Coffea charrieriana

Last updated

Coffea charrieriana
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Gentianales
Family: Rubiaceae
Genus: Coffea
Species:
C. charrieriana
Binomial name
Coffea charrieriana
Stoff. & F.Anthony

Coffea charrieriana, also known as Charrier coffee , is a species of flowering plant from the Coffea genus. It is a caffeine-free coffee plant endemic to Cameroon in Central Africa. It is the first recorded caffeine-free Coffea in Central Africa, and the second to be recorded in Africa. [2] The first caffeine-free species was previously discovered in Kenya, named C. pseudozanguebariae. [3] The International Institute for Species Exploration at Arizona State University and a committee of taxonomists and scientists voted C. charrieriana as one of the top 10 species described in 2008. [4]

Contents

Taxonomy

Coffea charrieriana is classified under the Rubiaceae family and the genus of Coffea. They are currently 120 species of Coffea spread in tropical Africa and Asia, of which two, Coffea arabica and Coffea canephora , dominate worldwide coffee plant production, making up 99% of produce. [2]

Distribution and habitat

This plant is endemic to West Cameroon in the Bakossi Forest Reserve. It grows in a habitat of wet rainforest on rocky slopes of an altitude of 160m [2] and a mean elevation range of 300m. It is highly threatened by deforestation for logging and palm oil production in its vulnerable lowland forest habitat. [5]

History

Coffea charrieriana was discovered in 2008 and the findings were published in a paper named "A new caffeine-free coffee from Cameroon" to the Botanical Journal of the Linnean Society . [2] The plant was named by authors of the paper, Piet Stoffelen and Francois Anthony, in honour of Professor A. Charrier who had made significant efforts towards the coffee industry. His work included leading the coffee breeding research and collection at Institute Research for Development (IRD) for the last 30 years of the 20th century. He also held a position at the French Office of Genetic Resources (BRG) from 1988 to 1993. He is currently working as the director of research at National Institute for Agricultural Research (INRA), focusing on plant genetics and breeding. [2]

As a result of collaboration between the Institute of Research for Development (IRD), Biodiversity International, Paris Museum of Natural History and the French Agricultural Research Centre from 1966 to 1987, coffee plants from Madagascar, Comoros, Mascarene Islands, Guinea, Ivory Coast, Cameroon, Central Africa, Congo, Ethiopia, Kenya and Tanzania were collected. The cuttings from C. charrieriana were first collected in 1985 from Bakossi Forest Reserve in Cameroon in Central Africa along with 70 other Coffea species, many of which were already taxonomically identified. [6] Though C. charrieriana was identified as morphologically different to previously identified Coffea species, further work was not done until 1997. In 1997 the cuttings were sent to the Institute of Research for Development (IRD) in which further study such as observations of the seed coat, anatomical observations of the leaves and biochemical analysis was undertaken. It was not until 2008, after morphological and genetic studies of this species, that it was recognised as a new species of Coffea. [2] Genotyping analysis reveals C. charrieriana to have diverged from a common ancestor 11.15 million years ago. [3]

Description

Coffea charrieriana can grow up to a range of 5–10 m (16–33 ft) in height and spread 5–7 m (16–23 ft). The shrubs can grow to 1–1.5 m (3 ft 3 in – 4 ft 11 in) high, [7] whilst the branchlets are 1–2 mm (0.039–0.079 in) in diameter. [2] The stipules have tiny hairs at the top and overlap each other and are deltate to triangular in shape and 2 mm (0.079 in) long. C. charrieriana has small and thin leaves that are elliptical in frame. The base of the leaf is slightly wedged in shape whilst the apex of the leaf tapers to a round tip. This tapering point is roughly 7–13 mm (0.28–0.51 in) long. Both the top and bottom of the leaf surface are free of hair and smooth. The leaves' petioles are 2 mm (0.079 in) long. Its leaf blades are 4–8 cm (1.6–3.1 in) in length by 2.2–3.5 cm (0.87–1.38 in) in breadth and features three to seven secondary nerve cells per side of the midvein. The tertiary veins are reticulated, having a thread-like structure. The leaf also has domatia structures which are hairless. Anatomically, the leaf structure consists of an upper epidermis (20–30 μm), palisade mesophyll (20–30 μm), spongy mesophyll (45–70 μm), and lower epidermis (10–20 μm). This structure is quite similar to those found in other Coffea species. [2] However, comparatively to other Coffea species, the leaves are thin at 100–130μm thick and contain very few secondary nerves. These properties differ from other Coffea species specifically found in Central Africa, and resemble that of Phaeanthus ebracteolatus , a wild species found in Africa. The size of the individual leaf structure components are also much smaller than the average seen in most other Coffea species. In addition, this abnormally small leaf characteristic is one of three known in Central Africa, along with C. anthonyi and C. kapakata.

