Produce Degradation Pathways and Prevention

505
0-8493-1902-1/05/$0.00+$1.50
© 2005 by CRC Press

17

Microbial Metabolites

in Fruits and Vegetables

Keith Warriner

Department of Food Science, University of Guelph, Guelph,

Ontario N1G 2W1, Canada

Svetlana Zivanovic

Department of Food Science and Technology,

University of Tennessee, Knoxville, TN

CONTENTS

17.1 Introduction................................................................................................ 506
17.2 Role and Function of Microbial Enzymes Associated with Fruits
and Vegetables ........................................................................................... 507
17.2.1 Superoxide Dismutase, Catalase, and Glutathione .................... 507
17.2.2 Laccasese, Polyphenol Oxidases, and Lipoxygenase ................ 508
17.2.3 Pectinases .................................................................................... 509
17.2.4 Cellulose- and Hemicellulose-Degrading Enzymes................... 510
17.2.5 Starch-Degrading Enzymes ........................................................ 512
17.2.6 Enzyme Transport in Microbes .................................................. 514
17.3 Microbial Effects on Produce Flavor ........................................................ 514
17.3.1 Microbial Metabolites That Enhance Produce Quality.............. 514
17.3.2 Microbial Metabolites and Vegetable Spoilage.......................... 516
17.3.3 Microbial Metabolites and Fruit Spoilage ................................. 517
17.3.4 Antimicrobial Agents from Microorganisms ............................. 518
17.3.4.1 Antibiotics ................................................................. 518
17.3.4.2 Bacteriocins ............................................................... 520
17.3.4.3 Mycotoxins................................................................ 521
17.4 Regulation of Gene Expression in Microbes Associated with Plants ...... 522
17.4.1 Quorum Sensing ......................................................................... 522
17.4.2 Microbial Phytohormones........................................................... 523
17.5 Conclusions................................................................................................ 524
References.............................................................................................................. 524