The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
William G. T. Willats - One of the best experts on this subject based on the ideXlab platform.
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An array of possibilities for Pectin.
Carbohydrate Research, 2008Co-Authors: Iben Sørensen, Henriette L. Pedersen, William G. T. WillatsAbstract:Pectins are a major component of plant cell walls and have numerous roles in plant growth and development. Extracted Pectins are widely used as functional food ingredients in products including ice creams, jams, jellies and milk drinks. Although all are based on a galacturonan-rich backbone, Pectins are an immensely diverse family of polysaccharides, the functional properties of which are dictated by their fine structures. Understanding the biological roles of Pectins and optimizing their industrial usage requires a detailed knowledge of their diversity and spatial and temporal distributions, and microarray technology is a promising tool for high throughput Pectin analysis. This article discusses the technical aspects of the production of Pectin microarrays and explores their current and potential future uses in the context of recent work in the field.
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Pectin new insights into an old polymer are starting to gel
Trends in Food Science and Technology, 2006Co-Authors: William G. T. Willats, Paul J Knox, Jorn Dalgaard MikkelsenAbstract:Pectin is a high value functional food ingredient widely used as a gelling agent and stabilizer. It is also an abundant, ubiquitous and multifunctional component of the cell walls of all land plants. Food scientists and plant scientists therefore share a common goal to better understand the structure and functionalities of pectic polymers at the molecular level. The basic properties of Pectin have been known for nearly 200 years, but recently there has been tremendous progress in our understanding of the very complex fine structure of pectic polymers and Pectinolytic enzymes. This has been made possible by synergies between plant and food research and by the application of a range of state-of-the-art techniques including enzymatic fingerprinting, mass spectrometry, NMR, molecular modelling, and monoclonal antibodies. With this increased knowledge comes the prospect of novel applications. Producers are beginning to develop a new generation of sophisticated designer Pectins with specific functionalities. Moreover, the ability to manipulate Pectin in planta would have a major impact on fruit and vegetable quality and processing, as well as on Pectin production.
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Pectin: New insights into an old polymer are starting to gel
Trends in Food Science and Technology, 2006Co-Authors: William G. T. Willats, J. Paul Knox, Jorn Dalgaard MikkelsenAbstract:Pectin is a high value functional food ingredient widely used as a gelling agent and stabilizer. It is also an abundant, ubiquitous and multifunctional component of the cell walls of all land plants. Food scientists and plant scientists therefore share a common goal to better understand the structure and functionalities of pectic polymers at the molecular level. The basic properties of Pectin have been known for nearly 200 years, but recently there has been tremendous progress in our understanding of the very complex fine structure of pectic polymers and Pectinolytic enzymes. This has been made possible by synergies between plant and food research and by the application of a range of state-of-the-art techniques including enzymatic fingerprinting, mass spectrometry, NMR, molecular modelling, and monoclonal antibodies. With this increased knowledge comes the prospect of novel applications. Producers are beginning to develop a new generation of sophisticated designer Pectins with specific functionalities. Moreover, the ability to manipulate Pectin in planta would have a major impact on fruit and vegetable quality and processing, as well as on Pectin production. © 2005 Elsevier Ltd. All rights reserved.
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Pectin: cell biology and prospects for functional analysis
Plant Molecular Biology, 2001Co-Authors: William G. T. Willats, William Mackie, Lesley Mccartney, J. Paul KnoxAbstract:Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides. Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls. This review surveys what is known about the structure and function of these Pectin domains. The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based Pectin-modifying enzymes. Recent developments in analytical techniques and in the generation of anti-Pectin probes have begun to place the structural complexity of Pectin in cell biological and developmental contexts. The in muro de-methyl-esterification of homogalacturonan by Pectin methyl esterases is emerging as a key process for the local modulation of matrix properties. Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain. Current knowledge of biosynthetic enzymes, plant and microbial Pectinases and the interactions of Pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.
