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Pectin Methyl Esterase (pectin + methyl_esterase)
Selected AbstractsHIGH PRESSURE INACTIVATION OF PECTIN METHYL ESTERASE IN ORANGE JUICE USING COMBINATION TREATMENTSJOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2001S. BASAK ABSTRACT The contribution of several high pressure (HP) processing related factors (pressure level, 300-400 MPa; pressure cycle, 1-3, and pressure-hold time, 30,120 min) on the inactivation of pectin methyl esterase (PME) in single strength (pH 3.7 and 11.4 °Brix) and concentrated (pH 3.5 and 42 °Brix) orange juice was evaluated. A response surface methodology was employed to model the combined effects of factors on the enzyme inactivation. The main effects were described by linear or quadratic functions. For both single strength and concentrated orange juices, the effects of all three main factors and some interactions (pressure level, cycle and holding time) were statistically significant (p<0.05). The dual nature of pressure inactivation of PME (with an instantaneous inactivation due to a pressure pulse, instantaneous pressure fall, and first order rate of inactivation during the pressure hold, yielding D and z values) reported in earlier studies was confirmed. Combination models were developed to predict the residual enzyme activity as influenced by the pressure level, number of pressure cycles and pressure hold time. [source] De-esterification of pectin by alkali, plant and fungal pectinmethylesterases and effect on molecular weightJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2005Janice L Hunter Abstract Commercial high methoxyl pectin was de-esterified using chemical saponification or by pectinmethylesterases. A commercial fungal pectin methyl esterase (PME) (EC 3.1.1.11), free of polygalacturonase, or a citrus Valencia PME was used to de-esterify pectin enzymatically to a targeted degree of esterification. The apparent molecular weight of pectin did not change by extended times of Valencia PME treatment and ranged from 154100 to 183500. Fungal PME-modified pectins had moderately increased apparent molecular weight that ranged from 123900 to 169800. The increase in molecular weight was attributed to aggregation. The molecular weight of pectins that were de-esterified by alkali decreased from about 156200 to 91200. Citrus Valencia or fungal PME modification alters the charge of pectin without loss of high molecular weight. Copyright © 2005 Society of Chemical Industry [source] 2-DE proteomic approach to the Botrytis cinerea secretome induced with different carbon sources and plant-based elicitorsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 12 2010Francisco Javier Fernández-Acero Abstract Botrytis cinerea is a phytopathogenic fungus infecting a number of crops (tomatoes, grapes and strawberries), which has been adopted as a model system in molecular phytopathology. B. cinerea uses a wide variety of infection strategies, which are mediated by a set of genes/proteins called pathogenicity/virulence factors. Many of these factors have been described as secreted proteins, and thus the study of this sub-proteome, the secretome, under changing circumstances can help us to understand the roles of these factors, possibly revealing new loci for the fight against the pathogen. A 2-DE, MALDI TOF/TOF-based approach has been developed to establish the proteins secreted to culture media supplemented with different carbon sources and plant-based elicitors (in this study: glucose, cellulose, starch, pectin and tomato cell walls). Secreted proteins were obtained from the culture media by deoxycholate-trichloroacetic acid/phenol extraction, and 76 spots were identified, yielding 95 positive hits that correspond to 56 unique proteins, including several known virulence factors (i.e. pectin methyl esterases, xylanases and proteases). The observed increases in secretion of proteins with established virulence-related functions indicate that this in vitro -induction/proteome-mining approach is a promising strategy for discovering new pathogenicity factors and dissecting infection mechanisms in a discrete fashion. [source] | ||||||||||