Handbook of Coffee Processing By-Products

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Handbook of Coffee Processing By-Products

Sustainable Applications

Edited by

Charis M. GalanakisResearch & Innovation Department

Galanakis LaboratoriesChania, Greece

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v

Contents

List of Contributers .................................................................................................xiiiPreface ......................................................................................................................xv

CHAPTER 1 State of the Art in Coffee Processing By-Products ................................................................................1Rita C. Alves, Francisca Rodrigues, Maria Antónia Nunes, Ana F. Vinha, M. Beatriz P.P. Oliveira

1.1 Introduction ..................................................................................11.2 Coffee Processing ........................................................................3

1.2.1 The Postharvesting Processing .........................................31.2.2 The Coffee Roast ..............................................................61.2.3 The Coffee Beverage ........................................................8

1.3 Coffee By-Products Composition and Potential Applications ..................................................................91.3.1 Coffee Husks/Pulp ............................................................91.3.2 Immature and Defective Coffee Beans ...........................111.3.3 Silverskin ........................................................................131.3.4 Spent Coffee Grounds ....................................................14

1.4 Legislative Frameworks and Policy Recommendations ............181.5 Conclusions ................................................................................21 References ..................................................................................22

CHAPTER 2 Healthy Components of Coffee Processing By-Products ..............................................................................27Benjamin M. Dorsey, Marjorie A. Jones

2.1 Introduction ................................................................................272.1.1 Spent Coffee Grounds ....................................................28

2.2 Background on Antioxidants ......................................................282.2.1 The Chemical Basis of Oxidation and Reduction:

Movement of Electrons ..................................................282.2.2 Oxidants and Antioxidants and Why we

Need Them .....................................................................292.2.3 How we can Measure Antioxidant Amounts ..................312.2.4 The Types of Antioxidants Found in Coffee

(Under Different Roasting Conditions) and Coffee Processing By-Products ......................................33

2.2.5 Useful Materials in Different Coffee By-Products .........482.2.6 Coffee Pulp and Silver Skin ...........................................49

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2.2.7 Composition Similarities Between Coffee and Coffee Processing By-Products ...............................51

2.3 Conclusions ................................................................................51 References ..................................................................................51

CHAPTER 3 The Biorefinery Concept for the Industrial Valorization of Coffee Processing By-Products ...........63Valentina Aristizábal-Marulanda, Yéssica Chacón-Perez, Carlos A. Cardona Alzate

3.1 Coffee .........................................................................................633.2 Coffee Processing ......................................................................653.3 Coffee Processing By-Products .................................................67

3.3.1 Coffee Silverskin ............................................................683.3.2 Spent Coffee Grounds ....................................................683.3.3 Coffee Pulp .....................................................................683.3.4 Coffee Husk ....................................................................723.3.5 Coffee Cut-Stems ...........................................................72

3.4 Characterization of Coffee Processing By-Products ..................723.5 Possibilities of Integral Valorization of Coffee

Processing By-Products .............................................................733.6 Products Obtained from Coffee Processing By-Products ..........74

3.6.1 Polyphenols ....................................................................743.6.2 Biofuels ..........................................................................773.6.3 Bioenergy .......................................................................783.6.4 Bioproducts ....................................................................783.6.5 Biofertilizers ...................................................................78

3.7 Biorefineries Obtain Bioproducts and Biofuels from SCG and CCS: Case Study ...............................................783.7.1 Small-Scale Versus High-Scale Biorefineries ................793.7.2 Process Description ........................................................803.7.3 Technoeconomic Assessment .........................................833.7.4 Results and Analysis .......................................................84

3.8 Conclusions ................................................................................86 References ..................................................................................86

CHAPTER 4 Extraction and Formulation of Bioactive Compounds ...............................................................................93Ana Belščak-Cvitanovic,́ Draženka Komes

4.1 Introduction ................................................................................934.2 Recovery of Bioactive Constituents of Coffee By-Products ......96

4.2.1 Polyphenolic Compounds ..............................................96

viiContents

4.2.2 Caffeine ........................................................................1054.2.3 Pigments .......................................................................1114.2.4 Lipid Compounds .........................................................112

4.3 Formulation and Design of Coffee Processing By-Products Bioactives ............................................................1194.3.1 Encapsulation as a Formulation Approach of

Coffee By-Products Bioactives ....................................1214.4 Patented and Potential Applications of Recovered

Bioactives .................................................................................1264.5 Conclusions ..............................................................................130 References ................................................................................132

CHAPTER 5 Emerging Technologies for the Recovery of Valuable Compounds from Coffee Processing By-Products .....................................................141Marcelo M.R. de Melo, Armando J.D. Silvestre, Inês Portugal, Carlos M. Silva

5.1 Introduction ..............................................................................1425.2 Separation Technologies ..........................................................147

5.2.1 Solid–Liquid Extraction ...............................................1475.2.2 Supercritical Fluid Extraction ......................................1515.2.3 Subcritical Water Extraction .........................................1555.2.4 Microwave Assisted Extraction ....................................1575.2.5 Ultrasound Assisted Extraction ....................................1585.2.6 Pulsed Electric Field Extraction ...................................1605.2.7 Other Technological Opportunities

for Coffee By-Products Valorization ............................1605.3 Conclusions ..............................................................................163 References ................................................................................164

CHAPTER 6 Applications of Recovered Compounds in Food Products ...................................................................171Maria D. del Castillo, Amaia Iriondo-DeHond, Nuria Martinez-Saez, Beatriz Fernandez-Gomez, Maite Iriondo-DeHond, Jin-Rong Zhou

6.1 Introduction ..............................................................................1716.2 Coffee By-Products as High Value-Added

Sustainable Food Ingredients ...................................................1736.2.1 Nutrients .......................................................................1736.2.2 Bioactive Compounds ..................................................1776.2.3 Additives and Coadjuvants ...........................................180

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6.2.4 Safety Concerns About Coffee By-Products as Food Ingredients ...........................................................182

