Produce Degradation Pathways and Prevention

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0-8493-1902-1/05/$0.00+$1.50
© 2005 by CRC Press

19

Structure and Function of

Complex Carbohydrates

in Produce and Their

Degradation Process

Syed Imam, Justin Shey, Delilah Wood,

Greg Glenn, Bor-Sen Chiou, Maria Inglesby,

Charles Ludvik, Artur Klamczynski,

and William Orts

Bioproduct Chemistry & Engineering Research,

Western Regional Research Center, ARS-USDA, Albany, CA

CONTENTS

19.1 Introduction................................................................................................ 564
19.2 Chemistry, Functional Properties, and Reaction Mechanisms
of Plant Carbohydrates .............................................................................. 565
19.2.1 Starch .......................................................................................... 565
19.2.2 Cellulose...................................................................................... 570
19.2.3 Hemicellulose, Pectin, and Other Interacting Cell
Wall Polymers ............................................................................. 572
19.2.3.1 Pectins ....................................................................... 574
19.3 Molecular Mechanisms of Carbohydrate Degradation Mediated
by Enzymes and Microbes ........................................................................ 576
19.3.1 Starch Depolymerases ................................................................ 577
19.3.2 Cellulose Depolymerases............................................................ 578
19.3.3 Pectin-Degrading Enzymes......................................................... 579
19.4 Biochemical and Structural Changes in Produce in Response to
Postharvest Stresses and Its Relationship to Carbohydrate Polymers...... 580
19.5 Strategies to Minimize Postharvest Damage to Carbohydrates................ 585
References.............................................................................................................. 587