OBJECTIVE
The main purpose of the experiment is to understand some general tests that detect fats,proteins and carbohydrates in foods.
INTRODUCTION
Carbohydrates are also known as sacharides. There are 4 main groups of carbohydrates,which are monosaccharides, disaccharides, oligosaccharides and polysaccharides. Carbohydrates play an important role in living organism as it is the energy storage, and it also plays an important role in structural of living organisms. There are various of test can be done to identified the present of carbohydrates in foods but the few most well-know are the Molisch test, Bennedict test and the iodine test.
Proteins are made up of amino acids, which are the simplest unit of proteins. The few maintests to identify the present of the proteins are Xanthoprotic test, Biuret test and also Ninhydrin test.The test used to identify the present of fats are the Grease spot test. This can be carried out by using a piece of filter paper. Although it cannot identify the types of fats present but it can show the present of fats.
APPARATUS
1.pH papers
2.Parafilm sheets
3.Filter paper
4.Test tubes and holder
5.Stir rod
6.Droppers
7.25ml of beaker
8.10ml measuring cylinder
PROCEDURE
PART A:TEST FOR DETECTING CARBOHYDRATES
1. MOLISCH TEST
a)Small paper labels,number five clean test tubes are using as directed below: i. 20 drops of deionized water(control) ii.20 drops of 1% glucose solution(1g of glucose is added in 99ml distilled water) iii.20 drops of 1% sucrose solution iv.20 drops of 1% lactose solution v.20 drops of 1% starch solution(1g of starch is added in 99ml distilled water and put in boil) b) Add 3 drops of Molisch reagent to each of the five test tubes,3 drops of Molisch reagent is added.Each test tube is seal with Parafilm® and each tube is shook to ensure mixing.Then,the test tube is inclined at 45%
References: 1.Division of Chemical Education,Inc,American Chemical Society.Benedict’s test for reducing Sugar.2001. 2.http://www.chem.ucalgary.ca/course/351/Carey5th/Ch27/ch27-3-3.html 3. http://homepages.ius.edu/dspurloc/c122/casein.htm