## 3 Results and Discussion
### Volatile Aroma Compounds
#### 3.2.1 Terpenes  
Terpenes originate from grapes and are considered among the leading carriers of varietal aroma, especially in wines containing higher concentrations, where they play a significant role in determining varietal typicity. Monoterpenols, such as geraniol, citronellol, nerol, ho-trienol, and especially linalool, are the most relevant terpenes in wine in sensory terms, imparting positive floral and fruity notes [26]. Several previous reports emphasized a significant contribution of linalool to Malvazija starska varietal aroma, with concentrations repeatedly higher than its odor detection threshold [27]. Although it is generally considered that terpenes are less influenced by fermentation parameters, the enzymatic activity of yeast can influence their behaviour during fermentation and their composition in the final wine, principally by affecting the release of their free volatile forms from the corresponding glycosides [28]. Moreover, terpenes undergo numerous interconversions during fermentation, which can also be affected by the yeast species [29].  
Linalool was the only major monoterpenol identified in this study. The highest concentration was found in the must inoculated with _P. kluyveri_ yeast (Table 1, Figure S1). Several studies reported limited or no effects of _P. kluyveri_ in sequential fermentation on the content of total terpenes when compared to pure _S. cerevisiae_ inoculation [10; 15], presumably because of its limited \(\beta\)-glucosidase activity [30]. However, the concentrations of particular monoterpenes, such as ho-trienol, were found to be positively affected [10].  
The lowest concentration of linalool, although not significantly different from that found in some other treatments, was found in the control _S. cerevisiae_ must, which was in line with the relatively low \(\beta\)-glucosidase activity of this commercial _S. cerevisiae_ (exex-_bayanus_) strain, as shown earlier [31]. Other yeast species investigated in this study were previously shown to increase the content of certain terpenes in sequential or co-inoculations compared to _S. cerevisiae_ monoculture.  
[PERSON] et al. [11] recorded an increase in \(\alpha\)-terpineol, ho-diendiol I, and endiol concentrations after sequential fermentation with _T. delbrueckii_ in red wine, while [PERSON] and [PERSON] [32] observed an increase in linalool and a decrease in citronellol and geraniol concentration after a similar experiment with the same yeast. Linalool concentration increased after _T. delbrueckii_ monoculture inoculation in the early phase of fermentation (2-3% _v/v_ ethanol), as reported by [PERSON] et al. [22]. In this work, early fermentation _T. delbrueckii_ must contained the lowest concentration of geranyl acetate among all the treatments, as well as a lower concentration of \(\beta\)-pinene and a higher concentration of eucalypt in relation to _S. cerevisiae_ must (Table 1). _Torusyona delbrueckii_ was previously highlighted as yeast capable of inducing interconversion reactions between monoterpenes [29], so it is possible that this phenomenon also had an effect in this study.  
In previous studies, _L. thermotolerans_ inoculation exhibited a positive effect on the concentrations of nerol and 4-terpineol in monoculture [22], as well as of geraniol, farnesol, and citronellyl acetate in sequential fermentation with _S. cerevisiae_[33], implying a significant \(\beta\)-glucosidase activity. In this study, _L. thermotolerans_ did not have an effect on terpene concentrations when compared to _S. cerevisiae_ control. Similar was observed for _M. pulcherrina_ (Table 1), contrary to a previous investigation where it positively affected the content of linalool in early fermentation [22].  
The highest concentrations of several other monoterpenes, such as camphene, \(\beta\)-pinene, menthol, 6,10-dihydroxyrcenol, and geranyl acetate were found in _S. pombe_ inoculated must (Table 1, Figure S1).