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Which is the by‐product: caffeine or decaf coffee?

Which is the by‐product: caffeine or decaf coffee? Introduction “Decaffeinated coffee looks something like a man without a soul, a woman without grace, no burning pepper, wine without alcohol. Something to fool the senses, without owning their own inner reality. Coffee is not only asked for taste, but the stimulus of its essential element, the force that caffeine infuses on the nervous system.” Austregésilo de Athayde (1898–1993, a Brazilian Journalist) These words define what coffee means for most coffee lovers: the excitement of caffeine. Without a doubt, caffeine is the most consumed psychoactive substance in the world and estimates are that about 80% of people living in countries with available statistics ingest caffeine (Fredholm et al. ; Fredholm ). The first thought that comes in mind when we think about coffee is the stimulant effect of caffeine. An Ethiopian legend says that the excited behavior of his goats led an Arabian shepherd to discover coffee as a beverage (for a comprehensive history about coffee see Ukers ). Therefore, since the very beginning, caffeine and coffee are synonyms. After coming to Europe, coffee became a “global and social stimulant,” inspiring politicians, poets, and musicians, who met in coffee shops where politics and art were discussed (Mazzafera et al. ; Baumann et al. ; Ukers ). Thus, it is easy to conclude that, as a beverage, coffee exists only because there is a close and direct relationship between social aspects and the stimulus caused by caffeine, the “caffeine‐buzz.” So, what is the reason to decaffeinate coffee? After several years of working with coffee and pursuing a naturally decaffeinated (decaf) coffee plant which might be economically cultivated (Borrell ), I turned to ask myself if economically caffeine is not as important as or perhaps even more important than decaf coffee. Of course, it is not always that science has an economical focus, but in this case economical profit seems to be high on both sides, i.e., the decaf and the caffeine sides. Briefly, I will try to pass on to the reader my point of view of this matter. Sources of Pure Caffeine Main sources of caffeine for human ingestion are coffee ( Coffea arabica and C. canephora ) and tea ( Camellia sinensis ), both prepared as infusions. The first beverage is consumed worldwide and the second consumed in a few but highly populated countries, like China, India, and UK. Other minor contribution comes from maté ( Ilex paraguariensis ), cocoa ( Theobroma cacao ), guaraná ( Paullinia cupana ), and cola ( Cola acuminata ), the consumption of which depends on country or region of the globe. Estimates of global in plant production of caffeine suggest 228,300 tons per year or 625,479 kg per day (Mazzafera et al. ). Potentially, all plants listed above may be used to obtain pure caffeine, but coffee beans are the main source, as a by‐product of the decaffeination process. Ludwig Roselius, the founder of the HAG Company in Germany, reported the first patent for decaffeination in 1905. A search in a patent database may return more than a hundred patents, but nowadays decaffeination is carried out predominantly by three processes, which uses water, organic solvent, and supercritical fluids (Katz ; Ramalakshmi and Raghavan ; Heilmann ). Apparently water is not the best choice to decaffeinate coffee because other important substances can be washed out, but a process known as “Swiss Water Process” avoids this by using in the extraction an extract free of caffeine, which is already saturated with valuable substances removed from the coffee beans in a previous round of extraction. Caffeine is removed from the aqueous extract by passing it through a charcoal bed pre‐exposed to a coffee extract from a first batch of decaffeination or sucrose, also aiming to avoid loss of important substances for the quality of the final product. Methylene chloride is the main organic solvent used to extract caffeine from coffee and although more selective than water, it also removes substances that are important for the formation of quality in the coffee drink (Azevedo et al. ). This problem seems to be solved by using supercritical CO 2 , a process where coffee beans are exposed to liquid CO 2 and high temperatures. This process is highly selective, but with the disadvantage of being costly as the components of the industrial plant have to stand pressures over 150 bar, temperatures around 70°C, demands large amounts of CO 2 , and a recovery system, among other technical aspects. Independent of the decaffeination process, this caffeine is named natural because it is obtained from plant materials. Caffeine can also be chemically synthesized by different procedures using, for