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analysis of pectic epitopes recognised by hybridoma and phage display monoclonal antibodies using defined oligosaccharides polysaccharides and enzymatic degradation
Carbohydrate Research, 2000Co-Authors: William G. T. Willats, Jorn Dalgaard Mikkelsen, Hans Christian Buchholt, Gerrit Limberg, Gertjan W M Van Alebeek, Jacques A E Benen, Tove M I E Christensen, Jaap Visser, A G J Voragen, Paul J KnoxAbstract:Abstract The structure of epitopes recognised by anti-Pectin monoclonal antibodies (mAbs) has been investigated using a series of model lime-Pectin samples with defined degrees and patterns of methyl esterification, a range of defined oligogalacturonides and enzymatic degradation of pectic polysaccharides. In immuno-dot-assays, the anti-homogalacturonan (HG) mAbs JIM5 and JIM7 both bound to samples with a wide range of degrees of methyl esterification in preference to fully de-esterified samples. In contrast, the anti-HG phage display mAb PAM1 bound most effectively to fully de-esterified Pectin. In competitive inhibition ELISAs using fully methyl-esterified or fully de-esterified oligogalacturonides with 3–9 galacturonic acid residues, JIM5 bound weakly to a fully de-esterified nonagalacturonide but JIM7 did not bind to any of the oligogalacturonides tested. Therefore, optimal JIM5 and JIM7 binding occurs where specific but undefined methyl-esterification patterns are present on HG domains, although fully de-esterified HG samples contain sub-optimal JIM5 epitopes. The persistence of mAb binding to epitopes in pectic antigens, with 41% blockwise esterification (P41) and 43% random esterification (F43) subject to fragmentation by endo-polygalacturonase II (PG II) and endo-Pectin lyase (PL), was also studied. Time course analysis of PG II digestion of P41 revealed that JIM5 epitopes were rapidly degraded, but a low level of PAM1 and JIM7 epitopes existed even after extensive digestion, indicating that some HG domains were more resistant to cleavage by PG II. The chromatographic separation of fragments produced by the complete digestion of P41 by Pectin lyase indicated that a very restricted population of fragments contained the PAM1 epitope while a (1→4)-β- d -galactan epitope occurring on the side chains of pectic polysaccharides was recovered in a broad range of fractions.
Jorn Dalgaard Mikkelsen - One of the best experts on this subject based on the ideXlab platform.
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Pectin new insights into an old polymer are starting to gel
Trends in Food Science and Technology, 2006Co-Authors: William G. T. Willats, Paul J Knox, Jorn Dalgaard MikkelsenAbstract:Pectin is a high value functional food ingredient widely used as a gelling agent and stabilizer. It is also an abundant, ubiquitous and multifunctional component of the cell walls of all land plants. Food scientists and plant scientists therefore share a common goal to better understand the structure and functionalities of pectic polymers at the molecular level. The basic properties of Pectin have been known for nearly 200 years, but recently there has been tremendous progress in our understanding of the very complex fine structure of pectic polymers and Pectinolytic enzymes. This has been made possible by synergies between plant and food research and by the application of a range of state-of-the-art techniques including enzymatic fingerprinting, mass spectrometry, NMR, molecular modelling, and monoclonal antibodies. With this increased knowledge comes the prospect of novel applications. Producers are beginning to develop a new generation of sophisticated designer Pectins with specific functionalities. Moreover, the ability to manipulate Pectin in planta would have a major impact on fruit and vegetable quality and processing, as well as on Pectin production.
