Plasticized pectin-based gel electrolytes

Pectin is a natural polymer present in plants and, as all natural polymers has biodegradation properties. Chemically, pectin is a polysaccharide composed of a linear chain of 1 -> 4 linked galacturonic acids, which is esterified with methanol at 80%. The pectin-based gel electrolytes in a transparent film form were obtained by a plasticization process with glycerol and addition of LiClO(4). The films showed good ionic conductivity results, which increased from 10(-5) S/cm for the samples with 37 wt.% of glycerol to 4.7 x 10(-4) S/cm at room temperature for the sample with 68 wt.% of glycerol. The electrochemical behaviors of the samples were studied by electrochemical impedance spectroscopy (EIS), and Nyquist graphs are showed and discussed. The obtained pectin-based samples also presented good adherence to the glass, flexibility, homogeneity (SEM) and transparency (about 70% in the vis) properties. They are good candidates to be applied as gel electrolytes in electrochromic devices. (C) 2009 Elsevier Ltd. All rights reserved.

Preparation and characterization of free films of high amylose/pectin mixtures cross-linked with sodium trimetaphosphate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chitosan-pectin multiparticulate systems associated with enteric polymers for colonic drug delivery

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Physical properties of pectin-high amylose starch mixtures cross-linked with sodium trimetaphosphate

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Studies on productivity and characterization of polygalacturonase from Aspergillus giganteus submerged culture using citrus pectin and orange waste

Polygalacturonases are part of the group of enzymes involved in pectin degradation. The aim of this work was to investigate some of the factors affecting polygalacturonase production by an Aspergillus giganteus strain and to characterize this pectinolytic activity. Several carbon sources, both pure substances and natural substrates, were tested in standing cultures, and the best results were obtained with orange bagasse and purified citrus pectin. on citrus pectin as sole carbon source, the highest extracellular activity (9.5 U/ml and 40.6 U/mg protein) was obtained in 4.5-day-old cultures shaken at 120 rpm, pH 3.5 and 30 degrees C, while on orange bagasse, the highest extracellular activity (48.5 U/ml and 78.3 U/mg protein) was obtained in 3.5-day-old cultures shaken at 120 rpm, pH 6.0 and 30 degrees C. Optimal polygalacturonase activity was observed in assays conducted at pH 5.5-6.5 and 55-60 degrees C. The activity showed good thermal stability, with half-lives of 90 and 30 min when incubated at 55 and 60 degrees C, respectively. High stability was observed from pH 4.5 to 8.5; more than 90% of the activity remained after 24 h in this pH range.

Pectin methylesterase activity and ascorbic acid content from guava fruit, cv. Predilecta, in different phases of development

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Singlet Oxygen Generation Enhanced by Silver-Pectin Nanoparticles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Activity of pectinmethylesterase, pectin content and vitamin C in acerola fruit at various stages of fruit development

In order to know which stage of fruit development is better for acerola industrialization, we studied the PME specific activity, pectin content and vitamin C at various stages of development. The acerola fruits were classified according to colour and weight in five stages: immature green (2.62-3.21 g), green (4.04-4.83 g), mature green/yellow (5.03-5.88 g), pale-red (6.16-6.77 g) and ripe mature (6.92-8.37 g). The results showed that the highest content of pectin and vitamin C occurred at the immature green stage, 4.51 +/- 0.1% yield, 2424 mg/100 g of pulp and decreased as fruit ripened, 2.99 +/- 0.03% yield, 957 +/- 0.0 mg/100 g of pulp, respectively. However, at the same stages, the values of PME specific activity were lowest, 0.61 +/- 0.01 and 0.55 +/- 0.0 units g(-1)/g of pulp, respectively. The highest value of PME activity was 2.08 +/- 0.01 units g(-1)/g of pulp in the green stage. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Production of low methoxyl pectin using immobilized pectin methylesterase silica from acerola (Malpighia glabra L.)

The aim of this work was to develop an efficient reactor for the production of low methoxyl pectin, using pectinmethylesterase (PME, EC 3.1.1.11) from acerola immobilized on silica. The immobilized enzyme was used in up to 50 successive bioconversion runs at 50 degrees C with an efficiency loss of less than 20%. The fixed-bed reactor (6.0 x 1.5 cm) was prepared using PME immobilized in glutaraldehyde-activated silica operated at 50 degrees C with an optimum flow rate of 10 mL h(-1). The bioconversion yield was shown to strongly depend on the nature of the enzymatic preparation. An efficiency of 44% was achieved when concentrated PME was used, compared with only 30% with purified PME, both after an 8-h run. The process described could provide the basis for the development of a commercial-scale process. (c) 2006 Society of Chemical Industry.