example, theophylline, uric acid, and uracil as starting molecules (Bobranski and Synowiedski ; Zajac et al. ). Caffeine synthesis was first reported in 1895 (Fischer and Ach , b ) and most of the known synthesis methods were reported/patented between the 1940s and the 1960s (for a full list see The Merck Index, 12th Ed.; Merck & Co., Inc.: Whitehouse Station, NJ, 1996; 268pp). Nowadays the synthesis of caffeine is inexpensive (Zajac et al. ). Caffeine: Natural or Synthetic? Pure caffeine is mainly used as a component of medicines, cosmetics, food, and cola‐based soft drinks. More recently, caffeine has been used in energetic drinks (Mazzafera et al. ). Except for the reports of the National Coffee Association‐NCA of the USA ( http://www.ncausa.org/ ), there are not to my knowledge any accurate statistics and trend analysis on decaf consumption in other countries. This is easily explained by the fact that U.S. is the biggest decaf consumer in the world (Mazzafera et al. ). On the other hand, NCA reports do not give any information on the U.S. caffeine production and it is not of my knowledge also if there is an estimate for world caffeine production, and in which proportion natural and synthetic caffeine are produced. To understand a little more about the caffeine market I will use Brazilian figures for decaf (Fig. A and B) and caffeine (Fig. ) importation and exportation between 2001 and 2010. For decaf, I will not consider instant coffee because the data are retrieved as “instant coffee, including decaf.” Brazilian imports (A) and exports (B) of unroasted and roasted decaf coffee over 10 years (2001–2010). Source: Secretariat of Foreign Trade (Secretaria do Comércio Exterior) of the Brazilian Ministry of Development, Industry and Foreign Trade (Ministério do Desenvolvimento, Indústria e Comércio Exterior). Brazilian imports and exports of caffeine over 10 years (2001–2010). The inserted table shows the five countries leading each operation. Source: Secretariat of Foreign Trade (Secretaria do Comércio Exterior) of the Brazilian Ministry of Development, Industry and Foreign Trade (Ministério do Desenvolvimento, Indústria e Comércio Exterior). Between 2001 and 2010 Brazil exported 2697 tons of roasted and unroasted decaf coffee (Fig. A), and imported only 83.2 tons as roasted coffee (Fig. B), which confirms that decaf is little drunk in Brazil (Mazzafera et al. ). If we consider that coffee beans have on average 1% of caffeine (Mazzafera ; Ashihara et al. ), these 2697 tons of exported decaf would mean 26.97 tons of extracted caffeine. The Brazilian Association of Coffee Industry estimated that in 2011 the coffee consumption in Brazil reached 19.72 million bags of 60 kg of raw beans, that is, 1,183,000 tons. If Brazilians drink 1% of this coffee as decaf, this might be 11,830 tons. Considering 1% of caffeine in the coffee beans, the resulting production of caffeine from 2011 coffee consumption in Brazil would be 118.3 tons. This number does not match the 10‐year average data of the Brazilian importation (1400.7 tons) and exportation (215 tons) of caffeine (Fig. ) plus the 10‐year average of a potential production of caffeine from decaf exports (2.697 tons) as calculated above. There is more caffeine than Brazil can produce if we consider only coffee decaffeination. Probably, much of this difference comes from decaffeination of guaraná ( P. cupana ), whose seeds may have up to 6% of caffeine depending on the variety (Escobar et al. ; Antonelli‐Ushirobira et al. ). However, Brazil produced 3754 tons of guaraná in 2011 ( http://www.ibge.gov.br/home/estatistica/indicadores/agropecuária ; accessed in Feb, 2012) and even taking 6% of caffeine as a mean value in the seeds and considering that all Brazilian guaraná is decaffeinated, this would yield only 225 tons. One may argue that Guaraná, a popular drink in Brazil based on concentrated guaraná syrup, might use a significant amount of caffeine; however, Brazilian regulations allow only 0.2% syrup supplementation. Thus, it seems obvious that caffeine has other sources, most likely synthetic. Figure shows an insert table showing from which countries Brazil imported caffeine between 2001 and 2010, and China, which does not drink coffee or decaf coffee, is the main supplier. Germans drink decaf coffee and can justify their second place (Mazzafera et al. ). Is There a Fight for Natural Caffeine? Unfortunately again, there is no world statistics available to quantify the use of caffeine as an additive in food, soft drinks, and medicines, but surely pharmaceutical and cola‐drink‐based industries are among the biggest buyers of pure caffeine. There are two other industries raising the market for caffeine that have been neglected, the industry of the so‐called energy drinks or energizers and the cosmetic industry. The word “natural” has