Alia Rahmi
A REVIEW ON INSTANT WHITE COFFEE AND INSTANT DECAFFEINATED COFFEE PROCESSING
WHITE COFFEE INSTAN DAN KOPI INSTAN RENDAH KAFEIN: SEBUAH TINJAUAN TENTANG PROSES PENGOLAHANNYA
Alia Rahmi Jurusan Budidaya Pertanian Fakultas Pertanian UNLAM Jl. Jend. A. Yani Km 36 PO Box 1028 Banjarbaru 70714
ABSTRACT
Instant white coffee is commonly associated with its preceding popular counterpart, the instant decaffeinated coffee. Questions of whether the two products are made from different variety of coffee bean, underwent different processing techniques, or shares different caffeine contents, are poorly explained. The purpose of this review is to provide a better understanding on both products. Instant white coffee and instant decaffeinated (black) coffee are made from similar coffee varieties, the Arabica and the Robusta. Both products undergo similar coffee processing from harvesting, de-pulping, mucilaginous coating removal to drying. The difference takes place in the decaffeination process and the roasting process. Consequently, as instant products, both are processed through an instant making process. Instant decaffeinated coffee is processed through a decaffeination process whereas it is not common for instant white coffee. Instant white coffee is processed through a lower roasting temperature and a shorter roasting time, hence possesses a detracted bitter aftertaste, a lightened colour, a higher caffeine content and a high acidic note. Instant decaffeinated (black) coffee is processed at a higher roasting level (160 – 280oC; 20 – 40 minutes), therefore bears bitter aftertaste, dark colour, lower caffeine content and slightly acidic. The claim for health benefits, although not specifically on lean body mass, in white coffee, it is maybe true due to the high caffeine, chlorogenic and cafeic acid content. However, the claim for softness on the stomach is still debatable. Keywords: coffee, white coffee, decaffeinated coffee, instant
ABSTRAK
White coffee instan seringkali dikatagorikan sama dengan kopi instan rendah kafein. Pertanyaan seputar varietas kopi yang digunakan, proses pengolahan, dan kadar kafein kedua produk tersebut masih belum terjawab secara jelas. Tujuan dari tinjauan ini adalah untuk memberikan gambaran lebih jelas tentang kedua produk tersebut. White coffee instan dan kopi instan rendah kafein dibuat dari varietas kopi yang sama, yaitu Arabica dan Robusta. Kedua produk tersebut diolah dengan cara yang sama melalui tahap pemanenan, pelepasan daging buah, penghilangan lapisan luar biji, dan pengeringan. Perbedaan pengolahannya adalah pada tahap dekafeinasi dan penyangraian. Selanjutnya, sebagai produk instan, kedua produk mengalami tahap instanisasi. Kopi rendah kafein melalui tahap dekafeinasi yang tidak umum dilakukan terhadap white coffee. White coffee disangrai pada suhu yang lebih rendah dalam waktu yang lebih singkat, sehingga memiliki rasa yang tidak terlalu pahit, warna yang lebih muda, kadar kafein yang lebih tinggi dan rasa asam yang lebih kuat. Kopi rendah kafein disangrai pada suhu lebih tinggi dalam waktu lebih lama (160 – 280oC; 20 – 40 menit), sehingga memiliki rasa lebih pahit, warna lebih gelap, kadar kafein lebih rendah dan rasa tidak terlalu asam. Klaim manfaat kesehatan white coffee, meski tidak spesifik untuk mengendalikan berat badan, mungkin benar karena kadar kafein, asam klorogenat dan asam kafeatnya yang tinggi. Bagaimanapun, klaimnya bagi penderita sakit maag masih perlu dukungan penjelasan ilmiah. Keywords: Kopi, White coffee, Kopi Instan rendah kafein
INTRODUCTION white coffee for instant white coffee and black coffee for instant decaffeinated black coffee, respectively. The emergence of white coffee commercials on Questions of whether the two products are made Indonesian broadcasting television has caught the from different variety of coffee bean, underwent attention of viewers. The product is perceived by different processing techniques, or shares different potential customers as a new coffee product that is caffeine contents, are poorly explained. The review soft on the stomach, has a healthy diet (lean body attempted to provide a better understanding about mass) promoting effect, and for some, is low in both products. caffeine. The instant version of the product is commonly associated to its preceding popular METHODOLOGY counterpart, the instant decaffeinated (black) coffee. The products discussed will further bear the term This review is narrative and was carried out by
