## 3 Results
### Fermentative Ability of Yeast Isolated from the Apricot Microbiota  
The fermentative abilities of four yeast isolates after enrichment cultures of apricot puree, namely, _P. kudriavzevii_ L1, _H. warum_ L2, _H. pseudoguillermondii_ L3, and _H. clermontiae_ L4 were assessed on malt wort (W) and malt wort added with 5% of pasteurized apricot puree (WPP) (Figures 2 and 3). In malt wort, yeast isolates showed similar fermentation kinetics, lowering the original gravity of wort (1.057\(\pm\) 0.001) to an average final gravity of 1.0529 \(\pm\) 0.001, which corresponds to an attenuation of 7.221% \(\pm\) 0.448 and an ethanol concentration of 0.540 \(\pm\) 0.04 (% vol/vol) (Table 2). In WPP, the increase in the concentration of easily fermentable sugars (glucose and fructose), due to apricot addition, resulted in higher original gravity (1.058 \(\pm\) 0.001), the reduction of the lag phase, and an increase in ethanol production. Figure 3: Fermentation kinetics (depicted as cumulative weight loss) of yeasts isolated from apricot fruits growing in malt wort + apricot puree (WPP). Circle: _Pichia kudriavzevii_ L1; diamond: _Hansenianspora warum_ L2; triangle: _H. pseudoguillermondii_ L3; square: _H. clermontiae_ L4. Data are means \(\pm\) SD of three independent replicates. Where not visible, error bars lie below the symbols. Figure 2: Fermentation kinetics (depicted as cumulative weight loss) of yeasts isolated from apricot fruits growing in malt wort (W). Circle: _Pichia kudriavzevii_ L1; diamond: _Hansenianspora warum_ L2; triangle: _H. pseudoguillermondii_ L3; square: _H. clermontiae_ L4. Data are means \(\pm\) SD of three independent replicates. Where not visible, error bars lie below the symbols. Particularly, the average final gravity was 1.052 \(\pm\) 0.01 with an attenuation of 9.04% \(\pm\) 1.02, and an average ethanol concentration of 0.676% \(\pm\) 0.08 (vol/vol). _H. clermontiae_ L4 in WPP showed the lower fermentative power, producing 0.575 \(\pm\) 0.032% (vol/vol) of ethanol, while the other yeast species attained up to 0.741 \(\pm\) 0.02% (vol/vol) of ethanol. To better evaluate the suitability of yeast isolates as brewing strains, volatile compounds were analyzed in the fermented substrates W and WPP (Figure 4)  
In the two substrates, yeast fermentation resulted in an increase in the ester and alcohol contents, with the reduction of aldehydes, ketones, and particularly terpenes, in comparison with the unfermented samples. Specific chemical profiles were observed based on the yeast species used as a starter. In the malt wort, the three isolates of the genus _Hanseniispora_ behaved similarly, leading to the higher ester production, while _Pichia kudriavzewii_ produced the highest levels of alcohol. In malt wort added with apricot pure, _Hanseniispora clermontiae_ L4 and _Hanseniispora uavrum_ L2 confirmed their fermentative profiles, characterized by the higher and lower content of esters and alcohols, respectively. Similarly to what was observed in malt wort, _Pichia kudriavzewii_ L1 stood out for the higher alcohol and aldehyde contents. The addition of puree resulted in the production of lower levels of esters with an increase in alcohols by _H. pseudoguilliermondii_. Of note, the addition of apricot puree resulted in significant changes in the aromatic profile of the unfermented