6.3 Applications in Sustainable and Health-Promoting Beverages .................................................................................1836.3.1 Coffee Husks and Coffee Pulp .....................................1836.3.2 Coffee Silverskin ..........................................................1856.3.3 Spent Coffee Grounds ..................................................186

6.4 Applications in Sustainable and Healthier Foods ....................1866.4.1 Coffee Husks and Coffee Pulp .....................................1866.4.2 Coffee Silverskin ..........................................................1886.4.3 Spent Coffee Grounds ..................................................188

6.5 Future Research .......................................................................1896.6 Conclusions ..............................................................................190 References ................................................................................190

CHAPTER 7 Applications of Recovered Bioactive Compounds in Cosmetics and Other Products .......................................................................195Francisca Rodrigues, Maria Antónia Nunes, Rita C. Alves, M. Beatriz P.P. Oliveira

7.1 Introduction ..............................................................................1957.2 Active Compounds of Coffee Processing

By-Products of Interest for Cosmetic Proposes .......................1987.2.1 Coffee Silverskin ..........................................................1987.2.2 Spent Coffee Grounds ..................................................1997.2.3 Coffee Husks ................................................................2007.2.4 Defective/Immature Coffee Beans ...............................200

7.3 Possible Cosmetic Application of Coffee By-Products ..............................................................................2017.3.1 Protection Against UV Damage ...................................2027.3.2 Anticellulite Activity ....................................................2057.3.3 Emollient Properties .....................................................2067.3.4 Antimicrobial Activity ..................................................2087.3.5 Antiaging Activity ........................................................2097.3.6 Antiinflammatory Activity ...........................................2117.3.7 Other Potential Applications of Coffee

By-Products in Cosmetics ............................................2127.4 Future Perspectives ..................................................................2127.5 Conclusions ..............................................................................213 References ................................................................................214

ixContents

CHAPTER 8 Biotechnological Applications of Coffee Processing By-Products .....................................................221Suzana E. Hikichi, Rafaela P. Andrade, Eustáquio S. Dias, Whasley F. Duarte

8.1 Coffee and its By-Products ......................................................2218.2 Coffee By-Products with Potential

Uses in Fermentation Biotechnology .......................................2238.3 Production of Bioethanol .........................................................2258.4 Production of Aromatic Volatile Compounds, Acids,

Carotenoids, and Polyhydroxyalkanoates ................................2288.4.1 Aromatic Volatile Compounds .....................................2288.4.2 Organic Acids ...............................................................2298.4.3 Carotenoids ...................................................................2318.4.4 Polyhydroxyalkanoates ................................................232

8.5 Mushroom Cultivation on Coffee By-Products .......................2328.5.1 Autoclaved Substrate for Axenic Cultivation ...............2338.5.2 Treatment of Substrate with Lime Solution .................2358.5.3 Short Composting and Steam Pasteurization ...............2368.5.4 General Considerations About the Preparation

of Mushroom Substrates ...............................................2368.5.5 The Mushroom Yield on Coffee-Husk-Based

Substrates .....................................................................2378.6 Enzymes Production from Coffee By-Products as

Substrates .................................................................................2388.7 Conclusions ..............................................................................241 References ................................................................................241

CHAPTER 9 Environmental Applications of Coffee Processing By-Products .....................................................245Mejdi Jeguirim, Lionel Limousy, Madona Labaki

9.1 Introduction ..............................................................................2459.2 The use of Coffee-Processing Residues as Biosorbents

for Pollutants Removal from Aqueous Solution ......................2469.2.1 Application for the Removal of Heavy Metals .............2469.2.2 Application to the Dyes Removal .................................250

9.3 Elaboration of Char from Coffee Processing Residues for Wastewater Treatment ........................................................255

9.4 Synthesis, Characterization and Applications of Activated Carbons ................................................................2579.4.1 Synthesis and Characterization ....................................257

x Contents

9.4.2 Applicants in Aqueous Effluent Treatments .................2679.4.3 Removal of Minerals Present in Water .........................2679.4.4 Removal of Organic Molecules

Present in Water ............................................................2709.4.5 Gas- and Vapor-Phase Adsorption ................................276

9.5 Catalyst Preparation for Pollutants Oxidation (Decomposition) ......................................................................287

9.6 Conclusions ..............................................................................292 References ................................................................................293

CHAPTER 10 The Potential of Pyrolysing Exhausted Coffee Residue for the Production of Biochar ..........................299Wen-Tien Tsai

10.1 Introduction ..............................................................................29910.2 Brief Description of Biomass Conversion into

Biochar by Pyrolysis ................................................................30210.2.1 Composition of Biomass ..............................................30210.2.2 Features of Biomass .....................................................30210.2.3 Pretreatment of Biomass ..............................................30310.2.4 Conversion of Biomass .................................................30310.2.5 Pyrolysis of Biomass ....................................................304

10.3 Biochar Characterization .........................................................30610.3.1 Physical Properties of Biochar .....................................30610.3.2 Chemical Properties of Biochar ...................................308

10.4 Exhausted Coffee Residue and its Reuse as an Energy Source ..........................................................................310

10.5 Pyrolysis for the Production of Biochar from Exhausted Coffee Residue ..............................................313

10.6 Thermochemical Properties of Exhausted Coffee Residue and its Resulting Biochar ...........................................315

10.7 The Potential for Agricultural and Fabric Applications of Biochar Derived from Exhausted Coffee Residue ...............317

10.8 Conclusions ..............................................................................319 References ................................................................................319

CHAPTER 11 Energy Applications of Coffee Processing By-Products ............................................................................323Lionel Limousy, Mejdi Jeguirim, Madona Labaki

11.1 Introduction ..............................................................................32311.1.1 Combustion ..................................................................324

xiContents

11.1.2 Pyrolysis, Torrefaction, Gasification, and Hydrothermal Conversion Processes .....................338

11.1.3 Bioethanol, Biodiesel, and Biogas Production .............35511.2 Conclusions ..............................................................................362 References ................................................................................364