There are one to two inflorescence per stem; each inflorescence contains one flower and two calyculi. The calyculi is divided into upper and lower structures. The lower calyculus has a rim shape with two smaller leave lobes. The upper calyculus has two broadly triangular shaped stipulars and two narrowly shaped elliptical foliar lobes. This plant consists of fruits that are drupes in nature, each containing two pyrenes, with one seed per pyrene. The fruit is connected to a hairless peduncle that is 2 mm (0.079 in) long. The red and fleshy fruit is 9 mm–10 mm × 7 mm (0.35 in–0.39 in × 0.28 in) in size, whilst the coffee seed inside is elliptic in shape and covered in a parenchymatous seed coat. Comparatively to other Coffea species, C. charrieriana lacks sclereids in its seed coat; the absence of sclereids is seen in plants of the genus Psilanthus and other Madagascan species. The seed measures 5 mm (0.20 in) long x 4 mm (0.16 in) wide x 3 mm (0.12 in) thick. Characteristically of Coffea species, the seed is rounded, smooth and grooved. [2] The flowers have no stalk and consist of five petals. The white corolla tube is 1 mm (0.039 in) long while the lobes are 5–8 mm (0.20–0.31 in) long and 2–3 mm (0.079–0.118 in) broad. The flower's gynoecium is a small disc that sits on the top of the ovary and is surrounded by a truncated, smooth calyx limb. The characteristics of the flower closely match those of the Coffea genus. In the flower, the anthers and style protrude out; the anthers are also attached to the corolla. The short filament that connects to the zone between the tube, lobes and corolla is not semi-transparent, making it a distinct species from the closely related genus Psilanthus, in which this section is generally semi-transparent in colour. [2] C. charrieriana also possesses a corolla tube (1mm long), style (10mm long), two lobed stigma (2mm long), anther (3mm long) and anther filament (2mm long). The size of the corolla tube, corolla lobes and anthers differ from other known Coffea species from Central Africa.

Biochemistry

Biochemical analysis of the seeds reveals that they are caffeine-free, [2] this caffeine-free biochemical characteristic is generally found in Madagascan Coffea species. [8] Studies reported 30 out of 47 Madagascan Coffea species had very little or no traces of caffeine. [9] It is the second caffeine-free species, along with C. pseudozanguebariae which grows in a coastal dry forest near the Indian Ocean. [8] It is suggested that the absence of caffeine in the Coffea species is due to spliceosome deficiency. Though the plants contain the necessary genes to produce caffeine, due to a malfunction in the protein synthesis pathway as a result of incorrect splicing patterns, caffeine is not produced. Caffeine absence is caused by a monogenic inheritance pattern, with the involvement of one gene and two alleles; the plant containing the recessive allele leads to no caffeine content. On the other hand, it is likely that caffeine production level is controlled by polygenic inheritance and the amount of caffeine produced is a genetic factor. [9] Through further analysis, it was found that instead of accumulation of caffeine, the deficient caffeine synthase gene responsible for caffeine production had instead produced a substance called theobromine in its place. This discovery by scientists led to further understanding about the genetics of caffeine in Coffea plants, and the ability to hybridize coffee plants with caffeine-free plants to produce a decaf line of seeds with lower caffeine concentrations. It also opened up the option of removing this particular gene in plants containing caffeine to create a caffeine-free plant. [10]

