# Quantitative Analysis of Caffe in Roasted Coffee: A Comparison of Brewing Methods
## 1 Introduction  
Coffee is one of the most consumed beverages in the world, and its production and consumption are steadily increasing. It is estimated that the world's coffee consumption was 173.1 million bags (about 10.386 billion kilograms) in the years 2022/23 [1, 2]. Furthermore, in 2022, coffee ranked as the 104 th most traded commodity globally, accounting for approximately 0.19% of total world trade [3]. Coffee is characterized by its unique taste and intense aroma. In addition, it contains many valuable bioactive compounds: caffeine, chlorogenic acid, organic acids, melanoidins, and trigonelline, and due to the presence of these compounds, it can have a beneficial effect on human health [4, 5, 6]. Coffee consumption may reduce the risk of developing several chronic diseases, including hypertension (by 7%) [7], metabolic syndrome (by 13%) [8], type 2 diabetes (by \(11\%\)) [9], nonalcoholic fatty liver disease (by 29%) [10], chronic kidney disease (by 14%) [11], Alzheimer's disease (by32%) [12], liver cancer (by 35%) [13; 14], oral and pharyngeal cancer (by 31%) [15], and death from various causes (by 7-12%), particularly gastrointestinal and cardiovascular diseases (by 22-59%) [16]. Studies have analyzed the mechanisms responsible for the beneficial effects of coffee on the human body and have suggested that one of them may be the reduction of oxidative stress and inflammation. A recent literature review confirmed that coffee consumption improves biomarkers for these processes in healthy individuals and those at increased risk of cardiovascular disease [17]. Similarly, the neuroprotective effects of coffee have been associated with a reduction in oxidative stress and inflammation [18]. The association between coffee consumption and the risk of developing chronic diseases and understanding the mechanisms of its beneficial effects require further research. The authors point out that it is crucial to analyze the effects of the individual coffee compounds, taking into account their potential synergistic effects. The variability of the chemical composition of coffee infusion remains a significant challenge [18]. Studies have shown that the beneficial effect depends on the number of cups of coffee consumed and may be related to caffeine content. Caffeine is a purine alkaloid with the chemical name 1,3,7-trimethylxanthine. It consists of a xanthine core (a purine derivative) with three methyl groups attached to nitrogen atoms at positions 1, 3, and 7. Caffeine is primarily absorbed in the small intestine, with absorption occurring within approximately 30-45 min. Caffeine metabolism occurs mainly in the liver by the enzyme CYP1A2, which belongs to the cytochrome P450 system. This process leads to the formation of the dimethylxanthines--paraxanthine, theobromine, and theophylline (Figure 1). These metabolites are then further degraded and removed from the body in the urine [4; 19; 20]. According to the European Food Safety Authority [21], daily caffeine intake from all sources for adults should not exceed 400 mg, while for pregnant and lactating women, it should not exceed 200 mg. Furthermore, the World Health Organization (WHO) recommends that pregnant women who exceed a daily intake of 300 mg of caffeine should reduce their consumption to minimize potential health risks [22]. There are no conclusive studies on the adverse effects of excessive caffeine consumption, which does not exclude the possibility of their occurrence [21; 23]. Monitoring the content of this compound is important to prevent excessive consumption and minimize potential adverse health effects. Coffee is a major source of caffeine in the diet due to its high alkaloid content compared to other beverages and products [21]. Several studies analyzed the impact of various factors,  
Figure 1: The structure of caffeine and its main metabolites. such as the degree of coffee bean roasting, on the content of bioactive compounds, aromatic profiles, volatile compounds, color, and structure [24; 25; 26].