## 3 Results and Discussion
### Volatiles Evaluation  
The evolution of volatile compounds in chokeberry juices were identified using SPME GC/MS analysis during fermentation of chokeberry juice at 0 h, 48 h, and during fermentation at 4 \({}^{\circ}\)C (Table 4). Statistical analysis was performed between the concentrations (\(\mu\)g/g) of each volatile. Alcohols, aldehydes, organic acids, esters, and ketones were the predominant groups of compounds identified in all the time periods, as also detected in most bacterial fermented or unfermented fruit juices [8; 10; 44]. Most of these volatiles have been identified in chokeberry juices/fruit or other substances fermented by lactic acid bacteria juices or produced through the lactic acid fermentation process. Specifically, 78 compounds were determined in the unrefmented juice (28 alcohols, 7 aldehydes, 18 ketones, 7 esters, 6 organic acids, and 12 other compounds), while after 48 h of fermentation 55 compounds were identified (23 alcohols, 4 aldehydes, 13 ketones, 4 esters, 5 organic acids, and 6 other compounds) as presented in Table 4. Esters and alcohols were the major flavor volatile compounds detected in fermented juices during fermentation at 4 \({}^{\circ}\)C. It is noteworthy that during the last week (fourth) of fermented juice at 4 \({}^{\circ}\)C., 70 compounds were identified (26 alcohols, 3 aldehydes, 17 ketones, 6 esters, 11 organic acids, and 7 other compounds). Alcohols, aldehydes, and ketones were the predominant groups determined regarding their total concentration in fermented chokeberry juice, while organic acids surpassed the total concentration of aldehydes in the fourth week of storage. As reported in previous studies, alcohols are important aromatic compounds detected in juices fermented by LAB. In specific, a small content of alcohols can pose a significant effect in the aromatic profile of fruit juices, as they can provide a slight aroma and in parallel pose as solvents for other aromatic volatiles detected in fruit juices [29]. In the present study a significant variety of alcohols was identified at all time periods of fermentation at 4 \({}^{\circ}\)C, providing their aromatic effects. More specifically, the volatile compounds determined in chokeberry juice in all time periods included: 3-methyl-1-butanol, 1-hexanol, (2E)-2-hexen-1-ol, benzyl alcohol, phenylethyll alcohol, 2-methylpropan-2-ol, 2-methylbutan-2-ol, 2-methyl-1-propanol (alcohols), 4-methyl-benzenemethanol benzaldehyde, 4-methylbenzaldehyde (aldehydes), 4-methyl-2-pentanone, 3-hexanone, 2-hexanone, 3-penten-2-one, 4-methyl-3-penten-2-one,  
Figure 1: ABTS\(\bullet\)+ radical scavenging capacity (**a**) and ferric reducing power (**b**) of unfermented and fermented chokeberry juice at 30 \({}^{\circ}\)C for 48 h and during storage (4 \({}^{\circ}\)C for 4 weeks). 5-methyl-3-hexanone, 4-methyl-2-heptanone (ketones), ethyl acetate and methyl benzoate (organic esters), hexanoic acid (organic acids), eucalyptpol, and terpinen-4-ol [44; 45; 46; 47; 48]. The outcome provided by these identified compounds highlights the stability of the product, as the high content of volatiles was retained even at the fourth week of fermentation at 4 \({}^{\circ}\)C (Table 4).