Carbohydrates PDF

‫بسم هللا الرحمن الرحيم‬  Carbohydrates Definition of carbohydrates: Carbohydrates are substances containing carbon, hydrogen and oxygen having the general formula CnH2nOn. Hydrogen and oxygen are present in 2:1 ratio the same ratio as water  Carbohydrates They are polyhyd...

‫بسم هللا الرحمن الرحيم‬  Carbohydrates Definition of carbohydrates: Carbohydrates are substances containing carbon, hydrogen and oxygen having the general formula CnH2nOn. Hydrogen and oxygen are present in 2:1 ratio the same ratio as water  Carbohydrates They are polyhydroxy aldehydes or polyhydroxy ketones. CHO C=O OH Carbonyl group= Reducing sugar Glucose Galactose Fructose Classifications of Carbohydrates. Classifications of Carbohydrates. starch sucrose lactose Glucose Fructose  Starch α-glucose + glucose (α 1 - 4 glycosidic bond).  Lactose β- glucose + β galactose (β 1 - 4 glycosidic bond).  Sucrose α-glucose + β -fructose (α 1 - β 2 glycosidic bond). Fructose (Keto-Reducing) Glucose(Aldo-Reducing) Classification of Carbohydrates. monosaccharides disaccharides polysaccharides Aldoses sucrose Glucose starch Ketoses lactose fructose Reducing Non - Reducing 2S Glucose sucrose Fructose Lactose starch Aldo- sugar Keto - sugar Glucose Fructose  1-Molish test General test for all carbohydrates Why?????? It is general test for all carbohydrates How???? 3 ml of sugar + 3drops of alpha naphthol Shaking well Then add 2ml of concentrated H2SO4 slowly on the wall of tube Observation?????? violet ring at the junction of the two solutions Do the experiment (molish test) & demonstrate of the observation 2.Iodine test 5ml sugar + 2 drops of iodine Blue color  3-Fehling test Why????? It is reducig sugar or not How???/ 2ml of sugar + 2ml of fehling reagent Boiling 30 sec Observation???? red preciptate  3-Bendict test It is like fehling test but more sensitive , specific & stable Why???? It is reducig sugar or not How??? 1 ml of sugar + 5 ml of bendict reagent boiling 30 sec Observation???? red preciptate Do the experiments (fehling & bendict test) & demonstrate of their observation  4-Barfoed test Why???? It is reducing monosaccharide or not How?????? 1ml of sugar + 3 ml of barfoid reagent 4 min Observation???? Intermittent heating for Red preciptate + redness on the wall + red fumes Do the experiments (Barfoed test) & demonstrate of the observation  5-Seliwanoff test Why???? It is keto sugar (fructose) or not How?????? 1ml of sugar + 3ml of selwanoff reagent heating for 30 seconds Observation????? Red color Do the experiments (Seliwanoff test) & demonstrate of the observation Chemical examination Molish test Observation 3 ml of sugar violet ring at the junction + 3drops of alpha of the two solutions naphthol + 2ml of concentrated sulphoric acid slowly on the wall Chemical examination Iodine test Observation 5ml sugar + 2 drops of Dark blue colour iodine Test Observation Fehling red preciptate 2ml of sugar + 2ml of fehling + boiling Bendict 1ml of sugar + 5 ml of bindict + boiling Positive vs negative tests Test Observation Red preciptate + redness on the Barfoid test wall+ red Fumes 1ml of sugar + 3 ml of barfoid reagent + boiling for 5 min intermittent Selwanoff test Red color with keto sugar 1ml of sugar + 3ml of selwanoff + heating for 10 seconds after boiling Starch  Molish test 3 ml of sugar + 3drops of alpha naphthol + 2ml of concentrated sulphoric acid slowly on the wall = violet ring at the junction of the two solutions Iodine test 5ml sugar + 2 drops of iodine Blue color Acid hydrolysis of starch 5ml sugar+ 2ml diluted HCl Heat for 5 min Neutralization by equal amount of NaOH Do fehling , iodine test  Sucrose  Molisch test 3 ml of sugar + 3drops of alpha naphthol + 2ml of concentrated sulphoric acid slowly on the wall = violet ring at the junction of the two solutions Iodine test 5ml sugar + 2 drops of iodine No dark Blue color Fehling test It tests the reducing proprties of carbohydrates It depends on the prescence of free carbonyl group either keto or aldo group So all monosacchrides and some disacchrides are positive with this test. Fehling test 2ml of sugar + 2ml of fehling + boiling = red preciptate Bendict test It is like fehling test but more sensitive , specific & stable for longer time Both are used for detection of glucose in urine of diabitic patients 1 ml of sugar + 5 ml of bendict + boiling= Red preciptate Acid hydrolysis 5ml sugar+ 2ml diluted HCl Heat for 5 min Neutralization by