Handbook of Plant Food Phytochemicals Handbook of Plant Food Phytochemicals Sources, Stability and Extraction Edited by B.K. Tiwari Food and Consumer Technology Department Hollings Faculty Manchester Metropolitan University Old Hall Lane Manchester UK Nigel P. Brunton School of Agriculture and Food Science University College Dublin Dublin Ireland Charles S. Brennan Faculty of Agriculture and Life Sciences Lincoln University Lincoln Canterbury New Zealand A John Wiley & Sons, Ltd., Publication This edition first published 2013 © 2013 by John Wiley & Sons, Ltd Wiley-Blackwell is an imprint of John Wiley & Sons, formed by the merger of Wiley’s global Scientific, Technical and Medical business with Blackwell Publishing. 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Library of Congress Cataloging-in-Publication Data Handbook of plant food phytochemicals : sources, stability and extraction / edited by Brijesh Tiwari, Nigel Brunton, Charles S. Brennan. p. cm. Includes bibliographical references and index. ISBN 978-1-4443-3810-2 (hardback : alk. paper) – ISBN 978-1-118-46467-0 (epdf) – ISBN 978-1-118-46469-4 (emobi) – ISBN 978-1-118-46468-7 (epub) – ISBN 978-1-118-46471-7 (obook) 1. Phytochemicals. 2. Plants–Composition. 3. Food–Composition. 4. Food industry and trade. I. Tiwari, Brijesh K. II. Brunton, Nigel. III. Brennan, Charles S. QK861.H34 2012 580–dc23 2012024779 A catalogue record for this book is available from the British Library. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Cover image credits, left to right: © iStockphoto.com/KevinDyer; © iStockphoto.com/aluxum; © iStockphoto.com/FotografiaBasica Cover design by Meaden Creative Set in 10/12pt Times by SPi Publisher Services, Pondicherry, India 1 2013 Contents Contributor list xiii 1 Plant food phytochemicals 1 B.K. Tiwari, Nigel P. Brunton and Charles S. Brennan 1.1 Importance of phytochemicals 1 1.2 Book objective 2 1.3 Book structure 2 PART I CHEMISTRY AND HEALTH 5 2 Chemistry and classification of phytochemicals 7 Rocio Campos-Vega and B. Dave Oomah 2.1 Introduction 7 2.2 Classification of phytochemicals 8 2.2.1 Terpenes 8 2.2.2 Polyphenols 13 2.2.3 Carotenoids 15 2.2.4 Glucosinolates 15 2.2.5 Dietary fiber (non starch polysaccharides) 16 2.2.6 Lectins 17 2.2.7 Other phytochemicals 18 2.3 Chemical properties of phytochemicals 21 2.3.1 Terpenes 21 2.3.2 Polyphenols 22 2.3.3 Carotenoids 23 2.3.4 Glucosinolates 24 2.3.5 Dietary fiber (non starch polysaccharides) 26 2.3.6 Lectins 26 2.3.7 Other phytochemicals 28 2.4 Biochemical pathways of important phytochemicals 34 2.4.1 Shikimate pathway 34 2.4.2 Isoprenoid pathway 37 2.4.3 Polyketide pathway 38 2.4.4 Secondary transformation 40 2.4.5 Glucosinolate biosynthesis 40 References 41 3 Phytochemicals and health 49 Ian T. Johnson 3.1 Introduction 49 vi Contents 3.2 Bioavailability of phytochemicals 50 3.2.1 Terpenes 51 3.2.2 Polyphenols 52 3.2.3 Carotenoids 53 3.2.4 Glucosinolates 54 3.2.5 Lectins 55 3.3 Phytochemicals and their health-promoting effects 55 3.3.1 Phytochemicals as antioxidants 56 3.3.2 Blocking and suppressing the growth of tumours 59 3.3.3 Modifying cardiovascular physiology 62 3.4 General conclusions 63 References 64 4 Pharmacology of phytochemicals 68 José M. Matés 4.1 Introduction 68 4.2 Medicinal properties of phytochemicals 69 4.2.1 Therapeutic use of antioxidants 73 4.2.2 Phytochemicals as therapeutic agents 75 4.3 Phytochemicals and disease prevention 78 4.3.1 Pharmacologic effects of phytochemicals 80 4.4 Phytochemicals and cardiovascular disease 82 4.5 Phytochemicals and cancer 88 4.6 Summary and conclusions 95 References 96 PART II SOURCES OF PHYTOCHEMICALS 105 5 Fruit and vegetables 107 Uma Tiwari and Enda Cummins 5.1 Introduction 107 5.2 Polyphenols 107 5.3 Carotenoids 113 5.4 Glucosinolates 117 5.4.1 Variations in glucosinolates 119 5.5 Glycoalkaloids 120 5.6 Polyacetylenes 