been extensively used by different food and cosmetic companies as an appeal to identify their products as healthier. They are made of or they have components from natural sources. The idea is to establish a link between natural products and health. Caffeine has found a difficult way in the market for natural products because the relationship between this alkaloid and health problems has been established for decades, although many of these problems were not scientifically confirmed (James ; Higdon and Frei ). As a consequence, decaf coffee emerged as an alternative product for those worried about possible caffeine effects, other than as a stimulant. But, on the other hand, depending on the product and which public it reaches or it was made for, the story may be different. It is well known in the cosmetic and medical literature that caffeine can protect the skin against UV‐cancer (Abel et al. ) confirming previous research carried out in mice (Lu et al. ). It was recently suggested that this protection was related with inhibition of ataxia telangiectasia and Rad3‐related (ATR) kinase (Kawasumi et al. ), an enzyme that senses DNA damage, activating the DNA damage checkpoint, and consequently leading to cell cycle arrest (Sancar et al. ). In addition, caffeine absorbs light in the UV region and might be used as a sunscreen (Lu et al. ). Caffeine has long been added as an ingredient in creams used for the treatment of cellulite (Bertin et al. ). In fact, it is the commonest ingredient in cellulite creams (Sainio et al. ). The caffeine effect seems to be related to vasoconstriction and glycerol release (Roure et al. ) and some creams may have up to 3% of caffeine (Dias et al. ). These are two examples of how natural and synthetic caffeine can make a difference as more and more in the beauty market try to offer products that are based on natural products. Prognostics for 2014 are that skin care will lead in the beauty market to reach $91 billion (Euromonitor statistics – http://www.gcimagazine.com/marketstrends/segments/skincare/101889763.html ). Another example is the industry for drinks containing natural caffeine, which are preferred because they are generally assumed to be healthier than energizer drinks containing synthetic caffeine (Zhang et al. ). Together, energizer drinks containing caffeine and beauty products can be an enormous market for natural caffeine if the appeal is healthy. As an increased number of people choose natural products because they associated that with health, the origin of caffeine matters for the consumer. Such worry is reflected in the development of methods to discriminate natural and synthetic caffeine (Zhang et al. ). About 4 years ago, a company contacted me to explore the possibility of a coffee plantation aimed to remove caffeine from the leaves, as the market for natural caffeine was increasing while the market for decaf coffee was not maintaining the same pace to attend the demand. Their estimate was that a coffee plant with about 3% of caffeine in the leaves and producing 15 tons of leaves per ha per year would make the plantation profitable. There is not a coffee species containing such caffeine content in the leaves and certainly a revolution would have to be made in terms of how to grow coffee to produce such amount of leaves year after year. But, at least regarding the knowledge of how to produce a coffee plant containing high caffeine levels, the data available and accumulated since the first studies in the 1960s on caffeine metabolism show that it is possible (Kato and Mizuno ; Mazzafera ). Producing a Fortified Coffee Caffeine metabolism has been extensively studied in coffee and tea ( Camellia sinensis ) (Ashihara et al. ). Caffeine synthase genes have been identified in coffee (Kato and Mizuno ) as well as a promoter for a N ‐methyltransferase gene associated with caffeine biosynthesis in Coffea canephora (Satyanarayana et al. ). However, it is important to determine which coffee species is worthwhile to be transformed. A number of reports on coffee genetic transformation have shown how difficult it might be to work with Coffea arabica , the most economically important species, contributing to approximately 70% of the coffee trade in the world (Mazzafera et al. ). Protocols available for C. arabica transformation, most of them using Agrobacterium tumefaciens , are difficult to reproduce and transformation efficiency is usually less than 1% (Ribas et al. , ). Coffea canephora species, which accounts for about 30% of the coffee traded in the world, is more amenable for transformation (Kumar et al. ). There are also other positive aspects of transforming C. canephora to a fortified caffeine plant such as (1) a bigger aerial part than C. arabica , producing therefore more leaves; (2) a higher endogenous content