## 3 Results and Discussion  
### GC-MS Results  
A number of changes correlated with the increasing temperatures that occurred during the roasting process in both types of coffee roaster [5]. The first drying stage proceeded in a temperature range of 20-130 \({}^{\circ}\)C. During this stage, the coffee beans became lighter. In the next stage (130-140 \({}^{\circ}\)C), the coffee beans began to swell and turned yellow due to the non-enzymatic browning process. The third stage (140-160 \({}^{\circ}\)C) was associated with a significant increase in the volume of the coffee beans and the number of micropores. Small cracks formed on the surface and the coffee beans became brittle. This was the first step in the generation of the aroma and volatile compounds. The subsequent step (160-190 \({}^{\circ}\)C) was characterized by progression of the Maillard reaction and other pyrolysis reactions into the internal dry structure of the coffee beans [23]. In the final stage (190-220 \({}^{\circ}\)C), the coffee beans emitted smoke and the volatilized carbon dioxide induced an increase in their porosity. The final stage yielded the typical coffee aroma produced by the main volatile compounds identified in the analysis [35; 36; 37].  
The chromatographic analyses determined approximately 20 main volatile compounds (Table 1 and Figure S1). Different percentage contents were determined in the coffee beans originating from the five regions, but the major differences were revealed between the CCR and CC roasting methods.  
In general, as shown by reports in the literature, over 800 volatile compounds can be determined in coffee beans, with approximately 20 compounds containing a pyridine ring, including methyl, ethyl, acetyl, and vinyl derivatives [37; 38]. Pyridines are generated through trigonemline degradation reactions. They have an unpleasant plant-like and bitter odor that indicates their presence in products. For instance, 2-methylpyridine has a characteristic hazelnut odor, while 3-ethylpyridine has a buttery, plant-like, and caramel aroma. A stronger roasting degree is usually associated with higher pyridine content [13]. In the present study, the amount of pyridine was higher, which was probably related to the method of heat transfer to the coffee beans in the CC roaster rather than the roasting degree. The hot exhausts in the roaster without the exchanger had a direct impact on the coffee beans, inducing the generation of a higher content of pyridines through the activity of gas tar produced in the process of combustions of the fuel used to ensure high temperature in the roasting process. Another compound present in greater amounts in the Brazil Santos, Guatem Comal, Costa Rica La Pastora, Ethiopia Sidamo, and Peru El Palto Organic coffee beans was 2-oxopropanal (aldehyde), which is a product of oxidation of primary alcohols. Aldehydes most often give coffee a note of fruit aroma and flavor. However, while the presence of, e.g., pyridine in the aroma profile of coffee beans is natural, increased amounts generated when roasting coffee bean in the CC roaster, relative to CCR, is regarded as a defect [14]. In excess it is harmful to the human organism and, in extreme cases, can lead to intoxication manifested by such symptoms as stupor, headache, nausea, and reduced appetite. Late symptoms include abdominal pain and pulmonary embolism. This chemical is also currently being investigated for its potential carcinogenicity. The available studies have not provided a convincing answer to the issue of probable carcinogenic effects of pyridine in the human organism; however, some tests carried out on animals confirm such an effect [12; 39; 40].