120 Agroscientiae ISSN 0854-2333 A review on instant white coffee…… summarising, interpreting, and critically evaluating solely in decaffeination process is not popular. (meta-synthesis) the existing literature on white The use of decaffeinating agent following a coffee, decaffeinated coffee and instant coffee water process is more practised. There are at making. The lacking of scholarly journals discussing least eight methods known in decaffeination about the reviewed products, urges the use of a process including water extraction, direct selective number of published materials of web- method, indirect method, triglyceride method, based and practice literature that are relevant and CO2 process and Roselius process (Senese best address the topic discussed. 2010; Coffee Research Institute 2006; Barista Guru 2004; Swiss Water Process 2010). All the RESULTS AND DISCUSSION eight methods except Roselius process are practised by coffee manufacturers around the The Arabica (Coffea arabica) and Robusta world. Roselius process is no longer used (Coffea canephora var. robusta) are the most commercially due to safety issue (Uher 2008). common coffee varieties in its worldwide trade Solid/liquid extraction principle is fundamental in (Ranken, Kill & Baker 1997). Coffee is harvested as decaffeination process. coffee cherry. Structure of coffee cherry is shown in Figure 1. Coffee bean is the part which will be A.1. Water extraction processed further in coffee manufacturing. The outer Senese (2010) wrote that in water part of coffee cherry are removed. Removal of the extraction, green coffee beans are soaked outer skin and pulp is done by pulping machines, in hot water (almost boiling temperature). while mucilaginous coating on the beans are Hot water leaches out caffeine and flavour removed by various methods such as fermentation, components from the beans. Passing the the use of commercial pectinase, or washing extract, which is rich in caffeine and treatments (Belitz, Grosch & Schieberle 2009; Potter flavour components, through activated & Hotchkiss 1998). charcoal will yield free caffeine extract. The latter extract is still rich in flavour components. To restore the flavour, the extract is then used to soak original green coffee beans. The driving force to equilibrium causes the flavour to penetrate back into the green coffee beans. Flavour restored green coffee beans which are free of caffeine are ready to be dried.
A.2. Swiss Water process Swiss Water process is named after Figure 1. Structure of coffee cherry (Coffee Swiss Water Decaffeinated Coffee processing 2011) Company. The process is using water to extract caffeine, however before Coffee beans are then dried under the sun or by extraction, water is already saturated with the use of drying unit. Dried coffee beans are still green coffee bean flavour by soaking the green (not yet roasted). Green coffee beans are green coffee beans in the water. This shipped to coffee manufacturers worldwide. Then, saturated water is called “flavour charged the coffee beans undergo further process, including water”. The saturation level of flavour decaffeination and roasting process. Instant coffee charged water is in equilibrium with the making is done at a later stage, after the beans are flavour components in the green coffee roasted. Sections will be dedicated individually for beans. Due to the equilibrium state, when decaffeination process that is more common for fresh batch of green coffee beans are black coffee, roasting process indicative to white soaked, only caffeine will leach out, while coffee and instant coffee making for both black flavour components are kept. Swiss Water coffee and white coffee. Process (2010) claimed that this process takes about 8-10 hours to extract 99.9% A. Decaffeination Process (Indicative to Black caffeine. Caffeine free coffee beans are Coffee) now ready to be dried and further Decaffeination process is aimed at removing processed or shipped to coffee caffeine from coffee beans, without spoiling its manufacturers around the world. Caffeine distinct flavour. Coffee is decaffeinated if it is which is still present in flavour charged 99.9% caffeine free (Swiss Water Process: water, will be trapped using activated decaffeination 101 2008). carbon filter, and the flavour charged Caffeine and flavour components in coffee water can be used again to extract beans are water soluble, thus, the use of water caffeine from a new batch of green coffee beans. This process is shown on Figure 2.
