CARBOHIDRATOS

CARBOHIDRATOS PolisacaridosDra. Celina Luzar ObregnUNIVERSIDAD NACIONAL SAN ANTONIO ABAD DEL CUSCOESCUELA DE POST GRADOCOMPOSICION Y ANLISIS DE ALIMENTOS

EPA 01ACTMAESTRIA EN CIENCIA Y TECNOLOGIA DE ALIMENTOSPolisacridos

6666Polisacridos

Clasificacin de los PolisacridosHomopolisacridos de glucosa:

enlace a: almidn, glucgeno (reserva energa) enlace b: celulosa (fibras pared celular)

Heteropolisacridos: Ej., proteoglicanos de la matriz extracelular6666

5Clasificacin de los Polisacridos

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Clasificacin de los Polisacridos

Posicin reductora y no reductora10Polisacridos

Polisacridos

6666AlmidnStarch is used for energy storage in plantsit can be separated into two fractions; amylose and amylopectin. Each on complete hydrolysis gives only D-glucoseamylose is composed of continuous, unbranched chains of up to 4000 D-glucose units joined by a-1,4-glycoside bondsamylopectin is a highly branched polymer of D-glucose. Chains consist of 24-30 units of D-glucose joined by a-1,4-glycoside bonds and branches created by a-1,6-glycoside bonds6666Plants store 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.

Chapter 2315AmilosaSoluble starch, polymer of D-glucose.Starch-iodide complex, deep blue.

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AMILOSAChapter 2317AmylopectinBranched, insoluble fraction of starch.

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AMILOPECTINAAlmidn y glucgenoAmylopectin 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.

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Grnulos de almidn en un embrin de juda

Grnulos de almidn en un embrin de judaCelulosaCellulose is a linear polymer of D-glucose units joined by b-1,4-glycoside bondsit 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 cellulose6868Cellulose, a major constituent of plant cell walls, consists of long linear chains of glucose with b(14) 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.

b-Glucanos: CelulosaCelulosa

n

- CH3COOH

CelulosaAcetato celulosa

HNO3- H2SO4

Nitro celulosaSi de algodn y menor grado de esterificacin = algodn plvora o piroxilinaCelulosaCeluloidePiroxilina (Grado de nitracin 2)

AlcanforMezcla gelatinizadaPrimer plstico moldeable de principios siglo pasadoDescubierto por John Wesley HyatttSustituto del marfil para bolas de billar (explosivas)

Espesante y cambiador de cationesCarboxi Metil celulosaSe trata la celulosa con NaOH concentrada y caliente (cadenas de menor Pm) y despus tratar con un R-Cl

Carboxymethylcellulose; carmellose; E466Carboxi Metil celulosa

Carboxi Metil celulosa

Carboxymethylcellulose; carmellose; E466Carboxymethyl cellulose(CMC) orcellulose gum [1]is cellulosederivativewith carboxymethyl groups (-CH2-COOH) bound to some of thehydroxylgroups of the glucopyranosemonomersthat make up the cellulosebackbone. It is often used as its sodiumsalt, sodium carboxymethyl cellulose.Dietilaminoetil celulosaDiethylaminoethyl cellulose(DEAEorDEAE-C) is a positively charged resin used inion exchange chromatography, a type ofcolumn 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 apKaof 11.5.

DEAE-Dextran(DEAE-D) is also used fortransfectinganimal 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 ofnucleic acidsby the cell. This procedure is highly suited for transient transfection used for variousmolecular biologystudies.Farmacia - laxanteEspesante y cambiador de anionesMuy utilizado como cambiador de aniones

Si R= -CH2 -CH2 N(CH2 CH3 )2Dietilaminoetil celulosaChapter 2351GlycogenGlucose polymer, similar to amylopectin, but even more highly branched.Energy storage in muscle tissue and liver.The many branched ends provide a quick means of putting glucose into the blood.

=>Glycogen, the glucose storage polymer in animals, is similar in structure to amylopectin. But glycogen has more a(16) branches. The highly branched structure permits rapid glucose release from glycogen stores, e.g., in muscle during exercise. The ability to rapidly mobilize glucose is more essential to animals than to plants.

GlucgenoGlycogen is the reserve carbohydrate for animalsLike amylopectin, glycogen is a nonlinear polymer of D-glucose units joined by a-1,4- and a-1,6-glycoside bonds bondsThe total amount of glycogen in the body of a well-nourished adult is about 350 g (about 3/4 of a pound) divided almost equally between liver and muscle6767

Glucgeno

Grnulos de glucgeno en el citoplasma de un hepatocito

aAlmidn y glucgenoRamificacin: amilopectina, 4%; glucgeno, 10%Chapter 2357ChitinPolymer of N-acetylglucosamine.Exoskeleton of insects.