Compared to other Coffea, C. charrieriana along with C. canephora and C. mannii has a significantly lower linoleic acid percentage. C. charrieriana also had the lowest polyunsaturated fatty acid content (<30%) [8] and 0.8% dry matter basis. [2] As a result, though originating from Africa, C. charrieriana is closer phylogenetically to Madagascan than African species (Dussert et al. 2008, 2953). By examining C. charrieriana's leaf components, it forms a separate gene cluster to C. anthonyi, C. arabica, C. canephora, C. humilis, C. kapakata, C liberica, C. liberica var liberica and C. mannii. [11] C. charrieriana also has lower caffeoylquinic acids (CQA) than other Coffea species. [12] From analysing the fatty acid content alone, C. charrieriana is most closely related to C. congensis and forms a separate clade from the other 59 Coffea genotypes. [8]

Further genetic analysis of long tandem repeat retrotransposons (LTR-RT), more specifically of the lineages SIRE and Del, were analysed in C. charrieriana. LTR-RT are redundant sections of the plant genome. It was found that whilst other West and Central African Coffea species contained 4.5–5.1% of SIRE lineage, C. charrieriana contained 3.2%. In addition, C. charrieriana also had the lowest percentage of Del fraction, at 13.1% compared to 14–16.2% found in other West and Central African species. This suggests that with the observations of SIRE and Del, C. charrieriana is genetically distinct to its geographical counterpart species. [13]

Coffea charrieriana also has the largest chloroplast genome within the Coffea genus. When clustering the 52 species from Coffea and Psilanthus, C. charrieriana, along with another species, P. travancorensis, were excluded from the clusters due to poor analysis results. Though C. charrieriana originates from Cameroon, genetic results suggest a placement of C. charrieriana between the two genera of Psilanthus and Coffea. It is genetically similar to West and Central African Coffea species but shares morphological similarities with Psilanthus, such as its vegetation. The difficulty in grouping C. charrieriana is likely the result of ancient hybridisation between C. charrieriana and a Psilanthus chloroplast, leading to a mixed genome. [14]

Alkaloids are found in many plants including coffee and tea, but only very small amounts are present in C. charrieriana. [10]

Cultivation and use

Coffea charrieriana grows in wet places with plenty of sunshine. During dry periods, the species undergoes floral bud morphogenesis, but the flowering buds do not emerge until the next rainfall event. After rain, a flowering event is seen in seven days. The time it takes for flowering of all Coffea species ranges from 5–13 days, making correct timing of hybridization difficult. [15]

Similar to other Coffea species, the fleshy fruit of C. charrieriana contains edible beans. These can be prepared by drying, roasting or grinding, generally to make coffee. As a naturally occurring caffeine-free coffee, it provides an alternative over artificially decaffeinated coffee. [16] With increasing demand for decaffeinated coffee, methods such as plant hybridization between coffee-free species, biotechnology interference of genetics and chemical extraction have been used to artificially decrease caffeine content. [17] Generally, the presence of caffeine acts on the tastebuds, giving caffeinated products a distinct flavour, [18] so as a caffeine-free species, C. charrieriana may not be preferable to coffee drinkers who prefer the taste provided by caffeine. C. charrieriana can be used in plant hybridization as the theobromine can be transferable between breeds, allowing caffeine concentration to be altered when crossed with a species containing caffeine. [10] Seeds from C. charrieriana are currently being developed to become the first naturally caffeine-free coffee available on the market, this bean being coined Decaffito by Brazilian developers. [10]

Another possible use of C. charrieriana is extracting 5-caffeoylquinic acids (CQA) from the coffee leaves, as most Coffea species, including C. charrieriana, contain natural antioxidant compounds. This natural antioxidant can be used in food and nutraceuticals. [19]

Coffea Diversa Farm in Costa Rica is currently[ as of? ] cultivating C. charrieriana. [20] [ dubious ]

Related Research Articles

<i>Coffea</i> Genus of flowering plants

Coffea is a genus of flowering plants in the family Rubiaceae. Coffea species are shrubs or small trees native to tropical and southern Africa and tropical Asia. The seeds of some species, called coffee beans, are used to flavor various beverages and products. The fruits, like the seeds, contain a large amount of caffeine, and have a distinct sweet taste.

<span class="mw-page-title-main">Rubiaceae</span> Family of flowering plants including coffee, madder and bedstraw

Rubiaceae is a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules and sympetalous actinomorphic flowers. The family contains about 13,500 species in about 620 genera, which makes it the fourth-largest angiosperm family. Rubiaceae has a cosmopolitan distribution; however, the largest species diversity is concentrated in the tropics and subtropics. Economically important genera include Coffea, the source of coffee, Cinchona, the source of the antimalarial alkaloid quinine, ornamental cultivars, and historically some dye plants.

