Shape and Size of Pectinic Acid Molecules Deduced from Viscometric Measurements

Owens, H. S.; Lotzkar, H.; Schultz, Thomas; Maclay, W. D.

doi:10.1021/ja01212a079

Cited by 96 publications

(21 citation statements)

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“…A maior parte da pectina usada pela indústria de alimentos é originária dessas matérias-primas, sendo extraída em condições levemente ácidas e em alta temperatura, resultando primariamente em cadeias de homogalacturonana [4] . Pesquisas com fontes convencionais cada sendo que as análises de raios-X concordavam com essa hipótese, mas indicavam ser mais lógica a comparação com a celulose [11] . De acordo com Meyer e Mark (1930 apud Baker), os ácidos pectínicos apresentam grupos metiléster ligados em α(1→4) [12] e a fórmula básica foi estabelecida por Schneider e Bock, em 1937 [13] .…”

Section: Fontesunclassified

“…Sendo uma molécula com regiões de diferente polaridade, os efeitos de carga são consideráveis. A massa molar calculada a partir dos dados de viscosidade intrínseca é provavelmente imprecisa por vários fatores, possíveis de interferir na tensão superficial como hidratação, flexibilidade da molécula e heterogeneidade [11] . A massa molar média é calculada por meio de medidas de viscosidade.…”

Section: Agradecimentosunclassified

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Pectina: da matéria-prima ao produto final

Canteri

Moreno²,

Wosiacki³

et al. 2012

Polímeros

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A pectina, provavelmente a mais complexa macromolécula natural, é um heteropolissacarídeo contendo predominantemente resíduos de ácido galacturônico. Este polímero, do grupo das fibras dietéticas, é amplamente utilizado como geleificante e estabilizante na indústria de alimentos. O principal processo industrial para obtenção de pectina está baseado na solubilização da protopectina do bagaço de maçã e casca de frutos cítricos, realizada em condições levemente ácidas sob aquecimento. Estudos recentes têm reportado a extração de pectina de novas matérias-primas sob diferentes condições, com influência sobre a qualidade e sobre o rendimento do produto final, para aumentar sua qualidade reológica. Esta revisão descreve a estrutura, as fontes, as aplicações, o processo de extração industrial assim como as principais técnicas de caracterização da pectina.

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Section: Fontesunclassified

Section: Agradecimentosunclassified

Pectina: da matéria-prima ao produto final

Canteri

Moreno²,

Wosiacki³

et al. 2012

Polímeros

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“…All three subfractions D eluted as a single, broad, polydisperse peak (Fig 2). In the course of ripening, there was an overall change from larger to smaller polymers, the apparent viscosity-average molecular weights (using the relation of Owens et al 27 ) being reduced by approximately a half between ripe and soft fruits: 6.8, 5.4 and 3.3 kDa for the ripe, overripe and soft fruits respectively (Table 4). These results indicated that the homogalacturonan regions of subfraction D underwent extensive degradation during ripening, in agreement with previous suggestions to explain the loss of material during the dialysis step.…”

Section: Results and Discussion Composition Of Cdta-soluble Pectinsmentioning

confidence: 99%

Changes in the pectic fraction of bush butter (Dacryodes edulis (G Don) HJ Lam) fruit pulp during ripening

Missang

Renard²,

Baron³

et al. 2001

J Sci Food Agric

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CDTA-soluble polysaccharides were extracted from cell wall material (prepared as alcoholinsoluble solids) of bush butter fruit endocarp tissue at three stages of ripeness. The amount of soluble pectins remained constant but they underwent a gradual depolymerisation during ripening. The CDTA extracts were fractionated by anion exchange and the subfractions were analysed for their sugar composition and molecular weight distribution. For all degrees of ripeness the extracts were composed of three minor peaks and two major peaks. The minor peaks appeared to be composed of xyloglucan and mannan-type polymers for the ®rst peak and arabinogalactan-type polymers for the other two peaks. The two main peaks were retained on the column. The ®rst was exclusively composed of homogalacturonan polymers and the second contained principally highly branched rhamnogalacturonan polymers. During ripening, both homogalacturonan and rhamnogalacturonan populations were modi®ed. Modi®cations in the rhamnogalacturonan fraction were principally marked by the accumulation of low-molecular-weight rhamnoglacturonan polymers in the course of ripening.

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“…The eluate was continuously monitored using the automated m-hydroxydiphenyl (34) and orcinol (35) assays on an Alliance instruments (Méry/Oise, France) autoanalyzer. The system was calibrated with pectins for which molecular weights were determined by viscosimetric measurements using a reported relation (36).…”

Section: High-performance Size-exclusion Chromatography (Hpsec)mentioning

confidence: 99%

Pectin from Passion Fruit Fiber and Its Modification by Pectinmethylesterase

Contreras-Esquivel¹,

Aguilar²,

Montañez³

et al. 2010

JFN

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Passion fruit fiber pectin gels represent a new alternative pectin source with potential for food and non-food applications on a commercial scale. Pectic polysaccharides were extracted from passion fruit (Passiflora edulis) fiber using citric acid as a clean catalyst and autoclaved for 20 to 60 min at 121 o C. The best condition of pectin yield with the highest molecular weight was obtained with 1.0% of citric acid (250 mg/g dry passion fruit fiber pectin) for 20 min of autoclaving. Spectroscopic analyses by Fourier transform infrared, enzymatic degradation reactions, and ion-exchange chromatography assays showed that passion fruit pectin extracted for 20 min was homogeneous high methoxylated pectin (70%). Gel permeation analysis confirmed that the pectin extract obtained by autoclaving by 20 min showed higher molecular weights than those autoclaved for 40 and 60 min. Passion fruit pectin extracted for 20 min was enzymatically modified with fungal pectinmethylesterase to create restructured gels. Short autoclave treatment (20 min) with citric acid as extractant resulted in a significant increase of gel strength, improving pectin extraction in terms of functionality. The treatment of solubilized material (pectic polysaccharides) in the presence of insoluble material (cellulose and hemicellulose) with pectinmethylesterase and calcium led to the creation of a stiffer passion fruit fiber pectin gel, while syneresis was not observed.

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Shape and Size of Pectinic Acid Molecules Deduced from Viscometric Measurements

Abstract: Vol. 68 g. of tartronic acid and made up to 50 ml. with water.

Cited by 96 publications

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Pectina: da matéria-prima ao produto final

Pectina: da matéria-prima ao produto final

Changes in the pectic fraction of bush butter (Dacryodes edulis (G Don) HJ Lam) fruit pulp during ripening

Pectin from Passion Fruit Fiber and Its Modification by Pectinmethylesterase

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