This book was developed from the proceedings of the first North American Tannin Conference held in Port. Angeles, Washington, August 1988. The objective of the conference was to bring together people with a common interest in condensed tannins and to promote interdisciplinary interactions that will lead to a better understanding of these important substances. Anot. her objective was the publicat. ion of this book because there has not been a monograph devoted to the chemistry and significance of tannins for several decades. The book is organized into sections dealing with the biosynthesis, structure, re actions, complexation with other biopolymers, biological significance, and use of tannins as specialty chemicals. The authors made a special attempt to focus on what we don't know as well as to provide a summary of what we do know in an effort to assist in planning future research. Our thanks go to the authors who so kindly contributed chapters and so pa tiently responded to our requests. We also thank Rylee Geboski and the Conference Assist. ance Staff, College of Forestry, Oregon State University, for their assistance in planning and conducting t. he conference, and Julia Wilson, Debbie Wolfe, Helen Coletka, and Nancy Greene of the Southern Forest Experiment Station, Pineville, Louisiana, who typed the chapt. ers. Linda Chalker-Scott was especially helpful in assisting us wit. h editing. Dick Hemingway is indebted t. o the staff of the Alexandria Forest.

This book was developed from the proceedings of the 2nd North American Tan nin Conference held in Houghton, Michigan, June, 1991. The objective of this con ference was to bring together people with a common interest in plant polyphenols and to promote interdisciplinary interactions that will lead to a bet ter understand ing of the importance of these substances. Another objective of this conference was to extend the 'tannin family' by making special efforts to encourage participation by scientists outside the United States, obtain more coverage of the hydrolyzable tannins, and further broaden the scope of coverage from the initial concentration on forestry and forest products. Com parison of the contents of this book with 'Chemistry and Significance of Condensed Tannins' that resulted from the proceedings of the 1st North American Tannin Conference shows the degree that these objectives were met. In developing the second conference, care was taken to assure that this book extends rather than duplicates the coverage of the first conference. Therefore, the two books should be taken together to obtain an up to date coverage of the broad area of chemistry and significance of plant polyphenols. Our thanks go to the authors who so kindly contributed chapters and so pa tiently responded to our requests. We thank the Conference Assistance Staff of Michigan Technological University for their help in planning and conducting the conference.

Tannins are one of the polyphenols group found in plants and are mainly studied because of their structural properties and bioactive behavior. Every year new findings concerning their properties and functions are made, and today concerns are mainly focused on how they can be used efficiently in the wood, food, textile, health, and pharmaceutical industries. Thus, the aim of this book is to present the most updated information on the structural properties of tannins, their food sources and variations, biological properties, and health, among other important issues. In addition, the most recent methods used for their isolation, quantifications, and industrial applications will also be covered.

This concisely written book presents information on types of plant phenolics. The sole focus of this volume is on dietary tannins. It reviews the fact that tannins interact with dietary proteins, carbohydrates, minerals, vitamins, digestive enzymes, and lower nutrient availability. This work reveals that in certain parts of the world, tannins also have been reported as carcinogenic. This literature comprehensively reviews chemistry and plant biochemistry, and methods of extraction. It also explains the harmful and toxic effects and remedies to alleviate dietary tannins. This useful resource is a must for all food scientists, nutritionists, biochemists, and animal scientists throughout the world.

Wood as found in trees and bushes was of primary importance to ancient humans in their struggle to control their environment. Subsequent evolution through the Bronze and Iron Ages up to our present technologically advanced society has hardly diminished the importance of wood. Today, its role as a source of paper products, furniture, building materials, and fuel is still of major significance. Wood consists of a mixture of polymers, often referred to as lignocellulose. The cellulose micro fibrils consist of an immensely strong, linear polymer of glucose. They are associated with smaller, more complex polymers composed of various sugars called hemicelluloses. These polysaccharides are embedded in an amorphous phenylpropane polymer, lignin, creating a remarkably strong com posite structure, the lignocellulosic cell wall. Wood also contains materials that are largely extraneous to this lignocellulosic cell wall. These extracellular substances can range from less than 1070 to about 35% of the dry weight of the wood, but the usual range is 2% -10%. Among these components are the mineral constituents, salts of calcium, potassium, sodium, and other metals, particularly those present in the soil where the tree is growing. Some of the extraneous components of wood are too insoluble to be ex tracted by inert solvents and remain to give extractive-free wood its color; very often these are high-molecular-weight polyphenolics.

Tannins constitute a heterogeneous group of polyphenolic compounds, present in a considerable number of vegetable foods. The term tannin is derived from the properties of these compounds to interact and precipitate macromolecules, such as proteins, make them able to tan animal leather. Subsequently a general definition for tannins emerged, referring them as high molecular weight polyphenols that precipitate protein from solution. The first chapter of this book begins with a discussion on the adsorbent biopolymers from tannin extracts for water treatment. The second chapter presents the influences of sensory and psychosocial factors on the intake of tannin-rich foods and beverages. Chapter three investigates condensed tannins derived from grapes and their antioxidant and antimicrobial activity. Chapter four provides a review of the latest research in the extraction of tannins from grapes and how tannin structure can influence wine astringency. The tannin chemistry diversity and its occurrence in ruminant diets, as well as its beneficial and adverse effects on ruminants will be briefly reviewed in chapter five, and aspects related to oral cavity physiology, saliva production/composition and postingestive effects will be also be referred. The final chapter evaluates milk composition of crossbred dairy goats fed Tifton 85 grass replaced by flemingia.