## 2 Results and Discussion  
### Concentration of Volatile Compounds in Tested Beers  
In this study, beers with the addition of mango fruit (_Mangifera indica_) in different versions were tested to assess what type of addition would have the greatest impact on the composition of volatile compounds in the final products. Five types of beer with mango and control beer without fruit were prepared. To each fruit beer, mango was added in the same amount and at the same time but in a different form (juice, pulp, raw/heatedhomogenisate, raw pieces). In the tested beers, 68 volatile compounds were identified (Table 1). They were divided into 11 main chemical groups. The largest of them were esters (28 compounds), followed by alcohols (12 compounds) and monoterenes (10 compounds). Hydrocarbons (5 compounds), acetals (3 compounds), phenylpropanoids (3 compounds), sesquiterpenes (2 compounds), aldehydes (2 compounds), acids (one compound), and ketones (one compound) were also identified. Analysis revealed one peak, which was identified as a volatile constituent, but it could not be identified (the mass spectra of the unidentified constituents and total ion chromatogram of MP are available in Figures S1 and S2). The content of five compounds identified in mango fruit, such as \(\alpha\)-pinene, camphene, p-cymene, terpinolene, and humulene, was determined in all tested beers, although the concentration of them was, with the exception of humulene, far smaller in beer without the mango addition (BC). It is worth noting that these compounds do not belong to the largest chemical groups of volatile compounds in the tested beers. The largest concentration of compounds characteristic for mango fruit and the largest amount of volatile compounds in total was recorded for beer with mango pulp addition (MP). The compound derived from mango fruit, which was found in the largest amount in MP, was terpinolene, characterized by a sweet citrusy aroma. It is a constituent of many essential oils and can be used as a flavoring agent [13]. It is a compound, which is commonly found in mango fruits, especially in cultivars grown on the American continent [14]. Its concentration was demonstrated in all tested samples, but in MP (73.162 ug/100 mL), it was far greater than in BC (0.880 ug/100 mL). Another volatile monoterpene, found in mango fruit, was camphene. As in the case of terpinolene, the largest concentration was found in MP (0.593 ug/100 mL) and the smallest in BC (0.013 ug/100 mL). Camphene is characterized by a piney, woody, and citrusy aroma [15]. P-cymene, which is also characterized by a citrusy and woody aroma, but is not a monoterene as camphene, was found in the greatest concentration in MP (2.449 ug/100 mL). \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Data:**} & \multicolumn{1}{c}{**Hessel Range**} & \multicolumn{1}{c}{**Hessel Range**} & \multicolumn{1}{  
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Extension Index**} & \multicolumn{1}{c}{**RC\({}^{1}\)**} & \multicolumn{1}{c}{**MJ**} & \multicolumn{1}{c}{**MJ**} & \multicolumn{1}{c}{**MJ**} & \multicolumn{1}{c}{**MJ**} & \multicolumn{1}{c}{**MJ**} & \multicolumn{1}{c}{**MJ**} \\ \hline
**  
Another compound identified in mango fruit was \(\alpha\)-pinene, which is a monoterpene with a characteristic piney turpentine-like aroma [16]. The greatest concentration of \(\alpha\)-pinene was recorded for MP (5.764 \(\upmu\)g/100 mL) and the smallest for BC (0.660 \(\upmu\)g/100 mL). It is worth noting that \(\alpha\)-pinene and another compound, humulene, are found not only from mango fruit but are important components of hop (_Humulus lupulus_) cones, which are used to create a characteristic beer aroma [17]. Humulene is a sesquiterpene produced by many aromatic plants, such as pine trees, tobacco, hemp, and hops, but it can also be found in the flesh and skin of mango fruit.