of caffeine in leaves and fruits (Mazzafera et al. ; Silvarolla et al. ); (3) it grows well at a higher temperature and displays good tolerance to drought (DaMatta and Ramalho ); (4) it has tolerance to diseases (Silva et al. ) and pests (Guerreiro Filho ); (5) and has a high productivity and variability that may be used in breeding for beverage quality (Leroy et al. ). The last aspect is very important as this species is known to produce beverage of an inferior quality when compared with C. arabica . Despite all these positive aspects, there would still be a great challenge in using beans and/or leaves to obtain caffeine. There is no report on decaf C. canephora available in the market but although in some countries illicit, C. canephora beans are used in blends with C. arabica beans (Wermelinger et al. ). Therefore, it seems reasonable that beans and leaves might be both used for caffeine extraction, as the market for a decaf C. canephora does not exist. It remains, however, to define the adaptations in agricultural practices to grow this species with such purpose. Some challenges would be the determination of new fertilization levels, adopt strategies for a strong control of leaf pests and diseases, the development of techniques to abolish flowering thus diverting photoassimilates to the leaves, determining the density of the plantation (spacing among rows and plants in the row) and the number of main stems per plant, etc. Although it is feasible to produce a caffeine‐fortified coffee plant, only a profound economical analysis of the natural caffeine market would predict the profitability of the project. Right now, there are no economical elements and information available for such an analysis and in part this is because the little knowledge we have on the caffeine market is naturally kept under seven keys by the companies involved. Acknowledgments I thank Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq‐Brazil) for a research fellowship, and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for supporting my research on caffeine in coffee. I also thank Prof. José Ferreira da Silva and Flávia Schimpl for helping to raise the data of the Brazilian imports and exports of caffeine and decaf coffee. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Food and Energy Security Wiley

Which is the by‐product: caffeine or decaf coffee?

Food and Energy Security , Volume 1 (1) – Jul 1, 2012

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© 2012 John Wiley & Sons Ltd and the Association of Applied Biologists
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2048-3694
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Abstract

Introduction “Decaffeinated coffee looks something like a man without a soul, a woman without grace, no burning pepper, wine without alcohol. Something to fool the senses, without owning their own inner reality. Coffee is not only asked for taste, but the stimulus of its essential element, the force that caffeine infuses on the nervous system.” Austregésilo de Athayde (1898–1993, a Brazilian Journalist) These words define what coffee means for most coffee lovers: the excitement of caffeine. Without a doubt, caffeine is the most consumed psychoactive substance in the world and estimates are that about 80% of people living in countries with available statistics ingest caffeine (Fredholm et al. ; Fredholm ). The first thought that comes in mind when we think about coffee is the stimulant effect of caffeine. An Ethiopian legend says that the excited behavior of his goats led an Arabian shepherd to discover coffee as a beverage (for a comprehensive history about coffee see Ukers ). Therefore, since the very beginning, caffeine and coffee are synonyms. After coming to Europe, coffee became a “global and social stimulant,” inspiring politicians, poets, and musicians, who met in coffee shops where politics and art were discussed (Mazzafera et al. ; Baumann et al. ; Ukers ). Thus, it is easy to conclude that, as a beverage, coffee exists only because there is a close and direct relationship between social aspects and the stimulus caused by caffeine, the “caffeine‐buzz.” So, what is the reason to decaffeinate coffee? After several years of working with coffee and pursuing a naturally decaffeinated (decaf) coffee plant which might be economically cultivated (Borrell ), I turned to ask myself if economically caffeine is not as important as or perhaps even more important than decaf coffee. Of course, it is not always that science has an economical focus, but in this case economical profit seems to be high on both sides, i.e., the decaf and the caffeine sides. Briefly, I will try to pass on to the reader my point of view of this matter. Sources of Pure Caffeine Main sources of caffeine for human ingestion are coffee ( Coffea arabica and