CHAPTER 12 Vermicompost Derived from Spent Coffee Grounds: Assessing the Potential for Enzymatic Bioremediation ......................................................................369Juan C. Sanchez-Hernandez, Jorge Domínguez

12.1 Introduction ..............................................................................37012.2 Multiple Applications of Spent Coffee Grounds:

An Overview ............................................................................37112.3 Environmental Applications of Spent Coffee Grounds ............372

12.3.1 Use of Spent Coffee Grounds in Agriculture ...............37212.3.2 Bioremediation with Spent Coffee Grounds ................373

12.4 Vermicomposted Spent Coffee Grounds: An Environmentally Safe Value-Added Product .....................37512.4.1 Enzyme Activities in Vermicompost from

Spent Coffee Grounds ..................................................37812.4.2 Pesticide Detoxifying Esterases in Vermicompost

from Spent Coffee Grounds .........................................38312.4.3 Potential use of SCG-Vermicompost for Safe

Cultivation in Urban Agriculture ..................................38812.5 Conclusions ..............................................................................391 References ................................................................................392

Index .........................................................................................399

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List of Contributors

Rita C. AlvesREQUIMTE/LAQV, University of Porto, Porto, Portugal

Rafaela P. AndradeUniversity of Lavras (UFLA), Lavras, Minas Gerais, Brazil

Valentina Aristizábal-MarulandaNational University of Colombia, Manizales, Colombia

Ana Belščak-CvitanovićUniversity of Zagreb, Zagreb, Croatia

Carlos A. Cardona AlzateNational University of Colombia, Manizales, Colombia

Yéssica Chacón-PerezNational University of Colombia, Manizales, Colombia

Marcelo M.R. de MeloUniversity of Aveiro, Aveiro, Portugal

Maria D. del CastilloInstitute of Food Science Research (UAM–CSIC), Madrid, Spain

Eustáquio S. DiasUniversity of Lavras (UFLA), Lavras, Minas Gerais, Brazil

Jorge DomínguezUniversity of Vigo, Vigo, Spain

Benjamin M. DorseyIllinois State University, Normal, IL, United States

Whasley F. DuarteUniversity of Lavras (UFLA), Lavras, Minas Gerais, Brazil

Beatriz Fernandez-GomezInstitute of Food Science Research (UAM–CSIC), Madrid, Spain

Suzana E. HikichiUniversity of Lavras (UFLA), Lavras, Minas Gerais, Brazil

Amaia Iriondo-DeHondInstitute of Food Science Research (UAM–CSIC), Madrid, Spain

Maite Iriondo-DeHondMadrid Institute for Research and Rural Development, Agriculture, and Food, Alcalá de Henares, Spain

xiv List of Contributors

Mejdi JeguirimInstitute of Materials Science of Mulhouse, Mulhouse, France

Marjorie A. JonesIllinois State University, Normal, IL, United States

Draženka KomesUniversity of Zagreb, Zagreb, Croatia

Madona LabakiLebanese University, Fanar, Jdeidet, Lebanon

Lionel LimousyInstitute of Materials Science of Mulhouse, Mulhouse, France

Nuria Martinez-SaezInstitute of Food Science Research (UAM–CSIC), Madrid, Spain

Maria Antónia NunesREQUIMTE/LAQV, University of Porto, Porto, Portugal

M. Beatriz P.P. OliveiraREQUIMTE/LAQV, University of Porto, Porto, Portugal

Inês PortugalUniversity of Aveiro, Aveiro, Portugal

Francisca RodriguesREQUIMTE/LAQV, University of Porto, Porto, Portugal

Juan C. Sanchez-HernandezUniversity of Castilla-La Mancha, Toledo, Spain

Carlos M. SilvaUniversity of Aveiro, Aveiro, Portugal

Armando J.D. SilvestreUniversity of Aveiro, Aveiro, Portugal

Wen-Tien TsaiNational Pingtung University of Science and Technology, Pingtung, Taiwan

Ana F. VinhaREQUIMTE/LAQV, University of Porto; University Fernando Pessoa, Porto, Portugal

Jin-Rong ZhouBeth Israel Deaconess Medical Center, Boston, MA, United States

xv

Preface

Coffee is one of the most consumed beverages all over the world and the second largest commodity in trading volume, being surpassed only by oil. Currently, more than 70 countries produce coffee. Global coffee production was estimated to be 145 million 60 kg bags in 2015–16, and consumption rounded the 152.1 million. On the other hand, while billions of cups of coffee are consumed worldwide each day, the bulk of the coffee plant biomass is considered to be waste. Following the several steps of production, the coffee industry generates huge amounts of residues, such as coffee silverskin, spent coffee grounds, coffee pulp, coffee husks, cut coffee stems, and wastewater. For instance, in Brazil the production of coffee in the years 2008–13 averaged 2.9 million tons, generating about 1.4 million tons of waste each year. These residues constitute a source of severe contamination of water bodies and lands around production units, and a serious environmental problem for all the pro-ducing countries. The problem is now getting even worse, taking into consideration the recent concerns that global warming will severely affect coffee cultivation if not make it disappear.

The current state-of-the-art handling of coffee processing residues includes man-agement practices that either degrade the substrate or lead to diminution of their pol-lution load without advancing high-added-value ingredients like antioxidants. These practices have a negative ecologic and economic impact on the coffee industry, and cannot be continued within the sustainability and bioeconomy frame of the years to come. The urgent need for sustainability within the coffee industry has turned the interest of researchers to investigate the handling of coffee by-products with another perspective (e.g., by adapting more profitable options). Therefore, modern coffee industries are driven to develop valorization strategies that allow not only the recov-ery of high-added-value ingredients, but also their recycling through the generation of new products that find applications in diverse biotechnological fields, such as pharmaceutical, food, or cosmetics industries.