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beans are soaked twice in two different liquid. The first soaking is done in hot water to let caffeine mobilise to the beans surface. The second soaking is done in coffee oil for several hours at high temperature (Barista Guru 2004). Coffee oil can be obtained by pressing spent coffee grounds. The second soaking is to let caffeine extracted by coffee oil. No flavour component is extracted in this method. The coffee beans can be taken out from coffee oil and dried.
Figure 2. Swiss Water Process (Brainy Bean 2011) A.6. CO2 process Potter and Hotchkiss (1998) suggested A.3. Direct method that CO2 process is an advanced Decaffeination process using this decaffeination process to overcome the method is done by contacting green coffee problem with solvent removal and solvent beans and solvent directly. Solvent is vapour recovery. This process is used to extract caffeine. Methylene conducted at high pressure above the chloride and ethyl acetate are the two critical point which then called as solvents mostly used for decaffeination supercritical CO2 extraction. At this process (Brennan et al. 1990 and Clarke operating condition, CO2 acts as liquid 1990, cited in Fellows 2009). Before solvent with penetrating ability as gas to extraction, green coffee beans are extract caffeine. Around 97-99% caffeine steamed for 30 minutes. Then, the can be extracted by this process (Senese softened beans are rinsed with solvent 2010). Before being contacted with CO2 repeatedly for about 10 hours (Barista the green coffee beans are steamed to Guru 2004). Caffeine is extracted during mobilise caffeine to the surface of the the rinsing step. Coffee beans have to be beans. steamed again to evaporate the remaining The remaining CO2 in the beans can solvent. Drying coffee beans will also easily be removed as it dissipates when evaporate the remaining solvent, leaving the beans are returned to room no solvent residue in the coffee beans. temperature and pressure. While Caffeine Coffee beans are now free of caffeine and in CO2 can be removed with the use of free of solvent, ready for drying. charcoal or sparkling water (Senese 2010; Coffee Research Institute 2006). A.4. Indirect method Indirect method also uses methylene A.7. Roselius process chloride and ethyl acetate, however, green Roselius process is named after its coffee beans and its solvent are not inventor Ludwig Roselius, a German contacted directly. This method is similar coffee wholesaler. The process is similar to water extraction (Barista Guru 2004), to direct method, but the solvent used is where caffeine and flavour components benzene (Uher 2008). As benzene has are extracted into water. The difference to health relating concerns, this process is water extraction is the use of solvent to no longer used. remove caffeine from the extract. In water extraction activated charcoal is used to B. Roasting Process (Indicative to White Coffee) trap caffeine and release flavour The term white coffee is known in English component to the filtrate. Indirect method speaking countries as coffee with whitener, i.e. mixes solvent and water extract to remove milk or cream. In the United States, a different caffeine by heating. As this solvent-extract roasting technique is subjected to dried coffee mix is heated, caffeine and solvent beans to produce white coffee. A lighter roast vaporizes, leaving the mix with high level is applied, hence producing a lighter colour flavour components. The use of this latter and a less bitter aftertaste (Owen 2001). extract to soak fresh coffee beans batch Middle Eastern countries are also familiar with will be similar to water process done by white coffee. The Lebanese have “ahweh bayda” the Swiss Water® Decaffeinated Coffee white coffee, a caffeine-free drink made from Company. water, orange blossom water, and sugar (taste of Beirut 2010). Moreover, a native Yemen white A.5. Triglyceride method coffee, made simply from ground shell of coffee In triglyceride method, green coffee bean without roasting. It is brewed with spices
