Quantitative Analysis of Caffeine Content from Coffee Growing in Different Regions of Rwanda
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© IJARW | ISSN (O) - 2582-1008 July 2021 | Vol. 3 Issue. 1 www.ijarw.com QUANTITATIVE ANALYSIS OF CAFFEINE CONTENT FROM COFFEE GROWING IN DIFFERENT REGIONS OF RWANDA. 1 2 3 Barasikina Jean d’Amour , Kagiraneza Olivier Placide , NSHOGOZ Gilbert 1University of Rwanda /College of Science and Technology, Department of Chemistry, POBX: 3900 Kigali-Rwanda 2Eduardo Mondlane University, Department of Chemical Engineering, postal 257 Maputo- Mozambique 3lecturer at University of Rwanda-College of Science and Technology. ABSTRACT Coffea is considered as a large genus (with more than 90 species) of flowering plants belongs in the family Rubiaceae. However, coffee ranks as one of the major commodity crops in the world and is the essential export product of some countries. Moreover, coffee beans found on the market are produced from two different species of the Coffea genus such as Coffea arabica and Coffea canephora syn. Coffea robusta . Nowadays, due to its pleasant taste, aroma, stimulant effect, and health benefits, coffee is one among the most widely consumed beverages throughout the world includes Rwanda country. Both species of coffee present a rich source of biologically active compounds such as caffeine. Caffeine is defined as a xanthine alkaloid compound that acts as a stimulant in humans. It is normally found in the leaves and beans of the coffee plant. In addition to that, caffeine is widely used to enhance alertness and improve performance as it acts as psychostimulant. Consequently, the strong pharmacological effects of caffeine have led to consumer demand for caffeine- free coffee beverages. Due to the high consumption rate of caffeine and its potential physiological effects, both health professionals and consumers need to know the exact caffeine content in food. The way to assess their content to find a more precise relationship between the amounts of consumed caffeine and it’s physiological effects ,it is therefore important to precisely determine the caffeine content in different coffee types. The research’s objective was to determine Caffeine content in coffee growing in different Regions of Rwanda in order to identify the coffee region that contains the highest amount of caffeine. The Coffee samples presenting four growing regions of Rwanda have been taken from NAEB and brought to the College of Science and Technology (CST) chemistry department Laboratory. Quantitative analysis of Caffeine was performed by using a UV-Visible spectrometer (UV-Vis spectrometer) at 650 nm. The results showed that the highest caffeine concentration was obtained from coffee grown in the Western province region presented by GASHONGA Coffee (RUSIZI District) with 9.4±1.962 ppm of caffeine concentration. This was followed by coffee grown in the Southern province region presented by MARABA Coffee (HUYE District) which contains 7.5333±0.8885 ppm of caffeine concentration. The third coffee in caffeine concentration was MUSASA Coffee (GAKENKE District) grown in the Northern Province region which contains 3.8±1.270ppm of caffeine. The last caffeine concentration was obtained in coffee from Eastern province, presented by HUMURE Coffee (GATSIBO District) with 3.2667± 1.578ppm of caffeine Western province region presented by GASHONGA Coffee (RUSIZI district). Keyword: Coffee; Caffeine; alkaloid; stimulant effects; pharmacological effects 1. INTRODUCTION family Rubiaceae. However, coffee ranks as one of the major commodity crops in the world and is the 1.1. Background essential export product of some countries. Coffee Coffea is considered as a large genus (with more beans are widely cultivated in tropical countries than 90 species) of flowering plants belongs in the in plantations for both local consumption and IJARW1495 International Journal of All Research Writings 1 © IJARW | ISSN (O) - 2582-1008 July 2021 | Vol. 3 Issue. 1 www.ijarw.com export to temperate countries. Coffee ranks as one dioxopurine. Thus pure anhydrous caffeine is a of the world's major commodity crops and is the powder with white odorless and it has a melting major export product of some countries [1] point of 235–238 °C. At room temperature, caffeine is moderately soluble in water (2 g/100 Coffee beans purchased are produced from two mL), but it is more soluble in boiling water (66 different species of the Coffea genus: Coffea g/100 mL). It is also moderately soluble in ethanol arabica and Coffea canephora syn. Coffea robusta. (1.5 g/100 mL). It is weakly basic (pKa = ~0.6) Traditionally, C. canephora, primarily from African requiring strong acid to protonate it. However, origins, was the dominant component in most caffeine does not contain any stereogenic centers coffee blends available in Belgium/Luxemburg, and hence is classified as an achiral molecule. France, Portugal, and the UK, while most blends available in Scandinavia, Austria, Switzerland, Moreover, the xanthine core of caffeine contains Germany, Italy, and Spain incorporated a much two fused