Konjac Glucomannan Konjac Glucomannan Production, Processing, and Functional Applications Edited by George Srzednicki Chaleeda Borompichaichartkul CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2020 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper International Standard Book Number-13: 978-1-138-36717-3 (Hardback) 978-0-429-42992-7 (ebook) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. 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CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organiza- tions that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identi- fication and explanation without intent to infringe. Library of Congress Cataloging‑in‑Publication Data Names: Srzednicki, G. (George), editor. | Borompichaichartkul, Chaleeda, editor. Title: Konjac glucomannan : production, processing, and functional applications / edited by George Srzednicki, Chaleeda Borompichaichartkul. Description: Boca Raton : CRC Press, [2020] | Includes bibliographical references and index. Identifiers: LCCN 2019060021 (print) | LCCN 2019060022 (ebook) | ISBN 9781138367173 (hardback) | ISBN 9780429429927 (ebook) Subjects: LCSH: Polysaccharides. | Polysaccharides industry. | Konjak. | Amorphophallus. Classification: LCC TP248.65.P64 K66 2020 (print) | LCC TP248.65.P64 (ebook) | DDC 664/.06--dc23 LC record available at https://lccn.loc.gov/2019060021 LC ebook record available at https://lccn.loc.gov/2019060022 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com This book is dedicated to the memory of late Dr. James F. Maxwell (‘’Max’’), one of the most prominent botanists of Thailand and neighbouring countries. Max, a native of New York State, graduated from Ohio State University with a BSc in botany and later with an MSc from the University of Singapore, spent over 40 years in Thailand where he worked as a taxonomist in various universities. I came to know Max during the first Flora Malesiana symposium, which held in Leiden 1989. Our post-conference meeting lasted a brief 20 minutes after which we continued our conversations through letters, faxes and emails for almost the next 30 years and never came face-to-face again. He promised to look out for Amorphophallus species during his field trips and so provided a hugely important contribution to my taxonomic work on this genus over the years. I was pleased to honour him in naming the most spectacular species in Thailand after him, Amorphophallus maxwellii Hett., a discovery by himself. Later he co-authored with me the new species named as A. hemicryptus Hett. & Maxw found in a small island in the Mekong on Cambodian soil. As Max was always in need of photocopies from botanical literature and CDs with mostly female opera singers of long forgotten times, there was a lively exchange of such objects and he sent Amorphophallus tubers for my research collection. His thousands of herbarium specimens collected during his field trips in Thailand, Laos, Cambodia and Myanmar are spread across herbaria in the world, many in the Chiang Mai University herbarium where he held office as curator and from where he roamed the tropical forests. His knowledge of plant ecology in those forests was phenomenal. As a mutual acquaintance, Martin van den Bult (pers. Comm.), joined him in a number of field trips and told me how the high standards of working Max held, which often led to outcries after seeing lesser qualitative work, using such terms as “moron” and “cretin” but always in good spirit (because Max liked to drink a strong local “schnapps”, which he called “Mekong”). His relationship with several Thai botanists was brittle, to say the least but in the long run, many of them and an equally high number of students gained profuse knowledge in the field of botany. I deeply cherish my giant pile of faxes and emails from Max in all their good and sometimes evil spirit. A unique person suddenly left us when Max died on 12 May 2015 of a massive heart attack during forest work. I imagine that dying during field work could have been something he would wish for. A fine obituary has been published in Biotropica 48(1) in 2016. Wilbert Hetterscheid One of the last photographs of Max during his field survey in Rayong Province. Max and Amorphophallus maxwellii Contents Preface ..............................................................................................................................................ix Editors ..............................................................................................................................................xi Contributors .................................................................................................................................xiii 1. Introduction .............................................................................................................................1 Chaleeda Borompichaichartkul and George Srzednicki 2. Botanical Background to Amorphophallus .......................................................................5 Wilbert Hetterscheid, Li Heng, Wang Zhonglang, Orachorn Mekkerdchoo, and Cyrille Claudel 3. Biosynthesis and Decomposition of Konjac Glucomannan ......................................101 Orachorn Mekkerdchoo, Yu Lei, and Zhao Jianrong 4. Field Production of Konjac ...............................................................................................115 Zhang Shenglin, Jiang Xuekuan, and Hadi K. Purwadaria 5. Postharvest