<i>Ilex cassine</i> Species of holly

Ilex cassine is a holly native to the southeastern coast of North America, in the United States from Virginia to southeast Texas, in Mexico in Veracruz, and in the Caribbean on the Bahamas, Cuba, and Puerto Rico. It is commonly known as dahoon holly or cassena, the latter derived from the Timucua name for I. vomitoria.

<span class="mw-page-title-main">Coffee</span> Brewed beverage made from coffee beans

Coffee is a beverage brewed from roasted coffee beans. Darkly colored, bitter, and slightly acidic, coffee has a stimulating effect on humans, primarily due to its caffeine content. It has the highest sales in the world market for hot drinks.

<span class="mw-page-title-main">Theaceae</span> Family of flowering plants

Theaceae, the tea family, is a family of flowering plants comprising shrubs and trees, including the economically important tea plant, and the ornamental camellias. It can be described as having from seven to 40 genera, depending on the source and the method of circumscription used. The family Ternstroemiaceae has been included within Theaceae; however, the APG III system of 2009 places it instead in Pentaphylacaceae. Most but not all species are native to China and East Asia.

<i>Coffea arabica</i> Species of coffee plant

Coffea arabica, also known as the Arabica coffee, is a species of flowering plant in the coffee and madder family Rubiaceae. It is believed to be the first species of coffee to have been cultivated and is the dominant cultivar, representing about 60% of global production. Coffee produced from the less acidic, more bitter, and more highly caffeinated robusta bean makes up most of the remaining coffee production. The natural populations of Coffea arabica are restricted to the forests of South Ethiopia and Yemen.

<span class="mw-page-title-main">Coffee bean</span> Seed of the coffee plant

A coffee bean is a seed from the Coffea plant and the source for coffee. It is the pip inside the red or purple fruit. This fruit is often referred to as a coffee cherry, and like the cherry, it is a fruit with a pip. Even though the coffee beans are not technically beans, they are referred to as such because of their resemblance to true beans. The fruits most commonly contain two stones with their flat sides together. A small percentage of cherries contain a single seed, instead of the usual two, called a "peaberry". The peaberry occurs only between 10% and 15% of the time, and it is a fairly common belief that they have more flavour than normal coffee beans. Like Brazil nuts and white rice, coffee beans consist mostly of endosperm.

<i>Pachypodium baronii</i> Species of flowering plant

Pachypodium baronii, the Madagascar palm or bontaka, is a flowering plant in the family Apocynaceae. It has the habit of a robust shrub with a spherical or bottle-shaped trunk. It has several cylindrical branches at the top.

<i>Coffea canephora</i> Species of coffee plant

Coffea canephora is a species of coffee plant that has its origins in central and western sub-Saharan Africa. It is a species of flowering plant in the family Rubiaceae. Though widely known as Coffea robusta, the plant is scientifically identified as Coffea canephora, which has two main varieties, robusta and nganda.

<i>Lycium chinense</i> Species of flowering plant

Lycium chinense is one of two species of boxthorn shrub in the family Solanaceae. Along with Lycium barbarum, it produces the goji berry ("wolfberry"). Two varieties are recognized, L. chinense var. chinense and L. chinense var. potaninii. It is also known as Chinese boxthorn, Chinese matrimony-vine, Chinese teaplant, Chinese wolfberry, wolfberry, and Chinese desert-thorn.

<i>Colletotrichum kahawae</i> Species of fungus

Colletotrichum kahawae is a fungal plant pathogen that causes coffee berry disease (CBD) on Coffea arabica crops. The pathogen is an ascomycete that reproduces asexually. The asexual spores (conidia) are stored within acervuli. This disease is considered to be one of the major factors hampering C.arabica production in the African continent, which represents the current geographic range of the fungus. Coffee berry disease causes dark necrosis in spots and causes the green berries of the coffee to drop prematurely. High humidity, relatively warm temperatures, and high altitude are ideal for disease formation. Given the severity of the disease and the lack of effective control measures, there is great concern that the fungus may spread to other coffee producing continents, such as South America, which could have catastrophic consequences.