C. canephora ) and tea ( Camellia sinensis ), both prepared as infusions. The first beverage is consumed worldwide and the second consumed in a few but highly populated countries, like China, India, and UK. Other minor contribution comes from maté ( Ilex paraguariensis ), cocoa ( Theobroma cacao ), guaraná ( Paullinia cupana ), and cola ( Cola acuminata ), the consumption of which depends on country or region of the globe. Estimates of global in plant production of caffeine suggest 228,300 tons per year or 625,479 kg per day (Mazzafera et al. ). Potentially, all plants listed above may be used to obtain pure caffeine, but coffee beans are the main source, as a by‐product of the decaffeination process. Ludwig Roselius, the founder of the HAG Company in Germany, reported the first patent for decaffeination in 1905. A search in a patent database may return more than a hundred patents, but nowadays decaffeination is carried out predominantly by three processes, which uses water, organic solvent, and supercritical fluids (Katz ; Ramalakshmi and Raghavan ; Heilmann ). Apparently water is not the best choice to decaffeinate coffee because other important substances can be washed out, but a process known as “Swiss Water Process” avoids this by using in the extraction an extract free of caffeine, which is already saturated with valuable substances removed from the coffee beans in a previous round of extraction. Caffeine is removed from the aqueous extract by passing it through a charcoal bed pre‐exposed to a coffee extract from a first batch of decaffeination or sucrose, also aiming to avoid loss of important substances for the quality of the final product. Methylene chloride is the main organic solvent used to extract caffeine from coffee and although more selective than water, it also removes substances that are important for the formation of quality in the coffee drink (Azevedo et al. ). This problem seems to be solved by using supercritical CO 2 , a process where coffee beans are exposed to liquid CO 2 and high temperatures. This process is highly selective, but with the disadvantage of being costly as the components of the industrial plant have to stand pressures over 150 bar, temperatures around 70°C, demands large amounts of CO 2 , and a recovery system, among other technical aspects. Independent of the decaffeination process, this caffeine is named natural because it is obtained from plant materials. Caffeine can also be chemically synthesized by different procedures using, for example, theophylline, uric acid, and uracil as starting molecules (Bobranski and Synowiedski ; Zajac et al. ). Caffeine synthesis was first reported in 1895 (Fischer and Ach , b ) and most of the known synthesis methods were reported/patented between the 1940s and the 1960s (for a full list see The Merck Index, 12th Ed.; Merck & Co., Inc.: Whitehouse Station, NJ, 1996; 268pp). Nowadays the synthesis of caffeine is inexpensive (Zajac et al. ). Caffeine: Natural or Synthetic? Pure caffeine is mainly used as a component of medicines, cosmetics, food, and cola‐based soft drinks. More recently, caffeine has been used in energetic drinks (Mazzafera et al. ). Except for the reports of the National Coffee Association‐NCA of the USA ( http://www.ncausa.org/ ), there are not to my knowledge any accurate statistics and trend analysis on decaf consumption in other countries. This is easily explained by the fact that U.S. is the biggest decaf consumer in the world (Mazzafera et al. ). On the other hand, NCA reports do not give any information on the U.S. caffeine production and it is not of my knowledge also if there is an estimate for world caffeine production, and in which proportion natural and synthetic caffeine are produced. To understand a little more about the caffeine market I will use Brazilian figures for decaf (Fig. A and B) and caffeine (Fig. ) importation and exportation between 2001 and 2010. For decaf, I will not consider instant coffee because the data are retrieved as “instant coffee, including decaf.” Brazilian imports (A) and exports (B) of unroasted and roasted decaf coffee over 10 years (2001–2010). Source: Secretariat of Foreign Trade (Secretaria do Comércio Exterior) of the Brazilian Ministry of Development, Industry and Foreign Trade (Ministério do Desenvolvimento, Indústria e Comércio Exterior). Brazilian imports and exports of caffeine over 10 years (2001–2010). The inserted table shows the five countries leading each operation. Source: Secretariat of Foreign Trade (Secretaria do Comércio Exterior) of the Brazilian Ministry of Development, Industry and Foreign Trade (Ministério do Desenvolvimento, Indústria e Comércio Exterior). Between 2001 and 2010 Brazil exported 2697 tons of roasted and unroasted decaf coffee (Fig. A), and imported only 83.2 tons as roasted coffee (Fig. B), which confirms that decaf is little drunk in Brazil (Mazzafera et al. ). If we consider that coffee beans have on average 1% of caffeine (Mazzafera ; Ashihara et al. ), these 2697 tons of exported decaf would mean 26.97 tons of extracted caffeine. The Brazilian Association of Coffee Industry estimated that in 2011 the coffee consumption in Brazil reached 19.72 million bags of 60 kg of raw beans, that is, 1,183,000 tons. If Brazilians drink 1% of this coffee as decaf, this might be 11,830 tons. Considering 1% of caffeine in the coffee beans, the resulting production of caffeine from 2011 coffee consumption in Brazil would be 118.3 tons. This number does not match the 10‐year average data of the Brazilian importation (1400.7 tons) and exportation (215 tons) of caffeine (Fig. ) plus the 10‐year average of a potential production of caffeine from decaf exports (2.697 tons) as calculated above. There is more caffeine than Brazil can produce if we consider only coffee decaffeination. Probably, much of this difference comes from decaffeination of guaraná ( P. cupana ), whose seeds may have up to 6% of caffeine depending on the variety (Escobar et al. ; Antonelli‐Ushirobira et al. ). However, Brazil produced 3754 tons of guaraná in 2011 ( http://www.ibge.gov.br/home/estatistica/indicadores/agropecuária ; accessed in Feb, 2012) and even taking 6% of caffeine as a mean value in the seeds and considering that all Brazilian guaraná is decaffeinated, this would yield only 225 tons. One may argue that Guaraná, a popular drink in Brazil based on concentrated guaraná syrup, might use a significant amount of caffeine; however, Brazilian regulations allow only 0.2% syrup supplementation. Thus, it seems obvious that caffeine has other sources, most likely synthetic. Figure shows an insert table showing from which countries Brazil imported caffeine between 2001 and 2010, and China, which does not drink coffee or decaf coffee, is the main supplier. Germans drink decaf coffee and can justify their second place (Mazzafera et al. ). Is There a Fight for Natural Caffeine? Unfortunately again, there is no world statistics available to quantify the use of caffeine as an additive in food, soft drinks, and medicines, but surely pharmaceutical and cola‐drink‐based industries are among the biggest buyers of pure caffeine. There are two other industries raising the market for caffeine that have been neglected, the industry of the so‐called energy drinks or energizers and the cosmetic industry. The word “natural” has been extensively used by different food and cosmetic companies as an appeal to identify their products as healthier. They are made of or they have components from natural sources. The idea is to establish a link between natural products and health. Caffeine has found a difficult way in the market for natural products because the relationship between this alkaloid and health problems has been established for decades, although many of these problems were not scientifically confirmed (James ; Higdon and Frei ). As a consequence, decaf coffee emerged as an alternative product for those worried about possible caffeine effects, other than as a stimulant. But, on the other hand, depending on the product and which public it reaches or it was made for, the story may be different. It is well known in the cosmetic and medical literature that caffeine can protect the skin against UV‐cancer (Abel et al. ) confirming previous research carried out in mice (Lu et al. ). It was recently suggested that this protection was related with inhibition of ataxia telangiectasia and Rad3‐related (ATR) kinase (Kawasumi et al. ), an enzyme that senses DNA damage, activating the DNA damage checkpoint, and consequently leading to cell cycle arrest (Sancar et al. ). In addition, caffeine absorbs light in the UV region and might be used as a sunscreen (Lu et al. ). Caffeine has long been added as an ingredient in creams used for the treatment of cellulite (Bertin et al. ). In fact, it is the commonest ingredient in cellulite creams (Sainio et al. ). The caffeine effect seems to be related to vasoconstriction and glycerol release (Roure et al. ) and some creams may have up to 3% of caffeine (Dias et al. ). These are two examples of how natural and synthetic caffeine can make a difference as more and more in the beauty market try to offer products that are based on natural products. Prognostics for 2014 are that skin care will lead in the beauty market to reach $91 billion (Euromonitor statistics – http://www.gcimagazine.com/marketstrends/segments/skincare/101889763.html ). Another example is the industry for drinks containing natural caffeine, which are preferred because they are generally assumed to be healthier than energizer drinks containing synthetic caffeine (Zhang et al. ). Together, energizer drinks