equal amount of NaOH Do fehling Do selwanoff Structure of important disacchrides  Molish test 3 ml of sugar + 3drops of alpha naphthol + 2ml of concentrated sulphoric acid slowly on the wall = violet ring at the junction of the two solutions Iodine test 5ml sugar + 2 drops of iodine No dark Blue color Fehling test It tests the reducing proprties of carbohydrates It depends on the prescence of free carbonyl group either keto or aldo group So all monosacchrides and some disacchrides are positive with this test. Fehling test 2ml of sugar + 2ml of fehling + boiling = red preciptate Bendict test It is like fehling test but more sensitive , specific & stable for longer time Both are used for detection of glucose in urine of diabitic patients 1 ml of sugar + 5 ml of bendict + boiling= Red preciptate  4-Barfoed test Why???? It is reducing monosaccharide or not How?????? 1ml of sugar + 3 ml of barfoid reagent 4 min Observation???? Intermittent heating for NO Red preciptate + NO redness on the wall + NO red fumes How to write ? Physical examination Chemical examination Physical examination (COAR) Color Odour Aspect Reaction with litmuss paper All carbohydrates are : ▪ Colourless ▪ Odourless ▪ Clear ▪ Neutral Except starch : Whitish turbid Clear vs turbid 10 minutes to identify glucose solution via general scheme of biochemical experiments in lab  1-Glucose Physical properties: 1)color: Colorless 2)odor: odorless 3)Aspect: clear 4)Reaction: neutral Chemical properties: Test Observation Result 1)Biuret test No violet color It is not a protein 2)Molish test Violet ring at the junction It is a carbohydrate of 2 solutions 3)Iodine test No blue color It is not a starch 4)Fehling test Red precipitate It is a reducing sugar 5)Bendict test Red precipitate It is a reducing sugar 6)Barfoid test Red ptt & red fumes It Is a monosaccharide &reddness of the wall 7)Seliwanoff test No red color It is not a keto-sugar 10 minutes to identify fructose solution via general scheme of biochemical experiments in lab  2-Fructose Physical properties: 1)color: Colorless 2)odor: odorless 3)Aspect: clear 4)Reaction: neutral Chemical properties: Test Observation Result 1)Biuret test No violet color Itisnot a protein 2)Molish test Violet ring at the junction It is a carbohydrate of 2 solutions 3)Iodine test No blue color Itisnot starch 4)Fehling test Red ptt It is areducing suger 5)Bendict test Red ptt It is areducing sugar 6)Barfoid test Red ptt,red fumes It is amonosaccharide &reddness of the wall 7)Seliwanoff test Red color It is aketo sugar 10 minutes to identify lactose solution via general scheme of biochemical experiments in lab  3-Lactose Physical properties: 1)color: Colorless 2)odor: odorless 3)Aspect: clear 4)Reaction: neutral Chemical properties: Test Observation Result 1)Biuret test No violet color Itisnot aprotein 2)Molish test Violet ring at the It is a carbohydrate junction of 2 solution 3)Iodine test No blue color Itisnot starch 4)Fehling test Red ptt It is a reducing suger 5)Bendict test Red ptt It is a reducing suger 6)Barfoid test No red ptt,red fumes Itisnot a &reddness of the wall monosaccharide 5 minutes to identify sucrose solution via general scheme of biochemical experiments in lab  4-Sucrose Physical properties: 1)color: Colorless 2)odor: odorless 3)Aspect: clear 4)Reaction: neutral Chemical properties: Test Observation Result 1)Biuret test No violet color Itisnot aprotein 2)Molish test Violet ring at the junction of It is a carbohydrate 2 solution 3)Iodine test No blue color Itisnot starch 4)Fehling test No red ptt Itisnot areducing suger 5)Bendict test No red ptt Itisnot a reducing suger 6)Acid hydrolysis Sucrose solution is *Fehling after completely hydrolized to neutralization Red ptt Glucose:Reducing suger *Selliwanoff after Red color Fructose:Keto suger acid hydrol 5 minutes to identify starch solution via general scheme of biochemical experiments in lab  5-Starch Physical properties: 1)color: Whitish 2)odor: odorless 3)Aspect: turbid 4)Reaction: neutral Chemical properties: Test Observation Result 1)Biuret test No violet color Itisnot a protein 2)Molish test Violet ring at the junction It is a carbohydrate of 2 solution 3)Iodine test Blue color It is starch 4)Fehling test No red ptt Itisnot areducing suger 5)Bendict test No red ptt Itisnot areducing suger 6)Acid hydrolysis Starch is hydrolysed to: *Fehling after Red ptt Glucose:reducing suger neutralization *Iodine No blue color No starch