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and served in the same manner as regular black causes not only a lower degree of sugar coffee (Cassistre 2012). caramelisation and bitter tastants generation, but In Southeast Asia, Malaysia has been known also a lower degree of caffeine and acid to be the inventor of white coffee. Originated from breakdown. The shorter roasting time results the town of Ipoh, white coffee is made from similar impacts as resulted by the temperature. coffee beans lightly roasted in margarine, brewed Caffeine content in caffeinated coffee ranges in the same manner as regular black coffee, and from 58 to 259 mg per dose, and decaffeinated served with sweetened condensed milk or non- coffee has as much as 17.7 mg per dose (Preedy dairy creamer and sugar (Zubil 2011). 2012; CSPI 2012). Caffeine sublimes at ca. There is one specific process that 180oC (O’Neil 2006; Preedy 2012; Spiller 1998). differentiates white coffee from the black one: the The roasting temperature of regular black coffee roasting process. The ingredients and level of is ca. 40oC above its sublimation point (Ranken white coffee roasting process is different from et al. 1997). Since white coffee is processed at a black coffee. Despite the differences, similar lower temperature, less caffeine sublimes. In coffee varieties are used in white coffee, namely other word, at the same dry weight, white coffee the Arabica and the Robusta. may contain higher caffeine content than that of Regular black coffee is roasted with regular black coffee. margarine and sugar. White coffee is roasted Regular black coffee is slightly acidic (Flament without sugar. The absence of sugar produces 2002), while high acidic note is perceived in white different roasted coffee flavour profile. Sugar coffee. The high acidic note in white coffee is due caramelisation is a temperature dependent to its lighter roasting process which leaves a reaction (Heldman & Lund 2007). The reaction considerable amount of chlorogenic and cafeic may start as low as 75 – 95oC (Diaz & Clotet acids (Eggers 2005; Flament 2002; Clarke & 1995 in Simpson 2012) and as the temperature Macrae 1988). The claim over the softness of increases, so is its reaction rates (Park et al. white coffee on the stomach then come into 1998 in Simpson 2012). Vaclavik and Christian questions, because the high acidic note may be (2008) reported that most sugar caramelise when caused by high acid content or low pH. Both the heated to 170oC. At regular roasting temperature acid content and pH are certainly (188 - 280oC) of black coffee, high degree of disadvantageous for ulcer patients. However, the caramelisation occurs, resulting in bitter acids combined with caffeine are claimed to have aftertaste and dark colour which are observed in a positive effects on glucose level, cardiovascular regular black coffee (Ranken et al. 1997; Clarke and dieting fitness (Cornelis & El-Sohemy 2007). & Macrae 1988). The absence of sugar in white coffee roasting detracts the bitter aftertaste and C. Instant Coffee Making lightens the colour. Instant coffee making utilizes extraction Moreover, white coffee processing employs a principle in one of its process. There are three lighter roasting level, in terms of temperature and steps in instant coffee making, including duration. During the writing of the review, no extraction, dehydration, and aromatization. The scientific publication is found concerning the underlying principle in making an instant coffee is exact roasting temperature and time of white to extract the coffee flavour from roasted coffee coffee. Regular black coffee is roasted at 160 – beans, dehydrating the extract which contains 280oC for 20 – 40 minutes (Belitz et al. 2009; coffee flavour components, and not the coffee Eggers 2005; Ranken et al. 1997). At this grounds, will result in readily solubilised coffee temperature, intense bitter tastants of black (instant). Unlike decaffeination process which coffee are produced (Frank, Zehentbauer & uses green coffee beans, extraction process in Hofmann 2006). Lower roasting temperature instant coffee making uses roasted coffee beans.