Chapter 2358Chitin

Chitin is a long-chainpolymerof aN-acetylglucosamine, a derivative ofglucose, and is found in many places throughout the natural world. It is the main component of thecell wallsoffungi, theexoskeletonsofarthropodssuch ascrustaceans(e.g.,crabs,lobstersandshrimps) andinsects, theradulasofmollusks, and the beaks ofcephalopods, includingsquidandoctopuses. In terms of structure, chitin may be compared to the polysaccharidecelluloseand, in terms of function, to the proteinkeratin. Chitin has also proven useful for several medical and industrial purposes

QuitinaChitin is used in industry in many processes. It is used as an additive to thicken and stabilize foods andpharmaceuticals. It also acts as a binder indyes,fabrics, andadhesives. Industrialseparation membranesandion-exchangeresinscan be made from chitin. Processes tosizeand strengthenpaperemploy chitinQuitina60PectinasPectin(fromGreek-pektikos, "congealed, curdled"[1]) is a structuralheteropolysaccharidecontained in the primarycell wallsofterrestrial plants. It was first isolated and described in 1825 byHenri Braconnot.[2]It is produced commercially as a white to light brown powder, mainly extracted fromcitrus fruits, and is used in food as agelling agentparticularly injamsand jellies. It is also used in fillings, sweets, as a stabilizer in fruit juices and milk drinks and as a source ofdietary fiber.

61PectinaPectins are a family of complex polysaccharides that contain 1,4-linked -D-galactosyluronic acid residues. Three pectic polysaccharides have been isolated from plant primary cell walls and structurally characterized. These are:HomogalacturonansSubstituted galacturonansRhamnogalacturonans62PectinaPectins are the major components of most higher plant cell walls; they areparticularly prevalent in fruits and vegetables. Commercial pectins are prepared mostly from some by-products of the food industry, such as apple pulp, citrus peels, and sugarbeet pulp. Pectins are the most complex class of plant cell wall polysaccharides. They comprise of two families of covalently linked polymers, galacturonans and rhamnogalacturonans (type I)

63Gomas

Exudate gums are polysaccharides produced by plants as a result of stress, including physical injury and/or fungal attack. Gum arabic, gum tragacanth, gum karaya, and gum ghatti have been used by humans for many thousands of years in various food and pharmaceutical applications. Generally, these gums are structurally related to arabinogalactans, galacturonans, or glucuronomannans .They all contain a high proportion of glucuronic or galacturonic acid residues (up to 40%).

GomasGomas

Goma Arbiga (goma acacia)

Lagoma arbiga(E-414) es unpolisacridode origen natural que se extrae de a resinaderbolessubsaharianos (Acacia senegalyAcacia seyal) como parte del proceso de cicatrizacin de stos (gummosis). La resina de color mbar se recolecta normalmente a mano una vez seca.Es un polisacrido con cantidades variables de D-galactosa, L-arabinosa, L-ramnosay algunos cidos derivados como elcidoD-glucornico o el 4-O-metil-D-cido glucornico.Se trata de una sustancia de color amarillento a pardo, inflamable aunque con un elevado punto de inflamacin (>250 C), buena solubilidad en agua (aprox. 500 g/l) y con un LD50> 16.000 mg/kg.

Goma GuarThe guar plant is an annual plant known as 'Cyamopsis Tetragonaloba'. The important source of nutrition to human and animals is the legume, it regenerates soil nitrogen and the endosperm of guar seed is an important hydrocolloid widely used across a broad spectrum of industries.

Guar Gum mainly consists of hydrocolloidal polysaccharide with a high molecular weight, which consists of galactopyranose- and mannopyranose- units in glycoside linkage which can be chemically described as galactomannan.Goma Guar

Goma Guar

Tragacanth Gum (Goma tragacanto)Lagoma tragacantoes un polisacrido obtenido por incisin de tallos de varias especies deAstragalus, que se encuentran en regiones montaosas de Turqua,Siria,Irak,IrnyRusia It is collected by hand, then graded, milled, and sifted to remove impurities. Tragacanth gum contains a water-soluble fraction and a water-insoluble fraction and the water-soluble fraction is accounted for 30 to 40% of the total gum.

Astragalus gummifer Labillardiere The water soluble fraction is a highly branched neutral polysaccharide composed of 16-linked D-galactosyl backbones with L-arabinose side chains joined by 12-, 13- and/or 15-linkages. The water-insoluble fraction (~60 to 70%), is tragacanthic acid which is consisted of D-galacturonic acid, D-galactose, L-fucose, D-xylose, L-arabinose and L-rhamnose. It has a (14)-linked -D-galacturonopyranosyl backbone chain with randomly substituted xylosyl branches linked at the 3 position of the galacturonic acid residues.La goma es de color blanco o blanco amarillento muy plido, traslcida y crnea. Se rompe con fractura breve, es inodora y tiene ligero sabor. Cuando se pone en agua, la goma tragacanto se hincha, dando una masa gelatinosa, pero slo se disuelve una pequea porcin.Tragacanth Gum (Goma tragacanto)La formacin de la goma tragacanto es completamente distinta a la de lagoma arbiga, pues la goma exuda inmediatamente despus de herir el rbol y, por tanto, estar preformada en la planta, mientras que lagoma arbigase produce lentamente despus de la herida. Un corte del tallo de la planta muestra que las membranas celulares de la mdula y radios medulares se transforman gradualmente en goma, proceso denominadogomosis. La goma absorbe agua y da lugar a una considerable presin dentro del talloTragacanth Gum (Goma tragacanto)

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amylose

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amylopectin

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cellulose

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Schematic of arrangement of cellulose chains in a microfibril.

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glycogen

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