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UNIVERSIDAD NACIONAL SAN ANTONIO ABAD DEL CUSCO ESCUELA DE POST GRADO. CARBOHIDRATOS – Polisacaridos. MAESTRIA EN CIENCIA Y TECNOLOGIA DE ALIMENTOS. Dra. Celina Luízar Obregón. COMPOSICION Y ANÁLISIS DE ALIMENTOS EPA 01ACT. Polisacáridos. Polisacáridos. Clasificación de los Polisacáridos.
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UNIVERSIDAD NACIONAL SAN ANTONIO ABAD DEL CUSCO ESCUELA DE POST GRADO CARBOHIDRATOS – Polisacaridos MAESTRIA EN CIENCIA Y TECNOLOGIA DE ALIMENTOS Dra. Celina Luízar Obregón COMPOSICION Y ANÁLISIS DE ALIMENTOSEPA 01ACT
Clasificación de los Polisacáridos Homopolisacáridos de glucosa: • enlace a: almidón, glucógeno (reserva energía) • enlace b: celulosa (fibras pared celular) Heteropolisacáridos: Ej., proteoglicanos de la matriz extracelular
Almidón • Starchisusedforenergystorage in plants • it can beseparatedintotwofractions; amylose and amylopectin. Eachon complete hydrolysisgivesonly D-glucose • amyloseiscomposed of continuous, unbranchedchains of up to 4000 D-glucoseunitsjoinedbya-1,4-glycoside bonds • amylopectinis a highlybranchedpolymer of D-glucose. Chainsconsist of 24-30 units of D-glucosejoinedbya-1,4-glycoside bonds and branchescreatedbya-1,6-glycoside bonds
Plantsstore glucose as amylose or amylopectin, glucose polymers collectively called starch. Glucose storage in polymeric form minimizes osmotic effects. Amylose is a glucose polymer with a(14) linkages. The end of the polysaccharide with an anomeric C1 not involved in a glycosidic bond is called the reducing end.
=> Amilosa • Soluble starch, polymer of D-glucose. • Starch-iodide complex, deep blue. Chapter 23
Amylopectin Branched, insoluble fraction of starch. => Chapter 23
AMILOPECTINA Almidón y glucógeno
Amylopectin is a glucose polymer with mainly a(14) linkages, but it also has branches formed by a(16) linkages. Branches are generally longer than shown above. The branches produce a compact structure & provide multiple chain ends at which enzymatic cleavage can occur.
Celulosa • Cellulose is a linear polymer of D-glucose units joined by b-1,4-glycoside bonds • it has an average molecular weight of 400,000, corresponding to approximately 2800 D-glucose units per molecule • Both rayon and acetate rayon are made from chemically modified cellulose
Cellulose, a major constituent of plant cell walls, consists of long linear chains of glucose with b(1®4) linkages. Every other glucose is flipped over, due to b linkages.
This promotes intra-chain and inter-chain H-bonds and van der Waals interactions, that cause cellulose chains to be straight & rigid, and pack with a crystalline arrangement in thick bundles - microfibrils.
n Celulosa b-Glucanos: Celulosa
Celulosa Acetato celulosa - CH3COOH
Nitro celulosa Si de algodón y menor grado de esterificación = algodón pólvora o piroxilina HNO3- H2SO4
Celuloide Celulosa Alcanfor Piroxilina (Grado de nitración 2) Mezcla gelatinizada Primer plástico moldeable de principios siglo pasado Descubierto por John WesleyHyattt Sustituto del marfil para bolas de billar (explosivas)
CarboxiMetil celulosa Carboxymethylcellulose; carmellose; E466 Se trata la celulosa con NaOH concentrada y caliente (cadenas de menor Pm) y después tratar con un R-Cl Espesante y cambiador de cationes
CarboxiMetil celulosa Carboxymethylcellulose; carmellose; E466 Carboxymethylcellulose (CMC) orcellulosegum[1]iscellulosederivativewithcarboxymethylgroups (-CH2-COOH) boundtosome of thehydroxylgroups of theglucopyranosemonomersthatmake up thecellulosebackbone. Itisoftenused as itssodiumsalt, sodiumcarboxymethylcellulose.
Dietilaminoetil celulosa Diethylaminoethyl cellulose (DEAE or DEAE-C) is a positively charged resin used in ion exchange chromatography, a type of column chromatography, used in protein and nucleic acid purification/separation. Gel matrix beads are derivatized with DEAE and lock negatively charged proteins or nucleic acids into the matrix, until released by increasing the salt concentration of the solvent. DE52 has a pKa of 11.5. DEAE-Dextran (DEAE-D) is also used for transfecting animal cells with foreign DNA. It is added to solution containing DNA meant for transfection. It binds and interacts with negatively charged DNA molecules and via a largely unknown mechanism brings about the uptake of nucleic acids by the cell. This procedure is highly suited for transient transfection used for various molecular biology studies.
Dietilaminoetil celulosa Farmacia - laxante Si R= -CH2 -CH2 –N(CH2 –CH3 )2 Espesante y cambiador de aniones Muy utilizado como cambiador de aniones