Following these considerations, there is a need for a new guide covering the lat-est developments in this particular direction. The current book aims to indicate the alternative sustainable solutions of upgrading coffee processing residues, as well as denoting their industrial potential as a source for the recovery of bioactive com-pounds and their reutilization in the previously noted sectors. It fills the existing gap in the current literature by providing a reference for all the involved partners active in the field trying to optimize the performance of coffee-processing industries and reduce their environmental impact. This is conducted by denoting advantages, disad-vantages, and real potentiality of relevant processes, as well as highlighting success stories that are already applied in some countries. The ultimate goal is to support the scientific community, professionals, and producers that aspire to develop real high-scale commercial applications.

xvi Preface

The book consists of 12 chapters. Chapter 1 discusses the state of the art in the field of coffee processing by-products by describing the steps involved in coffee pro-cessing from the field to the cup, the respective generation of by-products along the chain, and their characteristics. In addition, it provides an overview of the methods proposed for the sustainable management of these by-products, as well as legislative frameworks and policy recommendations. Chapter 2 explores the healthy compo-nents (e.g., caffeine, chlorogenic acids, trigonelline, and diterpenes) of coffee and coffee processing by-products, and gives some background on antioxidants (what they are and how to study them) and how these relate to health. Chapter 3 deals with the industrial valorization of relevant residues within the integrated concept of bio-refinery, taking into account production scale, design, and technical and economic issues. Chapter 4 explores the extraction and formulation of bioactive compounds from coffee processing by-products using conventional extraction techniques and approaches. An overview of patented recovery methodologies and potential applica-tions resulting from the use of the recovered bioactives is provided, too. Chapter 5 discusses the recovery of target compounds using emerging technologies (e.g., super-critical fluids, subcritical water, ultrasound, and microwave-assisted extraction).

The rest of the chapters deal with the sustainable applications of recovered ingredients in different sectors. In particular, Chapter 6 summarizes applications of coffee by-products in food products due to their biological, nutritional, and techno-logical functions. Chapter 7 concentrates on the potential applications of bioactive compounds from coffee processing by-products as active ingredients for skin care products. Their potential UV protective action, emollient capacity, and antiwrinkle and antimicrobial activity are critically reviewed and discussed. Chapters 8 and 9 deal with the biotechnological (e.g., as a substrate for the cultivation of microor-ganisms) and environmental (e.g., generation of activated carbons) applications of coffee processing by-products, respectively. Chapter 10 explores the potential of utilizing exhausted coffee residues as a precursor for the production of biochar and their application for agricultural purposes. Chapter 11 describes the possibilities of using coffee processing by-products for energy applications (e.g., biofuels, biodiesel, and bioethanol). In particular, the recovery of energy from biomass through ther-mochemical processes (e.g., gasification, combustion, hydrothermal treatment) and biochemical processes is presented. Finally, Chapter 12 provides an overview of the main current applications of spent coffee grounds and discusses the results obtained during their processing through vermicomposting on a pilot scale.

Conclusively, the book provides a handbook for agricultural, chemical, and envi-ronmental engineers, as well as food scientists and technologists who work in the coffee-processing industry and are seeking to improve their by-products manage-ment by actively utilizing them in effective applications. It addresses professionals, researchers, specialists, and new product developers working at the edge of the food and environmental sectors. It could be used as a textbook for ancillary reading at the graduate and postgraduate levels, and in multidisciplinary courses dealing with agricultural science, food technology, and environmental, bioresource, and chemical engineering. Along these lines, it could become a target reference for libraries and

xviiPreface

institutes dealing with coffee production all around the world (e.g., Brazil, Vietnam, Colombia, Indonesia, USA).

I would like to take this opportunity to thank all the contributors of this book for their fruitful collaboration and high-quality work in bringing together different topics and sustainable applications in an integral and comprehensive text. Their acceptance of my invitation to participate in this book, as well as their dedication to editorial guidelines and the book’s concept is highly appreciated. In addition, I would also like to thank the acquisitions editor, Megan Ball, and the book manager, Jackie Truesdell, for their assistance during editing, as well as Lisa Jones and all the team of Elsevier during the production process. I would also like to acknowledge the support and expertise of the Food Waste Recovery Group of the ISEKI Food Association that provided us with tools and insights in the field. The ability of the group to support the food and beverage industries in order to recover food waste and improve sustain-ability is remarkable.

Last but not least, a message for the readers: in such big collaborative project, it is impossible to avoid minor errors or gaps. Therefore, if you find any mistakes or have any objections regarding the content of the book, please do not hesitate to contact me. Instructive comments are and always will be welcome.

Charis M. GalanakisResearch & Innovation Department, Galanakis Laboratories, Chania, Greece

e-mail: cgalanakis@chemlab.grFood Waste Recovery Group, ISEKI Food Association, Vienna, Austria

e-mail: foodwasterecoverygroup@gmail.com

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1

CHAPTER

Handbook of Coffee Processing By-Products. http://dx.doi.org/10.1016/B978-0-12-811290-8.00001-3Copyright © 2017 Elsevier Inc. All rights reserved.

Rita C. Alves*, Francisca Rodrigues*, Maria Antónia Nunes*, Ana F. Vinha*,**, M. Beatriz P.P. Oliveira*

*REQUIMTE/LAQV, University of Porto, Porto, Portugal;

**University Fernando Pessoa, Porto, Portugal

ABSTRACTThis chapter describes the steps involved in coffee processing from the field to the cup and the respective generation of by-products along the chain. The chemical com-position of coffee husks, pulp, immature, and defective beans, coffee silverskin, and spent coffee grounds is detailed and methods for the sustainable management of these by-products are addressed, as well as legislative frameworks and policy rec-ommendations. Although coffee by-products have a high potential of application in different fields, more integrated strategies with the involvement of coffee producers, industries, academic institutions, governmental and nongovernmental organizations are still needed to convert coffee by-products into really profitable substrates.Keywords: coffee production; processing; waste; by-products; valorization; innovation; frameworks

1.1 INTRODUCTIONCoffee is one of the most popular beverages all over the world. Behind each hot and tasteful cup of coffee, which can be presented by so many different ways, a real jour-ney is hidden. The genus Coffea, which belongs to the Rubiaceae family, embraces two of the more important plant species of the international coffee trade: Coffea arabica L. and Coffea canephora Pierre, widely known as Arabica and Robusta. C. arabica L., considering the different varieties and cultivated forms, originates about 65%–70% of the world coffee production. Its origin remounts to the moun-tains of Ethiopia (Yemen, AD 850) and it is an autogamic plant (self-fertile) (Alves et al., 2011; Ferrão, 2009). Its cultivation is carried out in regions of moderate tem-perature from tropical and subtropical areas. Some of the C. arabica varieties with higher commercial interest are the typica Cramer, the bourbon (B. Rodr.) Choussy, the caturra K.M.C., the culumnaris Ottotandr. ex Cramer, the mokka Hort. ex Cra-mer, and the xanthocarpa (Caminhoá) Froehner (Ferrão, 2009).

