Disaccharides Invert sugar and other
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Transcript of Disaccharides Invert sugar and other
DISACCHARIDES
DISACCHARIDES
• Sugars composed of two mono saccharide units joined by α -Glycosidic bond.
• MALTOSE14
• SUCROSE 12
• LACTOSE 14
• LACTULOSE14
• TREHALOSE11
MALTOSE
• COMPOSITION • O α- D- Glucopyranosyl (1-4) α-D-
Glucopyranosyl • MALT sugar• SOURCES • Malt, germinating cereals, enzymatic
hydrolysis of starch by salivary & pancreatic Amylases.
• Maltase enzyme hdrolyzes Maltose into Glucose.
• strong reducing agent.• Shows muta rotation.• Forms sun flower shaped Osazone crystals.
ISOMALTOSE• Enzymatic hydrolysis of branch points of the
AMYLOPECTIN unit of Starch.
• Shows α-(1-6) linkage.
LACTOSE
• SOURCES
• Milk ,pharmaceutical preparations.
• COMPOSITION
• O-β -D- Galactopyranosyl (1-4)-β- D- Glucopyranosyl
• Synthesized in mammary glands ,can appear in the urine of lactating mothers.---LACTOSURIA.
• COW S’ milk contains 45% Lactose.
• Human milk contains 74% Lactose.
• Reducing sugar ,shows muta rotation.
LACTOSE INTOLERANCE
• Lactase deficiency
• Diarrhea ,flatulence , dehydration .
• Treatment
• Stop breast feeding/ milk intake.
• Yoghurt ,cheese & green vegetables for Ca++
intake.
• Lactase pills.
LACTULOSE• O-α –D Galactopyranosyl (1-4 )-β-D Fructopyranosyl
• SOURCES
• Heated Milk , synthetically produced .
• Can not be hydrolyzed by intestinal enzymes .
• Fermentation by intestinal bacteria .
• USES
• Mild Diuretic /osmotic laxative .
SUCROSE (TABLE SUGAR )
• O α -D –Glucopyranosyl (1-2) β- D- fructofuranose
sources
• Cane ,beetroot,sorgham,fruits & vegetables.
• Non reducing sugar ,
• Does not form Osazone crystals.
• Does not exhibit muta rotation .
• Dextro rotatory sugar ( + 66.5 )
• On hydrolysis it becomes strongly Levorotatory (- 28.2)
• INVERT SUGAR• Hydrolytic products of Sucrose are called invert sugars.• Sucrose hydrolysis by Sucrase/ dilute acids liberates
one molecule each of α D- Glucopyranose & β –D Fructofuranose.
• β D- Fructofuranose form is unstable & immediately gets converted to β –D Fructopyranose form, which is strongly Levorotatory ( -92 )
• Overall effect is INVERSION of dextro rotatory Sucrose (+66.5) to Levorotatory.( - 22.8)
• Invert sugars are 33% more sweet than Sucrose i.e. Honey
TREHALOSE
• O α-D Glucopyranosyl (1-1) α-D Glucopyranosyl
• SOURCES
• Fungi, yeast
OLIGO SACCHARIDES
• 3-10 carbohydrate units.
• Components of integral membrane proteins, present on their extra cellular domain.
• Mostly contain Mannose /Sialic acid residues.
• Help in degradation of these integral proteins.
• EXAMPLES
• Glycoproteins
• Antibodies
• Coagulation factors