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Pectin: New insights into an old polymer are starting to gel
Trends in Food Science and Technology, 2006Co-Authors: William G. T. Willats, J. Paul Knox, Jorn Dalgaard MikkelsenAbstract:Pectin is a high value functional food ingredient widely used as a gelling agent and stabilizer. It is also an abundant, ubiquitous and multifunctional component of the cell walls of all land plants. Food scientists and plant scientists therefore share a common goal to better understand the structure and functionalities of pectic polymers at the molecular level. The basic properties of Pectin have been known for nearly 200 years, but recently there has been tremendous progress in our understanding of the very complex fine structure of pectic polymers and Pectinolytic enzymes. This has been made possible by synergies between plant and food research and by the application of a range of state-of-the-art techniques including enzymatic fingerprinting, mass spectrometry, NMR, molecular modelling, and monoclonal antibodies. With this increased knowledge comes the prospect of novel applications. Producers are beginning to develop a new generation of sophisticated designer Pectins with specific functionalities. Moreover, the ability to manipulate Pectin in planta would have a major impact on fruit and vegetable quality and processing, as well as on Pectin production. © 2005 Elsevier Ltd. All rights reserved.
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analysis of pectic epitopes recognised by hybridoma and phage display monoclonal antibodies using defined oligosaccharides polysaccharides and enzymatic degradation
Carbohydrate Research, 2000Co-Authors: William G. T. Willats, Jorn Dalgaard Mikkelsen, Hans Christian Buchholt, Gerrit Limberg, Gertjan W M Van Alebeek, Jacques A E Benen, Tove M I E Christensen, Jaap Visser, A G J Voragen, Paul J KnoxAbstract:Abstract The structure of epitopes recognised by anti-Pectin monoclonal antibodies (mAbs) has been investigated using a series of model lime-Pectin samples with defined degrees and patterns of methyl esterification, a range of defined oligogalacturonides and enzymatic degradation of pectic polysaccharides. In immuno-dot-assays, the anti-homogalacturonan (HG) mAbs JIM5 and JIM7 both bound to samples with a wide range of degrees of methyl esterification in preference to fully de-esterified samples. In contrast, the anti-HG phage display mAb PAM1 bound most effectively to fully de-esterified Pectin. In competitive inhibition ELISAs using fully methyl-esterified or fully de-esterified oligogalacturonides with 3–9 galacturonic acid residues, JIM5 bound weakly to a fully de-esterified nonagalacturonide but JIM7 did not bind to any of the oligogalacturonides tested. Therefore, optimal JIM5 and JIM7 binding occurs where specific but undefined methyl-esterification patterns are present on HG domains, although fully de-esterified HG samples contain sub-optimal JIM5 epitopes. The persistence of mAb binding to epitopes in pectic antigens, with 41% blockwise esterification (P41) and 43% random esterification (F43) subject to fragmentation by endo-polygalacturonase II (PG II) and endo-Pectin lyase (PL), was also studied. Time course analysis of PG II digestion of P41 revealed that JIM5 epitopes were rapidly degraded, but a low level of PAM1 and JIM7 epitopes existed even after extensive digestion, indicating that some HG domains were more resistant to cleavage by PG II. The chromatographic separation of fragments produced by the complete digestion of P41 by Pectin lyase indicated that a very restricted population of fragments contained the PAM1 epitope while a (1→4)-β- d -galactan epitope occurring on the side chains of pectic polysaccharides was recovered in a broad range of fractions.
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cell wall antibodies without immunization generation and use of de esterified homogalacturonan block specific antibodies from a naive phage display library
Plant Journal, 1999Co-Authors: William G. T. Willats, Jorn Dalgaard Mikkelsen, Philip M Gilmartin, J P KnoxAbstract:Homogalacturonan (HG) is a multi-functional pectic polysaccharide of primary cell walls involved in calcium cross-linking and gel formation, and the regulation of ionic status and porosity of the cell wall matrix, and is a source of oligosaccharins functioning in development and defence. Phage display monoclonal antibodies with specificity for de-esterified stretches ('blocks') of pectic HG have been isolated from a naive phage display library without the need for immunization of animals or conjugation of an oligosaccharide to protein. These antibodies, designated PAM1 and PAM2, bind specifically to de-esterified and un-substituted HG. Assays with a series of Pectins de-esterified by the action of plant or fungal Pectin methyl esterases indicated that the antibodies were specific to de-esterified blocks resulting from the blockwise action of plant Pectin methyl esterases. Analysis of antibody binding to a series of oligogalacturonides indicated that optimal binding required in the region of 30 de-esterified Gala residues. The recognition of such a large epitope by these antibodies allows the HG block architecture of primary cell walls to be identified and localized for the first time. Furthermore, we have demonstrated that monoclonal antibodies with high specificity and avidity to cell wall epitopes can be generated using a 'single pot' phage display approach.
