chapter 150

THE MOST RECENT STUDIES IN SCIENCE AND ART

CHAPTER 150

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NEW TRENDS IN TURKISH COFFEE

Ayse Nur YUKSEL, Mustafa BAYRAM Coffee is the most, popular and widely consumed beverage in the world. After crude oil, it ranks second in all commodities (Küçükkömürler and Özgen, 2009). Most of the tropical and subtropical countries produce coffee and it is the main agricultural product to export. Coffea arabica (Arabica) and Coffea robusta (Robusta) are the most common and known coffee species which are used in production of coffee beverages (Esquivel and Jimenez, 2012). Coffea arabica is the most preferred due to its sensory properties (Bertrand et al., 2003). Robusta is generally used in coffee blends. Recently, epidemiological and clinical studies have been attributing beneficial health effects to this drink, mainly because of its high content of phenolic compounds, which make coffee one of the highest contributors to antioxidant intake in western diets (Farah, 2009). Due to its caffeine content, coffee can have a stimulating effect in humans (Esquivel and Jimenez, 2012, Chandrasekar and Viswanathan, 1999) such as; keeping people awake and increasing mental alertness. In addition, the researchers found that caffeine intake reduces the risk of type 2-diabetes and obesity (Zheng, 2014). Coffee beans are found in a coffee fruit (also called cherry), which consists of skin or pericarp (green in unripe and red-violet or deep red in ripe fruits), pulp, mucilage, parchment and silver skin covers both coffee beans (Berbert et al, 2001). The layers in coffee fruit are given in Figure 1.

Figure 1. Layers in a coffee fruit (Esquivel and Jimenez, 2012)

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Coffee Processing Firstly, coffee fruits are harvested in one of three ways: picking, stripping or mechanical harvest. Only ripe cherries are picked one by one by hand; therefore it is expensive method due to the need of labor. It is used to harvest the finer Arabica beans. Immature, ripe and overripe seeds are also collected by stripping of twigs. Mechanical harvest is made by shaking trees or striping with an apparatus (Farah, 2012). After harvesting, pulp extraction is made to the coffee fruits. There are two pulp extraction methods as wet and dry (Esquivel and Jimenez, 2012). With dry processing, freshly picked cherries are dried to prevent the fruit from spoilage, before hulling. The moisture content is decreased approximately to 10-12 %. After drying, dried husk is removed, leaving a mucilaginous material (silver skin) on the seed surface. Then, coffee seeds are mechanically and electronically sorted to get high quality seeds. Wet processing is used for handpicked, fully ripe fruits. With wet processing, cherry selection is made in floatation tanks, followed by soaking and fermentation. The purpose of the fermentation process is to remove the layer of mucilage by dissolving of the layer by natural occurring enzymes. After the seeds are dried, coffee is sized, graded and sorted. Then green coffee beans are ready to roasting (Farah, 2012). In Figure 2, general coffee production steps are shown.

Figure 2. General coffee production steps


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Coffee roasting is an important operation to develop the specific organoleptic properties (flavor, aroma and color) which underlie the quality of coffee and guarantee a satisfactory beverage (Hernandez et al., 2008). Roasting process gives the coffee beans to its characteristic aroma and taste. Drum roasters are used common in home and industry. Coffee beans are directly in contact with hot surface. As newer method for roasting, fluidized bed roasters are used due to the fastness of process and better control of air temperature and speed. In addition, more homogenous color is obtained in contrast to other roasters (Farah, 2012). Roasting process occur with two phases: drying and roasting. When roasting temperature reaches to 190 °C, chemical reactions such as: oxidation, reduction and hydrolysis occur. These reactions give sensory quality to coffee. In addition, important changes in color, volume, weight, bean pop, pH, volatile components and CO2 formation occur. After this step, the beans must be cooled fast to stop the reactions to prevent an excessive roast which decreases the quality of the coffee (Hernandez et al., 2007, 2008). During roasting, textural properties of coffee beans are also changed. Beans become more brittle and crumbly. However, it is necessary to provide effective grinding which will be carried out before brewing. Uniform grinding affects the extraction rate of coffee (Pittia et al., 2001). For Turkish coffee, coffee beans should stay humid after roasting to help extreme grinding (Yılmaz et al., 2017). There are three types of grinders, mortar/pestle, hand mill and electric grinder (stone, hammer, disc and ball-mills) (Başarır, 2005). Traditionally, in old times, special hand mill “değirmen” was used for the grinding of roasted coffee seeds. However, today electric grinders are mostly used instead of hand mills. Electric grinders have one disadvantage as during process beans are overheated, therefore flavor is lost in the air (Başarır, 2005). But, this heating problem is solved by using different milling techniques. Brewing method is also important process to develop chemical composition. Almost all brewing methods uses hot water, specialists agree that it should not exceed 90-95 °C. French press, filtration, boiled coffee, electric coffee maker, espresso machine and Italian coffee maker are the most common brewing methods (Farah, 2012). Turkish Coffee Preparation The main difference of Turkish coffee from the other coffee types is the traditionally brewing method. Coffee is brewed in coffee pots also called “cezve” (Kramer, 2013) (Figure 3.); therefore it is called Turkish Coffee (Yılmaz et al., 2017). Roasting degree is one of the most important factors to obtain good quality Turkish coffee. After roasting, Turkish coffee should be finely ground. Roasting profile measured with Agtron Coffee Roast Analyzer should be average #60 or higher for roasted coffee beans and #65 for ground Turkish coffee. The size of 7075 % of ground particles should be between 75 and 125 microns (Özgür, 2012). As a note, raw material is very important for Turkish coffee to obtain delicious taste and flavor. Therefore, Arabica is preferred for the best Turkish coffee. For preparation of Turkish coffee, fine ground coffee (approximately 7 g) is put into coffee pot (traditionally named as “cezve”) and a cup of cold water is added. Ad-

