5cm3 of ethanol to each test tube. Shake the sample with ethanol. 4)Pour some cold water into this mixture in the test tube. 5)Note whether the different solutions bewilder cloudy to prove the presence of lipid Positive test for lipid The solution changes into a cloudy-white emulsio n due to the suspension formed. Conclusion and rating (CE) Conclusion This test reveals the hidden fats, sugars, proteins and starch in food items. Compounds such as sugars and fats are present in living things. Though the food samples being tested had more than one compound present i. . , testis lumen contains starch, proteins and lipids Potato tuber contains starch, glucose and lipids Bread contains starch, glucose and slight lipids and crisps contain starch, glucose and lipids. Hence, different food samples have different compounds present. Evaluation ?Limitations i. The time the test tubes were unploughed in the water bath was not accurate. ii. The volume of food samples differ in each test tube for the same test. ?Improvements i. By using a stop watch for more accurate timing. ii. Set a fixed volume of food samples in each test tube.