<i>Hypothenemus hampei</i> Species of beetle

Hypothenemus hampei, the coffee berry borer, is a small beetle native to Africa. It is the most harmful insect pest of coffee worldwide. Spanish common names of the insect include barrenador del café, gorgojo del café, and broca del café.

<i>Coffea liberica</i> Species of coffee plant

Coffea liberica, commonly known as the Liberian coffee, is a species of flowering plant in the family Rubiaceae from which coffee is produced. It is native to western and central Africa, and has become naturalised in areas including Colombia, Venezuela, the Philippines, Borneo and Java.

Caffeine synthase is a methyltransferase enzyme involved in the caffeine biosynthesis pathway. It is expressed in tea species, coffee species, and cocoa species. The enzyme catalyses the following reactions:

C. robusta may refer to:

<i>Ceroplesis adusta</i> Species of beetle

Ceroplesis adusta is a species of beetle in the family Cerambycidae. It was described by Harold in 1879. It has a broad distribution, and is known from Angola, Benin, Chad, Cameroon, the Democratic Republic of the Congo, the Republic of the Congo, the Central African Republic, Equatorial Guinea, Ghana, Togo, Gabon, Nigeria, Uganda, and the Ivory Coast. It feeds off of plants such as Theobroma cacao, Coffea arabica, Coffea canephora, Albizia adianthifolia, and Celtis zenkeri.

<i>Coffea stenophylla</i> Species of plant

Coffea stenophylla, also known as highland coffee or Sierra Leone coffee, is a species of Coffea originating from West Africa.

<i>Felicia brevifolia</i> A shrublet in the daisy family from South Africa and Namibia

Felicia brevifolia is an evergreen, richly branched shrub of up to 112 m (5 ft) high, that is assigned to the family Asteraceae. It has elliptic to wedge-shaped leaves, of between 12 and 112 cm long, green to gray-green, many with several teeth. The flower heads have about fifteen blue-violet ray florets, encircling many yellow disc florets. This species grows in southern Namibia and the west of South Africa.

<i>Coffea racemosa</i> Species of coffee plant

Coffea racemosa, also known as racemosa coffee and Inhambane coffee, is a species of flowering plant in the family Rubiaceae. It has naturally low levels of caffeine, less than half of that found in Coffea arabica, and a quarter of that in Robusta coffee.

