Lab Report for Food Test

Topics: Reducing sugar, Glucose, Sucrose Pages: 5 (1475 words) Published: September 30, 2011
INTRODUCTION: Carbohydrates are the product that made up from carbon, hydrogen and oxygen. Carbohydrates are form by the combination of carbon dioxide and water molecules. The carbohydrates contain two specific functional group in it which is the hydroxyl groups and carbonyl groups.A reducing sugar is a type of sugar with is an aldehyde group.This means that sugar can act as a reducing agent.The procces of reducing sugar is isomerisation,example of reducing sugar islactose,maltose,glucose and fructose.All monosaccharides are capable of reducing other chemicals such as copper (II) sulphate to copper oxide.Beside that disaccharides such as maltose and lactose are reducing sugar,however sucrose is non reducing sugar.Sugar exist in solution as an equliburum mixture of open chain and closed ring or in other words is cyclic structures.In the open chain form,the carbon contains special bond called carbonyl carbon.In closed ring form or cyclic structure the carbonyl carbon is the one attached to the (O) of the ring and OH group.This sugars is called reducing sugar because the oxidising agent is reduce during the reaction.Therefore non reducing sugar cannot be oxidised my mild oxidising agent. When the closed-ring (cyclic) structure of a monosaccharide opens to form a chain, the result can be divided into two which is an aldehyde or an ketone. Sugars that are aldehydes are known as aldoses. Sugars that are ketones are known as ketoses.Glucose and galactose are example of aldoses while fructose is an example of ketoses.There are few test can be done for testing these sugar to show or prove are they reducing sugar or non reducing sugar.Example of the test that can be done is Benedict test. 1 In plant,glucose is stored as the polysaccharide starch.Example of food that rich in starch is oat,cereal,rice and corn.Starch can be divided into two groups which is that is amylose and amylopectin. Natural starches are mixtures of amylose (10-20%) and amylopectin (80-90%). Amylose forms a colloidal dispersion in hot water whereas amylopectin is completely insoluble. The structure of amylose consists of a long polymer chains of glucose units connected by an alpha acetal linkage. Protein is a large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.protein also are required for the structure functions and regulation of the body cells,tissues and organs.There are a lot of protein in our body and each specific protein has it own unique function.Protein are also essential components of muscles, skin, bones and the body as a whole.Example of protein is enzymes,hormonoes and antinody. Protein are also one of the three types of nutrients used as energy sources by the body, the other two being carbohydrate and fat.

To identify and define differentiating between reducing and non-reducing sugars MATERIALS AND APPARATUS :
Test tube, test tube holder, tray, water bath, sucrose solution, maltose solution, glucose solution, lactose solution, Benedict’s reagent, dilute hydrochloric acid solution, sodium hydrogen carbonate solution, pH indicator, starch, iodine, potassium iodide solution, copper sulphate solution, potassium hydroxide solution, albumin water and stopwatch.

Test for reducing sugar
1.The water is brought into the water bath to achieve its boiling point and the source of heat were turn down 2.2 cm of the solution is taken to be tested and were added by 2 cm of benedict solution 3.The reagent was mixed throughtly

4.The test tube were placed in water bath and left for 5 minutes Results :

Solution Observation
Before testAfter test
Glucose Blue Brick-red
Maltose Blue Brick red
Lactose BlueBrick red
Sucrose BlueBlue

Test for Non reducing sugar
Method :
1.A non-reducing sugar sample was...
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Food Tests Lab Report Essay
  • Lab Report: Food Testing Essay
  • Test Essay
  • Lab Report Essay
  • Lab report Essay
  • lab report Essay
  • Identification of Macromolecules in Food Lab Report Essay
  • Lab Report Essay

Become a StudyMode Member

Sign Up - It's Free