rings, pyrimidinedione, and imidazole. higher proportion of C. Arabica[2]. Wherever, the pyrimidinedione in turn contains two amide functional groups that exist Nowadays, due to its pleasant taste, aroma, predominately in a zwitterionic resonance form stimulant effect, and health benefits, coffee is one where the nitrogen atoms are double bonded to among the most widely consumed beverages their adjacent amide carbons atoms. Hence all six throughout the world includes Rwanda country. of the atoms within the pyrimidinedione ring Both species of coffee present a rich source of system are sp2 hybridized and planar. Therefore biologically active compounds such as caffeine[3]. the fused 5,6 ring core of caffeine contains a total Caffeine is defined as a xanthine alkaloid of ten pi electrons and hence according to Hückel's compound that acts as a stimulant in humans. It is rule is aromatic[6]. normally found in the leaves and beans of the coffee plant. In addition to that, caffeine is widely used to enhance alertness and improve performance as it acts as psychostimulant [4]. 1.2. Caffeine properties Generally, caffeine belongs among the family of heterocyclic compounds known as purines. Its systematic name is 3, 7-dihydro-1, 3, 7-trimethyl- 1H-purine-2, 6-dione; it is also known as 1, 3, 7- Figure 1.structure of caffeine trimethylxanthine, and 1, 3, 7-trimethyl-2, 6- Table 1.Properties of Caffeine General Systematic name 3,7-dihydro-1,3,7-trimethyl-1H-Purine-2,6-dione Other names 1,3, 7-Trimetylxanthine, Trimethylxanthine, Methyl theobromine. Molecular formula C8H10N4O2 SMILES O=C1C2=C(N=CN2C)N(C(=O)N1C)C Molar mass 194.19 g mol−1 Appearance Odorless, white needles or powder 1.3. Biosynthesis of Caffeine then theobromine, later being the penultimate precursor of caffeine synthesis. It is therefore, to Caffeine is normally synthesized in plants from the be readily available as a byproduct of purine nucleotides AMP, GMP, and IMP. Wherever decaffeination, caffeine is not usually chemically these in turn are transformed into xanthosine and synthesized. If desired, it may be synthesized from IJARW1495 International Journal of All Research Writings 2 © IJARW | ISSN (O) - 2582-1008 July 2021 | Vol. 3 Issue. 1 www.ijarw.com dimethylurea and malonic acid. The crude extract then lead to the formation of 7- of Escherichia coli catalyzes the removal of the methylxanthine.then; caffeine is formed in vitro Ribose moiety from 7-methyl xanthosine; and from the conversion of xanthosine [7]. Figure 2.Caffeine Biosynthesis 1.4. Effect of Caffeine on Health lowered birth weight and smaller head circumference when it is > 300 mg per day [6]. Although caffeine is commonly assimilated for the enhancement of alertness and the performance As for caffeine’s effect on children, one study improvement, its use should be avoided by assessed the physiological effects of caffeine on pregnant women, children, and persons with young children ages 7 to 9 years old. The study cardiovascular disease and anxiety disorders. For demonstrated that, in both boys and girls, caffeine instance, studies have demonstrated a link can produce a lower heart rate and higher blood between caffeine ingestion and risk elevation of pressure. Caffeine may also affect sleep patterns miscarriage. One study supporting these in teenagers. Because of caffeine’s adverse effects, determination states that the risk of miscarriage some people may choose to control and/or reduce is doubled when the ingesting > 300 mg per day their caffeine intake. Caffeine is most commonly of caffeine compared to women whose caffeine taken through coffee, and therefore, many intake is < 151 mg per day. Another study showed websites suggest switching to tea in order to limit that caffeine consumption is associated with daily caffeine intake[4]. IJARW1495 International Journal of All Research Writings 3 © IJARW | ISSN (O) - 2582-1008 July 2021 | Vol. 3 Issue. 1 www.ijarw.com In addition to its most recognized stimulatory seeds are decaffeinated when they are still green. effect on the central nervous system, caffeine also However, many methods can remove caffeine affects several other tissues and organs, including from coffee, but all involve either soaking the the kidney, where it increases water and mineral green seeds in hot water (often called the "Swiss urinary excretion .Thus, the acute ingestion of water process" or steaming them, and then using caffeine in amounts increases the urinary solvents to dissolve caffeine-containing oils: excretion of calcium, magnesium, and sodium for Certain extracting solvents are including organic at least 3 h approximately after consumption. solvents such as dichloromethane (DCM); Water Renal conservation over 24 h after a caffeine load Extraction will be adopted as other polar my appear insufficient to offset the caffeine- molecules such as tannins which will also be induced calcium and magnesium losses[8]. extracted in the process; Supercritical Fluid CO2 and other recent methods of extracting caffeine Coffee is most well known as a beverage, it is also including High-Performance Liquid used as an ingredient in cooking.