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Pectins and their Manipulation
Food Research International 36 (2003) 643–644 www.elsevier.com/locate/foodres
Book review
Pectins and their Manipulation G.B. Seymour and J.P. Knox, Blackwell Publishing, Oxford UK, £79.00. CRC Press, Boca Raton, FL. ISBN 0-8493-9789-8. The book covers not only the chemical structure, biosynthesis and degradation of the important biopolymers in plants, but also their biophysical properties, their links to other wall components and their cell and development biology. Chapter 1. The chemical structure of pectins. Composition of pectic substances in plants are quite different consisting of more than eight structural elements. The structure of pectins is further influenced by enzymatic and chemical modification reactions during the growth of plants, during the ripening and storage of fruits thereby critically influencing processing of fruits and vegetables. These different structures are explained with plenty of chemical formula and illustrations. Chapter 2. Interactions between pectins and other polymers. Although it appears that a portion of pectin is covalently attached to other polymers in the cell wall, the proportion of the pectin that is linked to other polymer varies from plant to plant. Interaction of pectin with xyloglucan, protein, hemicellulose, extensin protein is not only covalent but also noncovalent interactions. Chapter 3. Biosynthesis of pectins. Pectin is the most structurally complicated polysaccharide in the plant cell wall, for instance, at least 14 distinct enzyme activities are required to synthesize the activated sugar substrates and 58 distinct glycosyl-, methyl- and acetyltransferases are required to synthesize pectin. This chapter reviews subcellular location of pectin synthesis, the nucleotidesugar required for synthesis and its mechanism. A list of all transferases required for the synthesis is provided and progress towards identifying and characterizing these enzymes is summarized. Chapter 4. Biophysical properties of pectins. This chapter reviews the contribution of pectins to the strength and flexibility of plant cell wall. The mechanical properties of biopolymer gels including gel structure, mechanism for gel deformation, single-chain mechanics, junction zones under stress are related. Under the mechanochemistry of the doi:10.1016/S0963-9969(03)00002-4
component chains of pectins, chain conformation, single pectic chains under tension, chain aggregation and the potential formation of junction zone, covalent crosslinks are discussed. Development of texture in fruit and cooked vegetable products is dependent on biophysical properties of pectins. Chapter 5. Cell and developmental biology of pectins. Changes of pectins in plant are discussed. The most popular in situ analytical technique is immunoassay, especially immunofluorometry. Pectincell wall interactions are important aspect in pectin developmental biology. Changes of pectin during cell differentiation and cell adhesion are also important discussion. Chapter 6. Modification and degradation of pectins. Pectin-degrading enzymes derived from microorganisms and plants are listed, and then their role being played during pectin degradation is described. Pectin modification during plant development is reviewed including fruit ripening, adhesion and growth. As a tool, gene slicing and use of mutants are explained. Importance of immunocytrogical studies and genetic work including transgenic plant experiments is emphasized. Chapter 7. Microbial pectinases. Pectinases are classified to glycosyl hydrolases (homo- and hetero-galacturonases), pectate and pectin lyases and carbohydrate esterases. Chapter 8. Commercial pectin preparations are covered under five sections, i.e. production, commercial definitions and standards, general properties, handling advice and uses. The references cited include literature up until 2001; most are quite recent references published after 1990. However, unfortunately, the major part of this book are relating to the behavior of pectins in plant cell, which is not much use for food scientists unless they are heavily involved in processing and storage of fruits and vegetables. Fortunately, Chapter 8 is an exception; the last three sections, especially ‘handling advice’ should be of great use to food processors. Shuryo Nakai Department of Food, Nutrition and Health University of British Columbia 6650 N.W. Marine Drive Vancouver, BC, Canada E-mail address: [email protected]
Book review
Pectins and their Manipulation G.B. Seymour and J.P. Knox, Blackwell Publishing, Oxford UK, £79.00. CRC Press, Boca Raton, FL. ISBN 0-8493-9789-8. The book covers not only the chemical structure, biosynthesis and degradation of the important biopolymers in plants, but also their biophysical properties, their links to other wall components and their cell and development biology. Chapter 1. The chemical structure of pectins. Composition of pectic substances in plants are quite different consisting of more than eight structural elements. The structure of pectins is further influenced by enzymatic and chemical modification reactions during the growth of plants, during the ripening and storage of fruits thereby critically influencing processing of fruits and vegetables. These different structures are explained with plenty of chemical formula and illustrations. Chapter 2. Interactions between pectins and other polymers. Although it appears that a portion of pectin is covalently attached to other polymers in the cell wall, the proportion of the pectin that is linked to other polymer varies from plant to plant. Interaction of pectin with xyloglucan, protein, hemicellulose, extensin protein is not only covalent but also noncovalent interactions. Chapter 3. Biosynthesis of pectins. Pectin is the most structurally complicated polysaccharide in the plant cell wall, for instance, at least 14 distinct enzyme activities are required to synthesize the activated sugar substrates and 58 distinct glycosyl-, methyl- and acetyltransferases are required to synthesize pectin. This chapter reviews subcellular location of pectin synthesis, the nucleotidesugar required for synthesis and its mechanism. A list of all transferases required for the synthesis is provided and progress towards identifying and characterizing these enzymes is summarized. Chapter 4. Biophysical properties of pectins. This chapter reviews the contribution of pectins to the strength and flexibility of plant cell wall. The mechanical properties of biopolymer gels including gel structure, mechanism for gel deformation, single-chain mechanics, junction zones under stress are related. Under the mechanochemistry of the doi:10.1016/S0963-9969(03)00002-4
component chains of pectins, chain conformation, single pectic chains under tension, chain aggregation and the potential formation of junction zone, covalent crosslinks are discussed. Development of texture in fruit and cooked vegetable products is dependent on biophysical properties of pectins. Chapter 5. Cell and developmental biology of pectins. Changes of pectins in plant are discussed. The most popular in situ analytical technique is immunoassay, especially immunofluorometry. Pectincell wall interactions are important aspect in pectin developmental biology. Changes of pectin during cell differentiation and cell adhesion are also important discussion. Chapter 6. Modification and degradation of pectins. Pectin-degrading enzymes derived from microorganisms and plants are listed, and then their role being played during pectin degradation is described. Pectin modification during plant development is reviewed including fruit ripening, adhesion and growth. As a tool, gene slicing and use of mutants are explained. Importance of immunocytrogical studies and genetic work including transgenic plant experiments is emphasized. Chapter 7. Microbial pectinases. Pectinases are classified to glycosyl hydrolases (homo- and hetero-galacturonases), pectate and pectin lyases and carbohydrate esterases. Chapter 8. Commercial pectin preparations are covered under five sections, i.e. production, commercial definitions and standards, general properties, handling advice and uses. The references cited include literature up until 2001; most are quite recent references published after 1990. However, unfortunately, the major part of this book are relating to the behavior of pectins in plant cell, which is not much use for food scientists unless they are heavily involved in processing and storage of fruits and vegetables. Fortunately, Chapter 8 is an exception; the last three sections, especially ‘handling advice’ should be of great use to food processors. Shuryo Nakai Department of Food, Nutrition and Health University of British Columbia 6650 N.W. Marine Drive Vancouver, BC, Canada E-mail address: [email protected]