Figure 3. Six percolator countercurrent extraction battery (Potter & Hotchkiss 1998)
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Table 1. Review on instant white coffee and decaffeinated coffee processing Coffee Varieties and Instant White Coffee Instant Decaffeinated (Black) Coffee Processing Steps Coffee Varieties Arabica (Coffea arabica) and Robusta (Coffea canephora var. robusta) Harvesting Subjected to similar process selection De-pulping Subjected to similar process selection Mucilaginous Coating Subjected to similar process selection Removal Drying Subjected to similar process selection Decaffeination Process Not common - Subjected - Resulted in a lower (or no) caffeine content Roasting Process - Subjected - Subjected - No sugar added - Sugar added - Lower roasting temperature - Normal roasting temperature (160 - - Shorter roasting time 280oC) - Resulting in a detracted bitter - Normal roasting time (20 – 40 aftertaste, a lightened colour, a minutes) higher caffeine content and a - Resulting in a bitter aftertaste, a high acidic note dark colour, a lower caffeine content and slightly acidic Instant Making Process Subjected to similar process selection
Potter and Hotchkiss (1998) describes that lower caffeine content and slightly acidic. The extraction step in instant coffee making is review is summarised on table 1. conducted in an extraction battery which consists Instant white coffee and instant decaffeinated of six to eight connected percolators. Extraction (black) coffee can be obtained by employing the battery of an instant coffee making is shown in above methods. In detail, the process is started Figure 3. Each percolator operates at different with pulping the coffee cherry, followed by temperatures. This condition is set to achieve decaffeination process (for decaffeinated coffee), optimum extraction, avoiding heat damage and drying the green coffee beans, roasting (lower extracting too much of bitter elements. The level for white coffee) and grinding the coffee different temperatures at each percolator is beans, brewing coffee ground (extracting), arranged in decreasing order from about 150 – dehydrating the extract, aromatisation process, 70 oC, to maximise the extraction of the desired and finally instant white coffee or instant flavour components, to remove most of the decaffeinated (black) coffee is ready for readily soluble solids and to hydrolyse less packaging and sale. soluble coffee bean carbohydrates. This process yield about 40% of the weight of roasted ground CONCLUSION coffee bean. The extract is then rapidly cooled 1. Instant white coffee and instant decaffeinated and dehydrated. (black) coffee are made from similar coffee Instant white coffee and instant decaffeinated varieties, the Arabica and the Robusta. Both (black) coffee are made from similar coffee products undergo similar coffee processing from variety, the Arabica and Robusta. Both products harvesting, depulping, mucilaginous coating undergo similar coffee processing from removal and drying. The difference takes place in harvesting, depulping, mucilaginous coating the decaffeination process and the roasting removal and drying. The difference takes place in process. Consequently, as instant products, both the decaffeination process and the roasting are processed through an instant making process. Consequently, as instant products, both process. are processed through an instant making 2. Instant decaffeinated coffee is processed through process. a decaffeination process whereas it is not Instant decaffeinated coffee is processed common for instant white coffee. Instant white through a decaffeination process whereas it is coffee is processed through a lower roasting not common for instant white coffee. Instant white temperature and a shorter roasting time, hence coffee is processed through a lower roasting possesses a detracted bitter aftertaste, a temperature and a shorter roasting time, hence lightened colour, a higher caffeine content and a possesses a detracted bitter aftertaste, a high acidic note. Instant decaffeinated (black) lightened colour, a higher caffeine content and a coffee is processed at a higher roasting level, high acidic note. Instant decaffeinated (black) therefore bears bitter aftertaste, dark colour, coffee is processed at a higher roasting level, lower caffeine content and slightly acidic. The therefore bears bitter aftertaste, dark colour, claim for health benefits, although not specifically
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on lean body mass, in white coffee, it is maybe Heldman, D & Lund, DB 2007, Handbook of Food true for the high caffeine, chlorogenic and cafeic Engineering, 2nd Edition, CRC Press, Florida. acid content. However, the claim for softness on O’Neil, M J 2006, The Merck Index – An the stomach is still debatable. Encyclopedia of Chemicals, Drugs, and Biologicals. 14th Edition. Merck and Co., Inc., REFERENCES New Jersey. Barista Guru 2004, Key facts about decaffeination, Owen, D 2001, What is “White coffee?”, accessed Barista Guru – Decaf Coffee Facts, accessed 21 May 2014, < http://coffeefaq.com/ 27 March 2011, site/node/53>
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