# Profiling Croatian Whisky Using GC/MS-MS and UHPLC-QTOF
## 3 Results and Discussion
### Aromatic Profile of Croatian Whisky Determined by SPME-GC-MS
#### 3.3.4 Influence of Microflora on Whisky Flavor  
In whisky production, there is no boiling stage during word production, resulting in 'non-sterile' conditions for fermentation. This allows bacteria and other microflora to develop throughout fermentation from the local environment or raw materials [47; 48; 49]. These microorganisms, along with the _Saccharomyces_ yeast strain used, significantly influence the flavor profile of the fermented word, known as wash, once fermentation is complete. Comprehensive studies on bacterial communities in distillery settings reveal that species of _Lactobacillus_ are dominant, likely due to its ability to survive at high alcohol concentrations, low pH, and anaerobic conditions [50]. Although these bacterial cultures are well studied, their specific impact on the flavor characteristic of the new-make spirit remains poorly understood. Certain metabolic pathways of _Lactobacillus_ can form succinic acid from lactic or citric acid and contribute to the decarboxylation of cinnamic acids. Bacterial production of these metabolites can have a significant impact on the flavor and aroma profile of distilled washes [51; 52]. In analyzed samples, several acids which can be connected with production of _Lactobacillus_ metabolism were detected, including citric acid, malic acid, succinic acid, ascorbic acid, gluconic acid, tartaric acid, and maleic acid. Citric acid, for example, a natural organic acid found abundantly in citrus fruits, contributes to the freshness and acidity of whisky. It contributes to the overall flavor profile and adds a depth to its character [1; 23]. Malic acid, commonly found in apples and other fruits, can contribute to the complexity of the flavor with a subtly sour taste. It originates from raw materials such as malted barley and can add a touch of tartness to the whisky, although it may partially break down during fermentation. It also serves as a distinguishing factor for pattern recognition between brandies and whiskies [1; 23; 31]. Succinic acid plays an important role in shaping the flavor profile of fermented beverages, adding to their overall mouthfeel an umami taste. It is commonly found in whisky as a common organic acid formed during fermentation [1; 14; 23; 53]. Ascorbic acid, or vitamin C, serves as an essential antioxidant in whisky, influencing flavor through the intricate interplay of its degradation products [1; 33]. Gluconic acid is produced from the oxidation of glucose, contributing to a mild acidity and potentially enhancing sweetness. Its impact on flavor is not as substantial as other acids. Furthermore, its presence may result from the breakdown of glucose during fermentation or from oxidation processes during maturation. Tartaric acid, one of the primary acids in wine, can also be found in whisky, contributing to its acidic taste profile [1; 31]. Maleic acid is a less common acidic compound that may be present in whisky, potentially influencing its tartness and flavor complexity. It is not typically present in whisky, but it is more commonly associated with wines, especially those that have undergone malolactic fermentation [37]. Gluconolactone, a by-product of oxidative processes, may also be found in whisky. As a compound resulting from the oxidation of glucose, gluconolactone brings a gentle sweetness and can influence the acidity of whisky through hydrolysis into gluconic acid [54].