Technology of Konjac ..................................................................................161 Rarisara Impaprasert, Zhao Jianrong, George Srzednicki, Yu Lei, and Tao Ruixuan 6. Processing of Konjac Flour ...............................................................................................173 Rarisara Impaprasert, Zhao Jianrong, and George Srzednicki 7. Physico-Chemical Properties of Konjac Glucomannan .............................................189 Patricia Le Bail, Céline Lafarge, and Nathalie Cayot 8. Advances in Drying Technology .....................................................................................209 Lamul Wiset, Nattapol Poomsa-ad, Rarisara Impaprasert, and Chaleeda Borompichaichartkul 9. Konjac Industry in Major Producing Countries ..........................................................223 Zhang Shenglin, Hadi K. Purwadaria, Chaleeda Borompichaichartkul, and Phattanit Tripetch 10. Applications of Konjac Glucomannan in Food and Medicine ..................................255 Chaleeda Borompichaichartkul, Afwa Hayuningtyas, and Phattanit Tripetch viii Contents 11. New Trends in the Konjac Flour Industry .....................................................................265 Chaleeda Borompichaichartkul, Desi Sakawulan, Patthasarun Pruksarojanakul, and Phattanit Tripetch 12. Concluding Remarks .........................................................................................................277 Chaleeda Borompichaichartkul and George Srzednicki Index .............................................................................................................................................279 Preface There are about 200 species of genus Amorphophallus in the Araceae family. Except for about 25 species native to Africa, most of them originate from southern, south-eastern and eastern Asia, northern Australia, or Pacific islands. The underground tubers of several of the Asian species are rich in glucomannan, which is a water-soluble polysaccharide that is considered as a dietary fibre. As such, it resists human digestive enzymes and absorp- tion in the small intestine. Hence, it is used as food or food additives (e.g., thickener or emulsifier), food supplements for weight management, and also in the pharmaceutical and cosmetic industries. Given these properties, it is an important economic raw material. The natural sources of glucomannan besides Amorphophallus include tubers of orchids of genus Orchis, hemicellulose present in the wood of conifers, and some bacterial and yeast cell walls. However, the by far most important commercial source of glucomannan are vari- ous species of the genus Amorphophallus. One of the main species producing glucomannan is Amorphophallus konjac, from which the common name of this crop ‘konjac’ originates. The generic name of this compound is ‘konjac glucomannan’, generally designated by the acronym KGM. China had owned and utilized abundant glucomannan resources as early as 2000 years ago, but until the mid-1980s, the konjac production was limited to plants growing in the wild or planted in gardens in front of the houses. After 1985, with the advancement of science and technology and the development of foreign trade, responding to the increasing konjac flour demand in the international market, people began to recog- nize the potential value of konjac-derived products, and the development and utilization of konjac resources took rapidly off. After nearly 30 years of relentless efforts by konjac researchers, growers, and processors in the konjac industry, China has formed a complete konjac supply chain, and its industrial scale continues to expand. In 2009, konjac flour production from China exceeded that of Japan’s which until then was the number one producer in the world. Japan was the first country to form a complete konjac supply chain. About 1500 years ago, konjac was introduced to Japan from China by Buddhist monks. Although its cultiva- tion and utilization took place later than in China, the konjac industry focusing mainly on the production of jelly-like cake called konnyaku, started in Japan earlier than in China. In Japan, konjac has been traded as a commodity on the market since the fourteenth century. The konjac cultivation evolved from a natural perennial growth to the annual cultivation after the seventeenth century. Since then, konjac has been considered as a food source of national importance, and its cultivation and processing became encour- aged since the nineteenth century. Konjac became one of the main ingredients in Japanese healthy traditional meals in the 1960s. The konjac plantation areas ranked first in the world by the 1970s. By the 1990s, the output of fresh harvested tubers reached 100,000 tonnes and 12,000 tonnes of konjac flour was produced. Although the centre of origin and the production areas of several glucomannan producing species are in Southeast Asian countries, the utilization of konjac is mainly driven by the demand of Chinese and Japanese markets. In the past, it was mainly used to make k onjac cake by harvesting the subterranean tubers, called ‘corms’, in their natural habitat, sun drying them after slicing, and then exporting them to the Chinese market. In the last decade, because of the increased investment in processing equipment from China and Japan, the konjac cultivation and mechanical drying of chips has increased in Southeast Asia. ix