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ditionally, sugar may be added, if preferred. The maximum brewing time should be 3 minutes. Turkish coffee is boiled two times to obtain thick foam. Then, it is served in small cups without filtering. In Turkey, four sweetness degrees are used as; “acı” (plain, no sugar), “az şekerli” (less sweet, a half level of teaspoon), orta şekerli (medium, one level of teaspoon) and “çok şekerli” (very sweet, one and half or two level of teaspoons). Sometimes but not general, milk is added to Turkish coffee. The foam stability is also important. In the literature, there are limited studies about foam and foam stability of Turkish coffee (Özkara, 2012, Zheng, 2014).

Figure 3. Equipment for Turkish coffee preparation 1) Coffee pot, 2) A cup of Turkish coffee, 3) (Anon., 2018a) and 4) (Anon., 2018b) Coffee machines, 5) Electrical coffee pot (Anon., 2018c) Preparation equipment Traditionally, Turkish coffee is cooked in coffee pot on heater. With the technology, electrical coffee pots and coffee machines are developed. Preparation method of electrical coffee pots is almost same with regular coffee pots, however, heating method is different: there is a resistant hidden in pot. On the other hand, in coffee machines, after addition of coffee and sugar (if preferred), water is pumped automatically into the coffee pot and machine has sensors to sense boiling depends on coffee foam level. It automatically stops heating and let the consumer know the coffee is ready to serve by light and sound. Quality Parameters of Ground Coffee Chemical properties of ground coffee from the declaration (No: 2016/7) of Turkish Food Codex of Republic of Turkey Ministry of Food, Agriculture and Livestock are given in Table 1 (TGK, 2016). Table 1. Chemical properties of ground coffee Chemical Properties

Values

Moisture, % w/w Ash content, % d.b. w/w Ash content, insoluble in acid, % d.b. w/w Ash content, soluble in water, % total ash content w/w Caffeine, % d.b. w/w Water soluble matter, % d.b. w/w

5.0 3.0-6.0 1.0 65.0 1.0 25.0


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Economic Value of Turkish Coffee Turkey is importing green coffee beans (Coffea arabica, Coffea robusta) from the countries such as; Brazil, Colombia, Guatemala, India, Ethiopia, Uganda and Vietnam. Total quantities of imported coffee (excluding roasted and decaffeinated) (ITC, 2018) can be seen on Figure 4. On the other hand, Turkey is exporting Turkish coffee as roasted and/or ground coffee to the countries such as; Netherlands, Romania, United States of America, Germany, Saudi Arabia, etc. In 2016, total quantity of exported roasted coffee (excluding decaffainated) is 935 tons (ITC, 2018). Total quantities of exported roasted coffee (excluding decaffainated) and countries whose imports roasted coffee (excluding decaffainated) from Turkey based on years are shown on Figure 5 and 6, respectively.

Figure 4. Imported coffee quantities of Turkey based on years

Figure 5. Exported roasted coffee (excluding decaffainated) quantities of Turkey based on years

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2014 2015 2016

Countries

United Arab Emirates Russian Federation Iran, Islamic Republic of Bulgaria Georgia Azerbaijan France Kuwait Libya, State of Iraq United Kingdom Saudi Arabia Germany United States of America Romania Netherlands Free Zones