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Cell wall antibodies without immunization: generation and use of de‐esterified homogalacturonan block‐specific antibodies from a naive phage display library
Plant Journal, 1999Co-Authors: William G. T. Willats, Jorn Dalgaard Mikkelsen, Philip M Gilmartin, J P KnoxAbstract:Homogalacturonan (HG) is a multi-functional pectic polysaccharide of primary cell walls involved in calcium cross-linking and gel formation, and the regulation of ionic status and porosity of the cell wall matrix, and is a source of oligosaccharins functioning in development and defence. Phage display monoclonal antibodies with specificity for de-esterified stretches ('blocks') of pectic HG have been isolated from a naive phage display library without the need for immunization of animals or conjugation of an oligosaccharide to protein. These antibodies, designated PAM1 and PAM2, bind specifically to de-esterified and un-substituted HG. Assays with a series of Pectins de-esterified by the action of plant or fungal Pectin methyl esterases indicated that the antibodies were specific to de-esterified blocks resulting from the blockwise action of plant Pectin methyl esterases. Analysis of antibody binding to a series of oligogalacturonides indicated that optimal binding required in the region of 30 de-esterified Gala residues. The recognition of such a large epitope by these antibodies allows the HG block architecture of primary cell walls to be identified and localized for the first time. Furthermore, we have demonstrated that monoclonal antibodies with high specificity and avidity to cell wall epitopes can be generated using a 'single pot' phage display approach.
Siew Yin Chan - One of the best experts on this subject based on the ideXlab platform.
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Pectin as a rheology modifier: Origin, structure, commercial production and rheology
Carbohydrate Polymers, 2017Co-Authors: Siew Yin Chan, David James Young, Wee Sim Choo, Xian Jun LohAbstract:Pectins are a diverse family of biopolymers with an anionic polysaccharide backbone of α-1,4-linked D-galacturonic acids in common. They have been widely used as emulsifiers, gelling agents, glazing agents, stabilizers, and/or thickeners in food, pharmaceutical, personal care and polymer products. Commercial Pectin is classified as high methoxy Pectin (HMP) with a degree of methylation (DM) >50% and low methoxy Pectin (LMP) with a DM
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Pectin as a rheology modifier: Recent reports on its origin, structure, commercial production and gelling mechanism
RSC Polymer Chemistry Series, 2016Co-Authors: Siew Yin Chan, David James Young, Wee Sim Choo, Xian Jun LohAbstract:© 2016 The Royal Society of Chemistry. Pectins (also known by the singular Pectin) are a diverse family of biopolymers with a complex range of structures. Their common feature is a polysaccharide backbone of 1,4-linked α-d-galacturonic acids. Pectins are derived from dicotyledonous and some monocotyledonous plants and make up one third of the cell wall materials. Pectin has been widely used as a gelling and stabilizing agent in food, as an incipient ingredient in pharmaceuticals, in personal care products and in other polymer products. It is recognized as safe (GRAS) by the United States Food and Drug Administration (FDA). Commercial Pectin is extracted using acids from by-products of the food industry such as citrus peel, apple pomace and sugar beet pulp. There are two types of Pectin: high methoxyl (HM) Pectin with a degree of methylation (DM) > 50% and low methoxyl (LM) Pectin. LM Pectins are usually manufactured from HM Pectins by de-esterification. HM Pectins gel by cross-linking homogalacturonan residues through hydrogen bonds and hydrophobic forces between the methoxyl groups, assisted by a high sugar concentration and low pH. In contrast, LM Pectins gel by forming ionic linkages via calcium bridges between two carboxyl groups from two different chains in close proximity, known as the 'egg-box' model. The viscoelastic behavior of both gels depends on intrinsic and extrinsic factors. Chemical modifications of Pectin such as alkylation, amidation and thiolation have been used to manipulate hydrophilicity, hydrophobicity and adhesion.