State of the art in coffee processing by-products 1

2 CHAPTER 1 State of the art in coffee processing by-products

Over the years, as the coffee market achieved great importance, an outstanding scientific and technical investment was performed. The preparation of new cultivars, ecologically well adapted, more productive, resistant to pests and diseases, giving origin to a commercial product of high quality, has been one of the fields in which success has been achieved. The selection and improvement of coffee have been fun-damental tools in this process, which implied the use of hybridizations and crossings to assemble as many desirable characteristics as possible. Along this process, coffee plants that were not originally interesting due to the quality of the produced bever-age were used to induce advantageous characteristics. Thus, besides the natural C. arabica varieties with their typical chromossomal and genetic composition, several others also have been emerging as a result of the genetic improvement (e.g., cultivar Catimor, cultivar Sarchimor) or, even, by natural and spontaneous crossing along the time (e.g., cultivar Mundo Novo, cultivar Bourbon-amarelo). Although not pure, their behavior in culture and their final product presents characteristics similar to those of natural Arabicas (Ferrão, 2009).

C. canephora Pierre, in turn, is indigenous from Equatorial African lowland forests from Guinea to Uganda and its cultivation was extended to Asia and South America. It is an allogamic species (self-sterile) that represents about 10%–25% of the worldwide coffee production. The organoleptic characteristics of these coffees are considered inferior to those of Arabica, but they contain higher levels of caf-feine and total soluble solids. Besides, they present higher resistance to diseases, particularly to the coffee leaf rust (Helimeia vastatrix) and coffee berry disease (Colletotrichum kahawae). Also, their roasted seeds produce a “neutral” brew that easily accept the Arabica flavor, and because it is cheaper, C. canephora sp. have been assuming increased interest in international markets. Their applications are es-sentially to increase the body of the beverages (e.g., espresso coffee) and to produce instant coffee (Alves et al., 2011; Ferrão, 2009; Illy and Viani, 2005). We can cite as examples of varieties of this coffee species the laurentii De Wild, the kouillensis Pierre ex De Wild, the ugandae Cramer, and the welwitschii Chev (Ferrão, 2009). A summary of the main differences between Arabica and Robusta coffees is depicted in Table 1.1.

Besides the referenced main species—C. arabica L. and C. canephora Pierre—others can be listed, as C. liberica or C. stenophyla, but they present low economical importance compared to the first two, since from all the commercial coffees that

Table 1.1 Characteristics of Arabica and Robusta Coffees

Arabica Coffee Robusta Coffee

• Superiorcupquality• Moreappreciatedorganolepticcharacteristics• Lowertotalsolublesolidscontent• Morevulnerabletopestsanddiseases

• Smallerbeansize• Usuallycheaper• Doublecaffeinecontent• Higheryieldofextractablesolids• Moreresistanttopestsanddiseases

31.2 Coffee processing

currently circulate in the international market, about 98% correspond to Arabica and Robusta coffees (Ferrão, 2009).

Currently, more than 70 countries produce coffee. In 2015–16, the global coffee production was about 145 million of 60 kg bags, while the consumption rounded the 152.1 million. Brazil is the world’s largest producer of coffee (∼43 million 60 kg bags in 2015), followed by Vietnam (27.5 million 60 kg bags). Colombia and Indonesia are in third and fourth place, respectively (International Coffee Organization, 2016).

Along the several steps of coffee production (from the small producers to the big companies of coffee processing and roasting) a huge amount of residues is generated. For instance, in Brazil the production of coffee from 2008 to 2013 averaged 2.9 mil-lion tons, being generated about 1.4 million tons of wastes each year (Oliveira and Franca, 2015). Considering all the producing countries, coffee wastes and by- products constitute a source of severe contamination and a serious environmental problem. It is very important that coffee industries make an effort to valorize the by-products that result from coffee processing in order to increase the sustainability of the process. Simultaneously to an environmentally friendly approach, this can be seen as an oppor-tunity to increase economical incomes and create new jobs. In fact, the different types of by-products are rich in valuable chemical compounds with potential applications in diverse biotechnological fields, such as pharmaceutical, food, or cosmetic ones.

The next subsections of this chapter detail the different steps of coffee beans processing (from the field to the fork) in order to show the variety of by-products generated in each phase and, subsequently, to highlight the suggested strategies to recover and use those by-products for innovative and useful applications.

1.2 COFFEE PROCESSING1.2.1 THE POSTHARVESTING PROCESSINGThe postharvesting processing aims to separate the seed from the remaining parts of the coffee fruit and guarantee a good preservation of the final product. Moreover, the technique has to be adequate in order to protect coffee from the acquisition of undesirable characteristics during all this process (Ferrão, 2009).

The coffee fruit has five layers of protective material that need to be removed in order to reveal the bean inside. From outside to inside, it is composed by:

1. the skin (epicarp or exocarp), a monocellular layer covered with a waxy substance; when ripe it can be red, yellow, or pink, according to the coffee variety;

2. the pulp (mesocarp), composed by a fleshy pulp and, in ripe fruits, a slimy pectinaceous layer of mucilage;

3. the parchment (endocarp), a thin polysaccharide covering;4. the silverskin (or chaff), a thin tegument that directly coats the seed; and5. two seeds with elliptical form (Farah and Santos, 2015; Instaurator, 2008).