121 5.7 Sesquiterpene lactones 123 5.8 Coumarins 124 5.9 Terpenoids 125 5.10 Betalains 125 5.11 Vitamin E or tocols content in fruit and vegetables 126 5.12 Conclusions 129 References 129 6 Food grains 138 Sanaa Ragaee, Tamer Gamel, Koushik Seethraman, and El-Sayed M. Abdel-Aal 6.1 Introduction 138 Contents vii 6.2 Phytochemicals in cereal grains 139 6.2.1 Dietary fiber 139 6.2.2 Phenolic compounds 141 6.2.3 Other phytochemicals 143 6.3 Phytochemicals in legume grains 144 6.3.1 Dietary fiber 144 6.3.2 Phenolic acids 145 6.3.3 Isoflavones 146 6.3.4 Saponins 146 6.3.5 Anthocyanins 147 6.3.6 Lignans 148 6.3.7 Other phytochemicals 148 6.4 Stability of phytochemicals during processing 149 6.5 Food applications and impact on health 152 6.6 Cereal-based functional foods 152 6.7 Legume-based functional foods 153 References 154 7 Plantation crops and tree nuts: composition, phytochemicals and health benefits 163 Narpinder Singh and Amritpal Kaur 7.1 Introduction 163 7.2 Composition 165 7.3 Phytochemicals content 167 7.4 Health benefits 174 References 175 8 Food processing by-products 180 Anil Kumar Anal 8.1 Introduction 180 8.2 Phytochemicals from food by-products 181 8.2.1 Biowaste from tropical fruit and vegetables 181 8.2.2 Citrus peels and seeds 181 8.2.3 Mango peels and kernels 182 8.2.4 Passion fruit seed and rind 183 8.2.5 Pomegranate peels, rinds and seeds 184 8.2.6 Mangosteen rind and seeds 184 8.3 By-products from fruit and vegetables 187 8.3.1 Apple pomace 187 8.3.2 By-products from grapes 187 8.3.3 Banana peels 188 8.3.4 Tomato 188 8.3.5 Carrot 188 8.3.6 Mulberry leaves 189 8.4 Tuber crops and cereals 189 8.4.1 Cassava 189 8.4.2 Defatted rice bran 189 8.5 Extraction of bioactive compounds from plant food by-products 190 viii Contents 8.6 Future trends 190 References 192 PART III IMPACT OF PROCESSING ON PHYTOCHEMICALS 199 9 On farm and fresh produce management 201 Kim Reilly 9.1 Introduction 201 9.2 Pre-harvest factors affecting phytochemical content 202 9.2.1 Tissue type and developmental stage 208 9.2.2 Fertilizer application – nitrogen, phosphorus, potassium, sulphur and selenium 210 9.2.3 Seasonal and environmental effects – light and temperature 212 9.2.4 Biotic and abiotic stress 214 9.2.5 Means of production – organic and conventional agriculture 216 9.2.6 Other factors 217 9.3 Harvest and post-harvest management practices 218 9.3.1 Harvest and post-harvest management of onion 218 9.3.2 Harvest and post-harvest management of broccoli 220 9.3.3 Harvest and post-harvest management of carrot 221 9.4 Future prospects 222 9.4.1 Growing bio-fortified crops – optimized agronomic and post-harvest practices 222 9.4.2 Edible sprouts 222 9.4.3 Variety screening and plant breeding for bio-fortified crops 223 9.4.4 Novel uses for crops and crop wastes 224 References 225 10 Minimal processing of leafy vegetables 235 Rod Jones and Bruce Tomkins 10.1 Introduction 235 10.2 Minimally processed products 236 10.3 Cutting and shredding 237 10.4 Wounding physiology 238 10.5 Browning in lettuce leaves 240 10.6 Refrigerated storage 241 10.7 Modified atmosphere storage 242 10.8 Conclusions 243 References 244 11 Thermal processing 247 Nigel P. Brunton 11.1 Introduction 247 11.2 Blanching 248 11.3 Sous vide processing 250 11.4 Pasteurisation 251 Contents ix 11.5 Sterilisation 254 11.6 Frying 255 11.7 Conclusion 257 References 257 12 Effect of novel thermal processing on phytochemicals 260 Bhupinder Kaur, Fazilah Ariffin, Rajeev Bhat, and Alias A. Karim 12.1 Introduction 260 12.2 An overview of different processing methods for fruits and vegetables 261 12.3 Novel thermal processing methods 261 12.4 Effect of novel processing methods on phytochemicals 264 12.4.1 Ohmic heating 265 12.4.2 Microwave heating 266 12.4.3 Radio frequency 268 12.5 Challenges and prospects/future outlook 268 12.6 Conclusion 269 References 269 13 Non thermal