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effect of extraction conditions on the yield and chemical properties of Pectin from cocoa husks
Food Chemistry, 2013Co-Authors: Siew Yin Chan, Wee Sim ChooAbstract:Different extraction conditions were applied to investigate the effect of temperature, extraction time and substrate–extractant ratio on Pectin extraction from cocoa husks. Pectin was extracted from cocoa husks using water, citric acid at pH 2.5 or 4.0, or hydrochloric acid at pH 2.5 or 4.0. Temperature, extraction time and substrate–extractant ratio affected the yields, uronic acid contents, degrees of methylation (DM) and degrees of acetylation (DA) of the extracted Pectins using the five extractants differently. The yields and uronic acid contents of the extracted Pectins ranged from 3.38–7.62% to 31.19–65.20%, respectively. The DM and DA of the extracted Pectins ranged from 7.17–57.86% to 1.01–3.48%, respectively. The highest yield of Pectin (7.62%) was obtained using citric acid at pH 2.5 [1:25 (w/v)] at 95 C for 3.0 h. The highest uronic acid content (65.20%) in the Pectin was obtained using water [1:25 (w/v)] at 95 C for 3.0 h.
Xian Jun Loh - One of the best experts on this subject based on the ideXlab platform.
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Pectin as a rheology modifier: Origin, structure, commercial production and rheology
Carbohydrate Polymers, 2017Co-Authors: Siew Yin Chan, David James Young, Wee Sim Choo, Xian Jun LohAbstract:Pectins are a diverse family of biopolymers with an anionic polysaccharide backbone of α-1,4-linked D-galacturonic acids in common. They have been widely used as emulsifiers, gelling agents, glazing agents, stabilizers, and/or thickeners in food, pharmaceutical, personal care and polymer products. Commercial Pectin is classified as high methoxy Pectin (HMP) with a degree of methylation (DM) >50% and low methoxy Pectin (LMP) with a DM
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Pectin as a rheology modifier: Recent reports on its origin, structure, commercial production and gelling mechanism
RSC Polymer Chemistry Series, 2016Co-Authors: Siew Yin Chan, David James Young, Wee Sim Choo, Xian Jun LohAbstract:© 2016 The Royal Society of Chemistry. Pectins (also known by the singular Pectin) are a diverse family of biopolymers with a complex range of structures. Their common feature is a polysaccharide backbone of 1,4-linked α-d-galacturonic acids. Pectins are derived from dicotyledonous and some monocotyledonous plants and make up one third of the cell wall materials. Pectin has been widely used as a gelling and stabilizing agent in food, as an incipient ingredient in pharmaceuticals, in personal care products and in other polymer products. It is recognized as safe (GRAS) by the United States Food and Drug Administration (FDA). Commercial Pectin is extracted using acids from by-products of the food industry such as citrus peel, apple pomace and sugar beet pulp. There are two types of Pectin: high methoxyl (HM) Pectin with a degree of methylation (DM) > 50% and low methoxyl (LM) Pectin. LM Pectins are usually manufactured from HM Pectins by de-esterification. HM Pectins gel by cross-linking homogalacturonan residues through hydrogen bonds and hydrophobic forces between the methoxyl groups, assisted by a high sugar concentration and low pH. In contrast, LM Pectins gel by forming ionic linkages via calcium bridges between two carboxyl groups from two different chains in close proximity, known as the 'egg-box' model. The viscoelastic behavior of both gels depends on intrinsic and extrinsic factors. Chemical modifications of Pectin such as alkylation, amidation and thiolation have been used to manipulate hydrophilicity, hydrophobicity and adhesion.