4 CHAPTER 1 State of the art in coffee processing by-products

The high quality of a commercial coffee can only be achieved when all (or almost all) the fruits are harvested in a perfect stage of maturation. However, this highly increases the costs of the process so, in a normal harvest, perfectly mature fruits (that should be the great majority) are usually mixed with some fruits that are excessively mature or, instead, immature (Ferrão, 2009). According to local conditions of the producer country, coffee processing can be performed by different methods (Alves et al., 2011). Each one has its own advantages and disadvantages; therefore it is not possible to select one as the best. It is possible to obtain com-mercial coffees of good quality using all the processes, if well conducted, and the technique selection depends a lot on the local possibilities (e.g., water availability) (Ferrão, 2009).

In the dry processing method, the cherries are dried and then mechanically dehusked. This process is used for most Brazilian, Ethiopian, and Haitian Arabica coffees, and for Robusta coffee in most parts of the world (Alves et al., 2011). In general, in this technique, excessively mature and immature beans are not usu-ally separated from those perfectly mature and, thus, they will all compose the final batch. The fruits are harvested, and disposed in thin layers (5–10 cm) as quickly as possible. This, together with an adequate mixing along the process, should avoid pulp decomposition (due to its high content in water and sugars) that could originate the much-unappreciated “fermented beans” or “black beans.” The drying process can be performed under the sun in yards (natural drying) or in mechanical dryers. The latest are recommended in regions where rain is frequent during the fruit-drying period or to finish the natural drying. During this process, the coffee beans detach from the parchment (endocarp) and after 3–4 weeks, depending on the drying conditions, the fruits are ready to be dehu-sked (moisture

51.2 Coffee processing

FIGURE 1.1 Coffee Processing Steps in the Wet Postharvesting Method

6 CHAPTER 1 State of the art in coffee processing by-products

(mucilage) that coats the endocarp facilitates depulping by reducing the number of broken seeds and the strength to be applied. However, its tendency to retain water and slippery characteristics can impair the following phases. This mucilage, com-posed mainly by pectins, can be eliminated by fermentation, a process that involves a complex group of chemical and biological reactions. In this phase, the coffee stays in rest to allow the enzymatic and other processes to occur naturally, causing the degradation of mucilage. During this process, the temperature often increases, due to the alcoholic fermentation of the pulp sugar remaining, which is favorable to the enzymatic action of pectinases. The ideal time of fermentation is between 24 and 72 h. Otherwise, the color of the beans can be affected (fermented beans). Besides the natural action of pectinases, commercial enzymes or chemical agents can be also added to increase the efficiency of the process. However, it is still not a very common procedure (Ferrão, 2009).

In a third process, called “semidry” or “semiwashed,” concepts of both dry and wet methods are combined. This method consists of washing and selecting the fruits in flotation tanks, followed by depulping, but excluding the fermentation step (Farah and Santos, 2015). Then, the depulped coffee, which contains the mucilage remains, can be directly dried. This process has been used in Central Africa and Brazil, pro-ducing the “natural depulped coffee”. Both, wet- and semiwashed methods require an additional step for parchment removal, an inner membrane that stays adherent to the beans (Alves et al., 2011).

In addition, in the last years, the mucilage elimination by friction (mechanical action), instead of water, has been gaining supporters. Machines and equipments based on this principle have been appearing in the market, allowing the use of a method that simultaneously saves costs and water. In several regions where the dry-method was a tradition due to the water scarcity, these equipments were, indeed, very well accepted. These machines receive directly the fruits from the washing and calibration and, in sequence, remove the pulp, the mucilage, and wash the parchment coffee that is then ready to be dried and processed (Ferrão, 2009).

As previously referenced, along all of these types of processing, several by- products are generated. Just as an example, values described for washed Colombia coffee show that each 100 kg of mature fruits are constituted by 39 kg of pulp, 22 kg of mucilage, and 39 kg of parchment coffee (Ferrão, 2009). Therefore, considering the millions of bags produced in just 1 year, it can be highlighted that the amount of generated residues is extremely high. Fig. 1.2 summarizes the described postharvest-ing techniques and the main by-products generated in each one.

1.2.2 THE COFFEE ROASTThe roasting of raw beans is usually carried out in the consumer countries due to the friability and flavor characteristics of roasted beans, which would not resist the necessary movements of international circulation (Ferrão, 2009).

CoverTitle pageCopyright pageContentsList of ContributorsPrefaceChapter 1 - State of the art in coffee processing by-productsAbstractKeywords1.1 - Introduction1.2 - Coffee processing1.2.1 - The postharvesting processing1.2.2 - The coffee roast1.2.3 - The coffee beverage

1.3 - Coffee by-products composition and potential applications1.3.1 - Coffee husks/pulp1.3.2 - Immature and defective coffee beans1.3.3 - Silverskin1.3.4 - Spent coffee grounds

1.4 - Legislative frameworks and policy recommendations1.5 - ConclusionsAcknowledgmentsReferences

Chapter 2 - Healthy components of coffee processing by-productsAbstractKeywords2.1 - Introduction2.1.1 - Spent coffee grounds

2.2 - Background on antioxidants2.2.1 - The chemical basis of oxidation and reduction: movement of electrons2.2.2 - Oxidants and antioxidants and why we need them2.2.2.1 - Important biological roles of antioxidants2.2.2.2 - Dualistic activities of antioxidants

2.2.3 - How we can measure antioxidant amounts2.2.3.1 - DPPH (2,2-diphenyl-1-picrylhydrazyl) assay2.2.3.2 - ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) assay2.2.3.3 - Thiobarbituric acid reactive substances: assay for lipid peroxidation2.2.3.4 - Two superoxide scavenging assays