References

  1. Chadburn, H.; Davis, A.P.; Cheek, M.; Onana, J.-M. (2017). "Coffea charrieriana". IUCN Red List of Threatened Species . 2017: e.T18536873A18539476. doi: 10.2305/IUCN.UK.2017-3.RLTS.T18536873A18539476.en . Retrieved 19 November 2021.
  2. 1 2 3 4 5 6 7 8 9 10 11 12 Stoffelen, Piet; Noirot, Michel; Couturon, Emmanuel; Anthony, François (September 2008). "A new caffeine-free coffee from Cameroon". Botanical Journal of the Linnean Society. 158 (1): 67–72. doi: 10.1111/j.1095-8339.2008.00845.x . ISSN   0024-4074 . Retrieved 2021-04-21.
  3. 1 2 Hamon, Perla, Corrinne E. Grover, Aaron P. Davis, Jean-Jacques Rakotomalala, Nathalie E. Raharimalala, Victor A. Albert, and Hosahalli L. Sreenath et al. 2017. "Genotyping-By-Sequencing Provides The First Well-Resolved Phylogeny For Coffee (Coffea) And Insights Into The Evolution Of Caffeine Content In Its Species". Molecular Phylogenetics And Evolution 109: 351-361. doi:10.1016/j.ympev.2017.02.009.
  4. "The Top 10 New Species, 2008". Archived from the original on 2009-05-28.
  5. Chadburn, H., Davis, A.P., Cheek, M. & Onana, J.-M. 2017. (2017). "Coffea charrieriana". IUCN Red List of Threatened Species . 2017: e.T18536873A18539476. doi: 10.2305/IUCN.UK.2017-3.RLTS.T18536873A18539476.en .{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  6. Anthony F, Dussert S, Dulloo E. 2007. The coffee genetic resources. In: Engelmann F, Dulloo E, Astorga C, Dussert S, Anthony F, eds. "Complementary strategies for ex situ conservation of Coffea arabica genetic resources. A case study in CATIE, Costa Rica" 'Rome: Bioversity International, Topical Reviews in Agricultural Biodiversity', 12–22.
  7. "Coffee Tree (Coffea Charrieriana) - Plants | Candide Gardening". 2020. Candide.
  8. 1 2 3 4 Dussert, Stéphane, Andréina Laffargue, Alexandre de Kochko, and Thierry Joët. 2008. "Effectiveness Of The Fatty Acid And Sterol Composition Of Seeds For The Chemotaxonomy Of Coffea Subgenus Coffea". Phytochemistry 69 (17): 2950-2960. [ permanent dead link ]
  9. 1 2 Hamon, P., Rakotomalala, J., Akaffou, S., Razafinarivo, N., Couturon, E., Guyot, R., Crouzillat, D., Hamon, S. and de Kochko, A., 2015. Caffeine-free Species in the Genus Coffea. Coffee in Health and Disease Prevention, pp.39-44.
  10. 1 2 3 4 Preedy, VR (ed.) 2014, Coffee in Health and Disease Prevention, Elsevier Science & Technology, San Diego. Available from: ProQuest Ebook Central. [19 November 2020].
  11. Mees, Corenthin, Florence Souard, Cedric Delporte, Eric Deconinck, Piet Stoffelen, Caroline Stévigny, Jean-Michel Kauffmann, and Kris De Braekeleer. 2018. "Identification Of Coffee Leaves Using FT-NIR Spectroscopy And SIMCA". Talanta 177: 4-11. [ permanent dead link ]
  12. Rodríguez-Gómez, Rocío, Jérôme Vanheuverzwjin, Florence Souard, Cédric Delporte, Caroline Stevigny, Piet Stoffelen, Kris De Braekeleer, and Jean-Michel Kauffmann. 2018. "Determination Of Three Main Chlorogenic Acids In Water Extracts Of Coffee Leaves By Liquid Chromatography Coupled To An Electrochemical Detector". Antioxidants 7 (10): 143. doi:10.3390/antiox7100143.
  13. Guyot, Romain, Thibaud Darré, Mathilde Dupeyron, Alexandre de Kochko, Serge Hamon, Emmanuel Couturon, and Dominique Crouzillat et al. 2016. "Partial Sequencing Reveals The Transposable Element Composition Of Coffea Genomes And Provides Evidence For Distinct Evolutionary Stories". Molecular Genetics And Genomics 291 (5): 1979-1990. doi:10.1007/s00438-016-1235-7.
  14. Charr, J., Garavito, A., Guyeux, C., Crouzillat, D., Descombes, P., Fournier, C., Ly, S., Raharimalala, E., Rakotomalala, J., Stoffelen, P., Janssens, S., Hamon, P. and Guyot, R., 2020. Complex evolutionary history of coffees revealed by full plastid genomes and 28,800 nuclear SNP analyses, with particular emphasis on Coffea canephora (Robusta coffee). Molecular Phylogenetics and Evolution, 151, p.106906.
  15. Noirot, M., Charrier, A., Stoffelen, P. et al. 2016. Reproductive isolation, gene flow and speciation in the former Coffea subgenus: a review. Trees 30, 597–608. https://doi.org/10.1007/s00468-015-1335-8
  16. Rafferty, John P. 2012. "Charrier Coffee | Plant". Encyclopedia Britannica. https://www.britannica.com/plant/Charrier-coffee.
  17. Silvarolla, M., Mazzafera, P. & Fazuoli, L. 2004. 'A naturally decaffeinated arabica coffee'. Nature 429, 826 https://doi.org/10.1038/429826a
  18. Poole RL, Tordoff MG. The Taste of Caffeine. J Caffeine Res. 2017;7(2):39-52. doi:10.1089/jcr.2016.0030
  19. Loizzo, Monica Rosa, and Rosa Tundis. 2019. "Plant Antioxidant For Application In Food And Nutraceutical Industries". Antioxidants 8 (10): 453. doi:10.3390/antiox8100453.
  20. Wallengren, Maja. "Costa Rica takes coffee sustainability to a higher level." Tea & Coffee Trade Journal, March 2015, 24+. Gale General OneFile (accessed October 10, 2020). https://link.gale.com/apps/doc/A421625205/ITOF?u=usyd&sid=ITOF&xid=70552e99