Wee Sim Choo - One of the best experts on this subject based on the ideXlab platform.
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Pectin as a rheology modifier: Origin, structure, commercial production and rheology
Carbohydrate Polymers, 2017Co-Authors: Siew Yin Chan, David James Young, Wee Sim Choo, Xian Jun LohAbstract:Pectins are a diverse family of biopolymers with an anionic polysaccharide backbone of α-1,4-linked D-galacturonic acids in common. They have been widely used as emulsifiers, gelling agents, glazing agents, stabilizers, and/or thickeners in food, pharmaceutical, personal care and polymer products. Commercial Pectin is classified as high methoxy Pectin (HMP) with a degree of methylation (DM) >50% and low methoxy Pectin (LMP) with a DM
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Pectin as a rheology modifier: Recent reports on its origin, structure, commercial production and gelling mechanism
RSC Polymer Chemistry Series, 2016Co-Authors: Siew Yin Chan, David James Young, Wee Sim Choo, Xian Jun LohAbstract:© 2016 The Royal Society of Chemistry. Pectins (also known by the singular Pectin) are a diverse family of biopolymers with a complex range of structures. Their common feature is a polysaccharide backbone of 1,4-linked α-d-galacturonic acids. Pectins are derived from dicotyledonous and some monocotyledonous plants and make up one third of the cell wall materials. Pectin has been widely used as a gelling and stabilizing agent in food, as an incipient ingredient in pharmaceuticals, in personal care products and in other polymer products. It is recognized as safe (GRAS) by the United States Food and Drug Administration (FDA). Commercial Pectin is extracted using acids from by-products of the food industry such as citrus peel, apple pomace and sugar beet pulp. There are two types of Pectin: high methoxyl (HM) Pectin with a degree of methylation (DM) > 50% and low methoxyl (LM) Pectin. LM Pectins are usually manufactured from HM Pectins by de-esterification. HM Pectins gel by cross-linking homogalacturonan residues through hydrogen bonds and hydrophobic forces between the methoxyl groups, assisted by a high sugar concentration and low pH. In contrast, LM Pectins gel by forming ionic linkages via calcium bridges between two carboxyl groups from two different chains in close proximity, known as the 'egg-box' model. The viscoelastic behavior of both gels depends on intrinsic and extrinsic factors. Chemical modifications of Pectin such as alkylation, amidation and thiolation have been used to manipulate hydrophilicity, hydrophobicity and adhesion.
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effect of extraction conditions on the yield and chemical properties of Pectin from cocoa husks
Food Chemistry, 2013Co-Authors: Siew Yin Chan, Wee Sim ChooAbstract:Different extraction conditions were applied to investigate the effect of temperature, extraction time and substrate–extractant ratio on Pectin extraction from cocoa husks. Pectin was extracted from cocoa husks using water, citric acid at pH 2.5 or 4.0, or hydrochloric acid at pH 2.5 or 4.0. Temperature, extraction time and substrate–extractant ratio affected the yields, uronic acid contents, degrees of methylation (DM) and degrees of acetylation (DA) of the extracted Pectins using the five extractants differently. The yields and uronic acid contents of the extracted Pectins ranged from 3.38–7.62% to 31.19–65.20%, respectively. The DM and DA of the extracted Pectins ranged from 7.17–57.86% to 1.01–3.48%, respectively. The highest yield of Pectin (7.62%) was obtained using citric acid at pH 2.5 [1:25 (w/v)] at 95 C for 3.0 h. The highest uronic acid content (65.20%) in the Pectin was obtained using water [1:25 (w/v)] at 95 C for 3.0 h.
