Lab Report for Food Test

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

References: : • http://www.ausetute.com.au/redsugar.html • http://www.askmehelpdesk.com/chemistry/reducing-non-reducing-sugars-137182.html • http://www.ehow.com/list_6982267_differences-between-reducing-non_reducing-sugars.html • http://courses.chem.psu.edu/chem34/handouts/ReducingSugars.pdf