processing 273 B.K. Tiwari, PJ Cullen, Charles S. Brennan and Colm P. O’Donnell 13.1 Introduction 273 13.2 Irradiation 273 13.2.1 Ionising radiation 274 13.2.2 Non ionising radiation 274 13.3 High pressure processing 281 13.4 Pulsed electric field 284 13.5 Ozone processing 286 13.6 Ultrasound processing 289 13.7 Supercritical carbon dioxide 291 13.8 Conclusions 292 References 293 PART IV STABILITY OF PHYTOCHEMICALS 301 14 Stability of phytochemicals during grain processing 303 Laura Alvarez-Jubete and Uma Tiwari 14.1 Introduction 303 14.2 Germination 304 14.3 Milling 307 14.4 Fermentation 312 14.5 Baking 315 14.6 Roasting 323 14.7 Extrusion cooking 324 14.8 Parboiling 327 14.9 Conclusions 327 References 327 x Contents 15 Factors affecting phytochemical stability 332 Jun Yang, Xiangjiu He, and Dongjun Zhao 15.1 Introduction 332 15.2 Effect of pH 335 15.3 Concentration 337 15.4 Processing 338 15.4.1 Processing temperature 338 15.4.2 Processing type 341 15.5 Enzymes 346 15.6 Structure 349 15.7 Copigments 350 15.8 Matrix 353 15.8.1 Presence of SO 353 2 15.8.2 Presence of ascorbic acids and other organic acids 354 15.8.3 Presence of metallic ions 355 15.8.4 Others 356 15.9 Storage conditions 357 15.9.1 Light 357 15.9.2 Temperature 358 15.9.3 Relative humidity (RH) 360 15.9.4 Water activity (a ) 361 w 15.9.5 Atmosphere 361 15.10 Conclusion 363 References 364 16 Stability of phytochemicals at the point of sale 375 Pradeep Singh Negi 16.1 Introduction 375 16.2 Stability of phytochemicals during storage 375 16.2.1 Effect of water activity 376 16.2.2 Effect of temperature 376 16.2.3 Effect of light and oxidation 379 16.2.4 Effect of pH 381 16.3 Food application and stability of phytochemicals 381 16.4 Edible coatings for enhancement of phytochemical stability 382 16.5 Modified atmosphere storage for enhanced phytochemical stability 383 16.6 Bioactive packaging and micro encapsulation for enhanced phytochemical stability 384 16.7 Conclusions 387 References 387 PART V ANALYSIS AND APPLICATION 397 17 Conventional extraction techniques for phytochemicals 399 Niamh Harbourne, Eunice Marete, Jean Christophe Jacquier and Dolores O’Riordan 17.1 Introduction 399 17.2 Theory and principles of extraction 399 Contents xi 17.2.1 Conventional extraction methods 400 17.2.2 Factors affecting extraction methods 401 17.2.3 Limitations of extraction techniques 404 17.3 Examples of conventional techniques 405 17.3.1 Roots 405 17.3.2 Leaves and stems 405 17.3.3 Flowers 407 17.3.4 Fruits 407 17.4 Conclusion 409 References 409 18 Novel extraction techniques for phytochemicals 412 Hilde H. Wijngaard, Olivera Trifunovic and Peter Bongers 18.1 Introduction 412 18.2 Pressurised solvents 413 18.2.1 Supercritical fluid extraction 413 18.2.2 Pressurised liquid extraction (PLE) 419 18.3 Enzyme assisted extraction 421 18.4 Non-thermal processing assisted extraction 423 18.4.1 Ultrasound 423 18.4.2 Pulsed electric fields 424 18.5 Challenges and future of novel extraction techniques 426 References 428 19 Analytical techniques for phytochemicals 434 Rong Tsao and Hongyan Li 19.1 Introduction 434 19.2 Sample preparation 436 19.2.1 Extraction 436 19.2.2 Sample clean-up 438 19.3 Non-chromatographic spectrophotometric methods 439 19.3.1 Total phenolic content (TPC) 440 19.3.2 Total flavonoid content (TFC) 440 19.3.3 Total anthocyanin content (TAC) 441 19.3.4 Total carotenoid content (TCC) 441 19.3.5 Methods based on fluorescence 441 19.3.6 Colorimetric methods for other phytochemicals 442 19.4 Chromatographic methods 442 19.4.1 Conventional chromatographic methods 442 19.4.2 Instrumental chromatographic methods 443 References 447 20 Antioxidant activity of phytochemicals 452 Ankit Patras, Yvonne V. Yuan, Helena Soares Costa and Ana Sanches-Silva 20.1 Introduction 452 20.2 Measurement of antioxidant activity 453 20.2.1 Assays involving a biological substrate 453