Raffinose is a trisaccharide (C18H32O16) isolated from cottonseed meal. Raffinose doesnot reduce Tollens reagent, and it does not mutarotate. Complete hydrolysis of raffinosegives d-glucose, d-fructose, and d-galactose. When raffinose is treated with invertase,the products are d-fructose and a reducing disaccharide called melibiose. Raffinose isunaffected by treatment with a b@galactosidase, but an a@galactosidase hydrolyzes itto d-galactose and sucrose. When raffinose is treated with dimethyl sulfate and basefollowed by hydrolysis, the products are 2,3,4-tri-O-methylglucose, 1,3,4,6-tetraO-methylfructose, and 2,3,4,6-tetra-O-methylgalactose. Determine the completestructures of raffinose and melibiose, and give a systematic name for melibiose.
Carbohydrates
Carbohydrates are the organic compounds that are obtained in foods and living matters in the shape of sugars, cellulose, and starch. The general formula of carbohydrates is Cn(H2O)2. The ratio of H and O present in carbohydrates is identical to water.
Starch
Starch is a polysaccharide carbohydrate that belongs to the category of polysaccharide carbohydrates.
Mutarotation
The rotation of a particular structure of the chiral compound because of the epimerization is called mutarotation. It is the repercussion of the ring chain tautomerism. In terms of glucose, this can be defined as the modification in the equilibrium of the α- and β- glucose anomers upon its dissolution in the solvent water. This process is usually seen in the chemistry of carbohydrates.
L Sugar
A chemical compound that is represented with a molecular formula C6H12O6 is called L-(-) sugar. At the carbon’s 5th position, the hydroxyl group is placed to the compound’s left and therefore the sugar is represented as L(-)-sugar. It is capable of rotating the polarized light’s plane in the direction anticlockwise. L isomers are one of the 2 isomers formed by the configurational stereochemistry of the carbohydrates.
Raffinose is a trisaccharide (C18H32O16) isolated from cottonseed meal. Raffinose does
not reduce Tollens reagent, and it does not mutarotate. Complete hydrolysis of raffinose
gives d-glucose, d-fructose, and d-galactose. When raffinose is treated with invertase,
the products are d-fructose and a reducing disaccharide called melibiose. Raffinose is
unaffected by treatment with a b@galactosidase, but an a@galactosidase hydrolyzes it
to d-galactose and sucrose. When raffinose is treated with dimethyl sulfate and base
followed by hydrolysis, the products are 2,3,4-tri-O-methylglucose, 1,3,4,6-tetraO-methylfructose, and 2,3,4,6-tetra-O-methylgalactose. Determine the complete
structures of raffinose and melibiose, and give a systematic name for melibiose.
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