2.2.4 - The types of antioxidants found in coffee (under different roasting conditions) and coffee processing by-products2.2.4.1 - Caffeine (1,3,7-trimethylxanthine)2.2.4.2 - Caffeine as an antioxidant2.2.4.3 - Caffeine as an immune modulator2.2.4.4 - Caffeine and its relationship in reducing some diseases2.2.4.5 - Chlorogenic acids and caffeic acid2.2.4.6 - Chlorogenic acids modulate glucose and lipid metabolism2.2.4.7 - Chlorogenic acids and their antiinflammatory activities2.2.4.8 - Maillard reaction products2.2.4.9 - Maillard reaction products in coffee and immune modulating effects2.2.4.10 - Methylglyoxal as an inducer of AGEs2.2.4.11 - Trigonelline, kahweol, and cafestol2.2.4.12 - Diterpenes as antiinflammatory molecules2.2.4.13 - Diterpenes effects on blood lipids

2.2.5 - Useful materials in different coffee by-products2.2.5.1 - Husks

2.2.6 - Coffee pulp and silver skin2.2.6.1 - Coffee pulp2.2.6.2 - Coffee silver skin

2.2.7 - Composition similarities between coffee and coffee processing by-products

2.3 - ConclusionsReferencesFurther Reading

Chapter 3 - The biorefinery concept for the industrial valorization of coffee processing by-productsAbstractKeywords3.1 - Coffee3.2 - Coffee processing3.3 - Coffee processing by-products3.3.1 - Coffee silverskin3.3.2 - Spent coffee grounds3.3.3 - Coffee pulp3.3.4 - Coffee husk3.3.5 - Coffee cut-stems

3.4 - Characterization of coffee processing by-products3.5 - Possibilities of integral valorization of coffee processing by-products3.6 - Products obtained from coffee processing by-products3.6.1 - Polyphenols3.6.2 - Biofuels3.6.3 - Bioenergy3.6.4 - Bioproducts3.6.5 - Biofertilizers

3.7 - Biorefineries obtain bioproducts and biofuels from SCG and CCS: case study3.7.1 - Small-scale versus high-scale biorefineries3.7.2 - Process description3.7.2.1 - Oil extraction3.7.2.2 - Sugars extraction3.7.2.3 - Ethanol3.7.2.4 - Furfural3.7.2.5 - HMF3.7.2.6 - Xylitol

3.7.3 - Technoeconomic assessment3.7.4 - Results and analysis

3.8 - ConclusionsAcknowledgmentReferencesFurther Reading

Chapter 4 - Extraction and formulation of bioactive compoundsAbstractKeywords4.1 - Introduction4.2 - Recovery of bioactive constituents of coffee by-products4.2.1 - Polyphenolic compounds4.2.1.1 - Chlorogenic acids

4.2.2 - Caffeine4.2.2.1 - Application of other conventional extraction techniques for the extraction of polyphenols and caffeine from coffe...

4.2.3 - Pigments4.2.3.1 - Anthocyanins4.2.3.2 - Melanoidins

4.2.4 - Lipid compounds4.2.4.1 - Diterpenes4.2.4.2 - Sterols and tocopherols

4.3 - Formulation and design of coffee processing by-products bioactives4.3.1 - Encapsulation as a formulation approach of coffee by-products bioactives4.3.1.1 - Encapsulation of hydrophilic bioactive compounds4.3.1.2 - Encapsulation of lypophilic bioactive compounds

4.4 - Patented and potential applications of recovered bioactives4.5 - ConclusionsReferencesFurther Reading

Chapter 5 - Emerging technologies for the recovery of valuable compounds from coffee processing by-productsAbstractKeywords5.1 - Introduction5.2 - Separation technologies5.2.1 - Solid–liquid extraction5.2.1.1 - Solid–liquid extraction with conventional solvents5.2.1.2 - Extraction with ionic liquids

5.2.2 - Supercritical fluid extraction5.2.3 - Subcritical water extraction5.2.4 - Microwave assisted extraction5.2.5 - Ultrasound assisted extraction5.2.6 - Pulsed Electric Field Extraction5.2.7 - Other technological opportunities for coffee by-products valorization

5.3 - ConclusionsAcknowledgmentsReferences

Chapter 6 - Applications of recovered compounds in food productsAbstractKeywords6.1 - Introduction6.2 - Coffee by-products as high value-added sustainable food ingredients6.2.1 - Nutrients6.2.2 - Bioactive compounds6.2.3 - Additives and coadjuvants6.2.4 - Safety concerns about coffee by-products as food ingredients

6.3 - Applications in sustainable and health-promoting beverages6.3.1 - Coffee husks and coffee pulp6.3.2 - Coffee silverskin6.3.3 - Spent coffee grounds

6.4 - Applications in sustainable and healthier foods6.4.1 - Coffee husks and coffee pulp6.4.2 - Coffee silverskin6.4.3 - Spent coffee grounds

6.5 - Future research6.6 - ConclusionsAcknowledgmentsReferencesFurther Reading

Chapter 7 - Applications of recovered bioactive compounds in cosmetics and other productsAbstractKeywords7.1 - Introduction7.2 - Active compounds of coffee processing by-products of interest for cosmetic proposes7.2.1 - Coffee silverskin7.2.2 - Spent coffee grounds7.2.3 - Coffee husks7.2.4 - Defective/immature coffee beans

7.3 - Possible cosmetic application of coffee by-products7.3.1 - Protection against UV damage7.3.2 - Anticellulite activity7.3.3 - Emollient properties7.3.4 - Antimicrobial activity7.3.5 - Antiaging activity7.3.6 - Antiinflammatory activity7.3.7 - Other potential applications of coffee by-products in cosmetics

7.4 - Future perspectives7.5 - ConclusionsAcknowledgmentsReferences

Chapter 8 - Biotechnological applications of coffee processing by-productsAbstractKeywords8.1 - Coffee and its by-products8.2 - Coffee by-products with potential uses in fermentation biotechnology8.3 - Production of bioethanol8.4 - Production of aromatic volatile compounds, acids, carotenoids, and polyhydroxyalkanoates8.4.1 - Aromatic volatile compounds8.4.2 - Organic acids8.4.3 - Carotenoids8.4.4 - Polyhydroxyalkanoates