containing caffeine and beauty products can be an enormous market for natural caffeine if the appeal is healthy. As an increased number of people choose natural products because they associated that with health, the origin of caffeine matters for the consumer. Such worry is reflected in the development of methods to discriminate natural and synthetic caffeine (Zhang et al. ). About 4 years ago, a company contacted me to explore the possibility of a coffee plantation aimed to remove caffeine from the leaves, as the market for natural caffeine was increasing while the market for decaf coffee was not maintaining the same pace to attend the demand. Their estimate was that a coffee plant with about 3% of caffeine in the leaves and producing 15 tons of leaves per ha per year would make the plantation profitable. There is not a coffee species containing such caffeine content in the leaves and certainly a revolution would have to be made in terms of how to grow coffee to produce such amount of leaves year after year. But, at least regarding the knowledge of how to produce a coffee plant containing high caffeine levels, the data available and accumulated since the first studies in the 1960s on caffeine metabolism show that it is possible (Kato and Mizuno ; Mazzafera ). Producing a Fortified Coffee Caffeine metabolism has been extensively studied in coffee and tea ( Camellia sinensis ) (Ashihara et al. ). Caffeine synthase genes have been identified in coffee (Kato and Mizuno ) as well as a promoter for a N ‐methyltransferase gene associated with caffeine biosynthesis in Coffea canephora (Satyanarayana et al. ). However, it is important to determine which coffee species is worthwhile to be transformed. A number of reports on coffee genetic transformation have shown how difficult it might be to work with Coffea arabica , the most economically important species, contributing to approximately 70% of the coffee trade in the world (Mazzafera et al. ). Protocols available for C. arabica transformation, most of them using Agrobacterium tumefaciens , are difficult to reproduce and transformation efficiency is usually less than 1% (Ribas et al. , ). Coffea canephora species, which accounts for about 30% of the coffee traded in the world, is more amenable for transformation (Kumar et al. ). There are also other positive aspects of transforming C. canephora to a fortified caffeine plant such as (1) a bigger aerial part than C. arabica , producing therefore more leaves; (2) a higher endogenous content of caffeine in leaves and fruits (Mazzafera et al. ; Silvarolla et al. ); (3) it grows well at a higher temperature and displays good tolerance to drought (DaMatta and Ramalho ); (4) it has tolerance to diseases (Silva et al. ) and pests (Guerreiro Filho ); (5) and has a high productivity and variability that may be used in breeding for beverage quality (Leroy et al. ). The last aspect is very important as this species is known to produce beverage of an inferior quality when compared with C. arabica . Despite all these positive aspects, there would still be a great challenge in using beans and/or leaves to obtain caffeine. There is no report on decaf C. canephora available in the market but although in some countries illicit, C. canephora beans are used in blends with C. arabica beans (Wermelinger et al. ). Therefore, it seems reasonable that beans and leaves might be both used for caffeine extraction, as the market for a decaf C. canephora does not exist. It remains, however, to define the adaptations in agricultural practices to grow this species with such purpose. Some challenges would be the determination of new fertilization levels, adopt strategies for a strong control of leaf pests and diseases, the development of techniques to abolish flowering thus diverting photoassimilates to the leaves, determining the density of the plantation (spacing among rows and plants in the row) and the number of main stems per plant, etc. Although it is feasible to produce a caffeine‐fortified coffee plant, only a profound economical analysis of the natural caffeine market would predict the profitability of the project. Right now, there are no economical elements and information available for such an analysis and in part this is because the little knowledge we have on the caffeine market is naturally kept under seven keys by the companies involved. Acknowledgments I thank Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq‐Brazil) for a research fellowship, and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for supporting my research on caffeine in coffee. I also thank Prof. José Ferreira da Silva and Flávia Schimpl for helping to raise the data of the Brazilian imports and exports of caffeine and decaf coffee.

Journal

Food and Energy SecurityWiley

Published: Jul 1, 2012

References