0

50

100

150

Exported quantity, tons

200

250

Figure 6. Countries whose imports roasted coffee (excluding decaffainated) from Turkey based on years Total coffee consumption worldwide is about 157,382 (thousand in 60 kg bags) in years of 2016-2017. In Europe, it is 51,693 (thousand in 60 kg bags) and Asia & Oceania follow Europe with 34, 425 (thousand in 60 kg bags). It is 29,380 and 25,335 for North America and South America, respectively (ICO, 2018). Conclusion Turkish coffee can be found in every restaurant and coffee houses, because it is a traditional and cultural drink of Turkey. Turkish coffee consumption is increasing throughout the world with development of Turkish coffee machines and coffee chains. Today, due to huge increase in coffee consumption, different types of Turkish coffee (flavored of cardamom, chocolate, mastic tree gum and vanilla, or blends “Ottoman coffee” of carob, sahlep, terebinth, coffee and cream) are available in markets. Moreover, in some Arabic coffees, which are similar to Turkish coffee, hell (cacule) and amber are used. In general, over roasted coffee is used in Arabic coffee. REFERENCES 1. Anon., 2018a, https://www.arcelik.com.tr/turk-kahve-makinesi/k-3190-p-telve-icecekhazirlama.html (Accessed Date: 01.02.2018) 2. Anon., 2018b, https://www.arzum.com.tr/kategori/okka-okka-turk-kahvesi-makinesi /127 (Accessed Date: 01.02.2018) 3. Anon., 2018c, https://www.krc.com.tr/urun/karaca-silverline-elektrikli-cezve (Accessed Date: 01.02.2018) 4. S. Başarır, “Comparative Study on Design of Turkish Coffee Brewing Machines for Selfservice: “Telve”, “Kahve” and “Gondol”, M. Sc. Thesis in İzmir Institute of Technology, Turkey. 2005. 5. P. A. Berbert, D. M. Queiroz, E. F. Sousa, M. B. Molina, E. C. Melo, L. R. D. Faroni, “Dielectric Properties of Parchment Coffee”, Journal of Agricultural Engineering Research, 80:65-80, 2001.


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6. B. Bertrand, B. Guyot, F. Anthony, P. Lashermes, “Impact of the Coffea canephora gene Introgression on Beverage Quality of C. arabica”, Theoretical and Applied Genetics, 107: 387–394, 2003. 7. V. Chandrasekar, R. Viswanathan, “Physical and Thermal Properties of Coffee”, Journal of Agricultural Engineering Research, 73: 227-234, 1999. 8. P. Esquivel, V. M. Jimenez, “Functional Properties of Coffee and Coffee By-products, Food Research International, 46(2): 488-495, 2012 9. A. Farah, “Coffee As a Speciality and Functional Beverage”, Editor: P. Paquin, Functional and Speciality Beverage Technology, Woodhead Publishing Limited, UK, Chapter 15, 370-395, ISBN:978-1-845-69342-8, 2009 10. A. Farah, “Coffee Constituents”, Editor: Y. Chu, Coffee: Emerging Health Effects and Disease Prevention, Wiley-Blackwell, USA, Chapter 2, 21-58, ISBN: 978-0-470-95878-0, 2012. 11. J. A. Hernandez, B. Heyd, C. Irles, B. Valdovinos, G. Trystram, “Analysis of the Heat and Mass Transfer During Coffee Batch Roasting”, Journal of Food Engineering, 78: 11411148, 2007. 12. J. A. Hernandez, B. Heyd, G. Trystram, “Prediction of Brightness and Surface Area Kinetics During Coffee Roasting”, Journal of Food Engineering, 89: 156-163, 2008. 13. ICO, 2018, International Coffee Organization, http://www.ico.org/trade_statistics.asp (Accessed Date: 01.01.2018). 14. ITC, Trade Map, https://www.trademap.org/Index.aspx (Accessed Date: 01.02.2018) 15. A. Kramer, “Brewing Culture”, Editors: R. W. Thurston, J. Morris, S. Steiman, Coffee: A Comprehensive Guide to the Bean, the Beverage and the Industry, Rowman & Littlefield Publishers, 336-339, ISBN: 978-1442214408, 2013. 16. S. Küçükkömürler, L. Özgen, “Coffee and Turkish Coffee Culture”, Pakistan Journal of Nutrition, 8(10): 1693-1700, 2009. 17. N. Özgür, 2012, “Türk Kahvesi Standartları ve Pişirme Ekipmanları Teknik Analizi”, Türk Kahvesi Kültürü ve Araştırmaları Derneği. http://www.turkkahvesidernegi.org/ tkkad/detay/STANDARTLARIMIZ/23/18/0 (Accessed Date: 29.01.2018). 18. K. T. Özkara, “Determination of Processing Properties of Turkish Coffee”, M. Sc. Thesis in University of Gaziantep, Turkey, 2012. 19. P. Pittia, M. Dalla Rosa, C. R. Lerici, “Textural Changes of Coffee Beans as Affected by Roasting Conditions”, Lebensmittel–Wissenschaft & Technologie, 34: 168-175, 2001. 20. TGK, 2016, “Türk Gıda Kodeksi Kahve ve Kahve Ekstraktları Tebliği (2016/7)”, T.C. Gıda, Tarım ve Hayvancılık Bakanlığı, http://www.mevzuat.gov.tr/Metin. Aspx?MevzuatKod=9.5.21446&MevzuatIliski=0&sourceXmlSearch=2016/7 (Accessed Date: 01.02.2018). 21. B. Yılmaz, N. Acar-Tek, S. Sözlü, “Turkish Cultural Heritage: A Cup of Coffee”, Journal of Ethnic Foods, 4: 213-220, 2017. 22. C. Zeng, “Complexation Assisted Foam Fractionation of Caffeine from Its Aqueous Solution”, Ph. D. Dissertation in Technical University of Munich, Germany, 2014.