8.5 - Mushroom cultivation on coffee by-products8.5.1 - Autoclaved substrate for axenic cultivation8.5.2 - Treatment of substrate with lime solution8.5.3 - Short composting and steam pasteurization8.5.4 - General considerations about the preparation of mushroom substrates8.5.5 - The mushroom yield on coffee-husk-based substrates

8.6 - Enzymes production from coffee by-products as substrates8.7 - ConclusionsReferences

Chapter 9 - Environmental applications of coffee processing by-productsAbstractKeywords9.1 - Introduction9.2 - The use of coffee-processing residues as biosorbents for pollutants removal from aqueous solution9.2.1 - Application for the removal of heavy metals9.2.1.1 - Coffee bean9.2.1.2 - Coffee husk9.2.1.3 - Coffee ground

9.2.2 - Application to the dyes removal9.2.2.1 - Coffee husk9.2.2.2 - Spent coffee ground9.2.2.3 - Coffee bean

9.3 - Elaboration of char from coffee processing residues for wastewater treatment9.4 - Synthesis, characterization and applications of activated carbons9.4.1 - Synthesis and characterization9.4.1.1 - Production of activated carbons9.4.1.2 - Morphological properties9.4.1.3 - Textural properties9.4.1.4 - Surface chemistry properties

9.4.2 - Applicants in aqueous effluent treatments9.4.3 - Removal of minerals present in water9.4.4 - Removal of organic molecules present in water9.4.4.1 - Adsorption of dyes9.4.4.2 - Adsorption of phenol9.4.4.3 - Adsorption of pharmaceutical products, pesticides, and other micropollutants

9.4.5 - Gas- and vapor-phase adsorption9.4.5.1 - Storage of energy gases9.4.5.2 - Adsorption of volatile organic compounds pollutants9.4.5.3 - Adsorption of acid gases pollutants9.4.5.4 - Adsorption of carbon dioxide from postcombustion

9.5 - Catalyst preparation for pollutants oxidation (decomposition)9.6 - ConclusionsReferences

Chapter 10 - The potential of pyrolysing exhausted coffee residue for the production of biocharAbstractKeywords10.1 - Introduction10.2 - Brief description of biomass conversion into biochar by pyrolysis10.2.1 - Composition of biomass10.2.2 - Features of biomass10.2.3 - Pretreatment of biomass10.2.4 - Conversion of biomass10.2.5 - Pyrolysis of biomass

10.3 - Biochar characterization10.3.1 - Physical properties of biochar10.3.1.1 - Specific surface area, pore volume, and pore size distribution10.3.1.2 - Densities

10.3.2 - Chemical properties of biochar10.3.2.1 - Ultimate analysis (elemental analysis)

10.4 - Exhausted coffee residue and its reuse as an energy source10.5 - Pyrolysis for the production of biochar from exhausted coffee residue10.6 - Thermochemical properties of exhausted coffee residue and its resulting biochar10.7 - The potential for agricultural and fabric applications of biochar derived from exhausted coffee residue10.8 - ConclusionsReferencesFurther Reading

Chapter 11 - Energy applications of coffee processing by-productsAbstractKeywords11.1 - Introduction11.1.1 - Combustion11.1.1.1 - Densification of coffee processing by-products11.1.1.1.1 - Pellets production11.1.1.1.2 - Briquettes and logs production

11.1.1.2 - Combustion of coffee husks11.1.1.3 - Combustion of spent coffee grounds11.1.1.3.1 - Combustion of pellets containing SCG11.1.1.3.2 - Combustion of densified logs containing SCG

11.1.2 - Pyrolysis, torrefaction, gasification, and hydrothermal conversion processes11.1.2.1 - Thermogravimetric analysis11.1.2.2 - Pyrolysis11.1.2.2.1 - Slow pyrolysis of defatted coffee grounds11.1.2.2.2 - Fast pyrolysis of upgraded coffee grounds11.1.2.2.3 - Fast pyrolysis of spent coffee grounds11.1.2.2.4 - Microwave fast pyrolysis of coffee hulls11.1.2.2.5 - Copyrolysis11.1.2.2.6 - Catalytic pyrolysis11.1.2.2.7 - Characteristics of crude oil11.1.2.2.8 - Characteristics of the gaseous products

11.1.2.3 - Torrefaction: application to coffee residue and coffee husk11.1.2.4 - Gasification11.1.2.4.1 - Application to coffee wastes11.1.2.4.2 - Catalytic gasification of coffee wastes11.1.2.4.3 - Cogasification of coffee wastes

11.1.2.5 - Hydrothermal conversion: application to spent coffee grounds

11.1.3 - Bioethanol, biodiesel, and biogas production11.1.3.1 - Production of Bioethanol from Coffee Process Byproducts as Feedstock11.1.3.1.1 - Pretreatment techniques11.1.3.1.2 - Hydrolysis step, saccharification11.1.3.1.3 - Fermentation step and bioethanol production11.1.3.1.4 - Case study

11.1.3.2 - Production of biodiesel from coffee processing residues11.1.3.2.1 - Oil extraction and characterization11.1.3.2.2 - Biodiesel production11.1.3.2.3 - Biodiesel characterization

11.1.3.3 - Production of biogas from coffee production waste11.1.3.3.1 - Feedstock supply and characterization11.1.3.3.2 - Biogas production

11.2 - ConclusionsReferencesFurther Reading

Chapter 12 - Vermicompost derived from spent coffee grounds: assessing the potential for enzymatic bioremediationAbstractKeywords12.1 - Introduction12.2 - Multiple applications of spent coffee grounds: an overview12.3 - Environmental applications of spent coffee grounds12.3.1 - Use of spent coffee grounds in agriculture12.3.2 - Bioremediation with spent coffee grounds

12.4 - Vermicomposted spent coffee grounds: an environmentally safe value-added product12.4.1 - Enzyme activities in vermicompost from spent coffee grounds12.4.2 - Pesticide detoxifying esterases in vermicompost from spent coffee grounds12.4.3 - Potential use of SCG-vermicompost for safe cultivation in urban agriculture

12.5 - ConclusionsAcknowledgmentsReferencesFurther Reading

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