Partial purification and characterization of pectin methylesterase from acerola (Malpighia glabra L.)

The enzyme pectin methylesterase (PME) is present in acerola fruit and was partially purified by gel filtration on Sephadex G-100. The results of gel filtration showed different PME isoforms. The total PME (precipitated by 70% salt saturation) and one of these isoforms (fraction from Sephadex G-100 elution) that showed a molecular mass of 15.5 +/- 1.0 kDa were studied. The optimum pH values of both forms were 9.0. The total and the partially purified PME showed that PME specific activity increases with temperature, the total acerola PME retained 13.5% of its specific activity after 90 min of incubation at 98 degreesC. The partially purified acerola (PME isoform) showed 125.5% of its specific activity after 90 min of incubation at 98 degreesC. The K-m values of the total PME and the partially purified PME isoform were 0.081 and 0.12 mg/mL, respectively. The V-max values of the total PME and the partially purified PME were 2.92 and 6.21 mumol/min/mL/mg of protein, respectively.

Acerola's pectin methylesterase: studies of heat inactivation

The effect of temperature on the activity of acerola's pectin methylesterase (PME) was studied to determine its heat-inactivation. The acerola's pectin methylesterase (PME; EC: 3.1.1.11) is very stable at 50 degrees C (10% loss of activity in 100 min) and needed 110 min for its inactivation at 98 degrees C. These values are much higher than the ones required for inactivation of the citrus PME, that has been reported as being equal to 1 min at 90 degrees C. Heat-inactivation of PME was shown to be nonlinear, suggesting the presence of fractions of PME with differing heat-stabilities. The times to inactive the enzyme at 98, 102 and 106 degrees C were 110, 10 and 2.17 min, respectively. The Z value (the rise in temperature necessary to observe a ten times faster heat-inactivation) was 4.71 degrees C. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Gelatin-immobilized pectinmethylesterase for production of low methoxyl pectin

The optimum conditions for the production of low methoxyl pectin using pectinmethylesterase (PME) from acerola (Malpighia glabra L.), immobilized in gelatin, have been established by factorial design and response surface methodology. In the case of the free enzymes the optimum conditions for activity, within ranges adequate for food processing, are low NaCl concentrations (0.10 M), relatively high temperatures (55 degreesC) and slightly basic pH values (pH = 9). The temperature and pH seem to have strong influence on the observed activity. In the immobilized enzyme, optimum NaCl concentration was 0.15 M, while the optimum pH remained at 9.0. (C) 2003 Elsevier Ltd. All fights reserved.

Partial purification and characterization of pectin methylesterase from orange (Citrus sinensis) cv. Pera-rio

The enzyme pectin methylesterase (PME) from orange was extracted and partially purified by filtration on Sephadex G-100. The extraction buffer for orange PME was borate-acetate containing 0.4 M NaCl. Orange PME showed optimum pH at 8.0 and optimum temperature at 50C. The PME enzyme was completely inactivated after 1 min of incubation at 90C. The specific activity increased in the presence of 0.15 M NaCl or 0.025 M Na2SO4, 0.10 M KCl, 0.025 M K2SO4, 0.05 and 0.1 M NH4Cl. Lithium chloride and Li(2)SO(4)inhibited the enzymatic activity at all concentrations studied. The K-m and V(max)value of PME were 0.36 mg/mL and 5.26 mu mol/mL-mg protein, respectively.

Purification and characterization of pectin methylesterase from acerola (Malpighia glabra L.)

The enzyme pectinmethylesterase (PME) from acerola was extracted and purified by gel anion-exchange chromatography (Q Sepharose) and filtration on Sephadex G-100. The results showed two different PME isoforms (PME1 and PME2), with molecular masses of 25.10 and 5.20 kDa, respectively. PMEI specific activity increased by 9.63% after 60 min incubation at 98 degrees C, while PME2 retained 66% of its specific activity under the same conditions. The K-m values of PMEI, PME2 and concentrated PME were 0.94, 0.08 and 0.08mg mL(-1), respectively. The V-max value of PMEI, PME2 and concentrated were 204.08, 2, 158.73 and 2.92 mu mol min(-1) mg(-1) protein, respectively. (c) 2007 Society of Chemical Industry.

Pectin lyase from Aspergillus giganteus: Comparative study of productivity of submerged fermentation on citrus pectin and orange waste

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)