# Antioxidant Activity of Coffee Components Influenced by Roast Degree and Preparation Method
## 3 Results and Discussion
### Antioxidant Activity of Coffee Extracts
Taking into account the values per portion corresponding to an espresso shot, an inverse relationship is visible--espresso exhibited higher antioxidant activity in the method based entirely on the SET mechanism (Table 3). The values for the ABTS method did not meet statistical assumptions, and non-parametric analysis did not indicate differences between analyzed samples. In a method based entirely on the HAT mechanism (CBA method), espresso brews showed a capacity higher than the moka brews to scavenge free radicals and protect crocin from degradation (Table 4). It is worth noting that the medium-roasted espresso brew showed even higher activity than bean extract, which may be due to better extraction of active compounds during its preparation. As mentioned before, the method using the autoxidation of linoleic acid is based on a combined mechanism with a predominance of HAT. Due to the specific conditions of this technique, i.e., the use of compounds found in the human body, the reaction temperature and pH value of the environment, it is said that this method best reflects the conditions of the oxidation process in the human body. These method's results are similar to those obtained with the CBA method. When the results of those two methods were converted based on standard solutions and presented in mg of Trolox per portion, the influence of the preparation method was ambiguous--in the CBA method, moka brews were significantly different from espresso brews, while in the method using the autoxidation reaction, both espresso samples were similar to the respective moka brews (Table 4). As indicated by statistical analysis, the effect of the degree of roast in those methods was unclear as well. Infusions commonly referred to as \"coffee\" are prepared in many ways today. The choice of method is mainly influenced by the taste preferences of consumers. Two methods were used in the research, in which increased pressure is used--espresso and the method with the use of a moka pot. The dependence of the antioxidant properties on the method of preparing the brew is not clear. In the case of SET-based methods, the changes in the properties tested can be easily explained by the different characteristics of the preparation methods, mainly different pressure and coffee:water ratio, resulting in a different volume of final infusions. The research of [PERSON] et al. [17] confirms the supposition about the importance of the preparation method--comparing filtered coffee and espresso, the latter had a higher activity per mL of infusion each time. In the research by [PERSON] et al. [39], espresso brews showed lower activity than drip coffee, and brews prepared with aeropress were the most active. In that research, however, espresso brews were prepared with a different coffee:water ratio than is normally established [29]. Even so, it was proven that higher pressure used during the preparation of the brew might improve the extractability of active compounds from coffee beans. The results, expressed in mg of Trolox per portion, also indicate that the common information presented to consumers about moka brews being comparable to a specific number of espresso shots is misleading. When using the methods based on the HAT mechanism, espresso once more showed higher antioxidant activity; however, no significant effect of brew preparation was seen after conversion of the results using standard solutions. It might indicate that in those methods, a nonlinear dependency of activity occurs. Furthermore, the phenolic profile obtained by different roasting and