## 3 Results and Discussion
### Identification of Flavor Markers Using PLS-DA  
The differences in volatile compounds among different fermented rose beverages were revealed through multivariate statistical analysis performed using PLS-DA. The findings revealed that the model did not exhibit overfitting; the PLS1 and PLS2 explained 65.6% and 28.1% of the total variance, respectively, which can account for the differences in volatile compounds (Figure 6A). The potential flavor markers in rose beverages can be identified using the VIP score, which reflects the influence of volatile compounds on the overall flavor profile. When VIP > 1, these markers were likely to significantly influence the flavor of the samples. In Figure 6B, compounds such as eugenol, 2-methoxy-6-(2-propenyl)phenol, phenylethyl alcohol, (E)-3,7-dimethyl-2,6-ocatadienoic acid, methyleugenol, (2,2,4,4a,8a,8a)-1,2,3,4,4a,5,6,7-octahydro-\(\alpha\),\(\alpha\),4a,8-tetramethylhaphthalene-2-ylmethanol, ethyl octanoate, citronellol, 2,4-dimethylbenzaldehyde, [2r-(2,4a,8a,8a)]-decahydro-\(\alpha\),\(\alpha\),4a-trimethyl-8-methylenenaphthalen-2-ylmethanol, D-citronellol, (3,7-dimethyl-6-ocenyl)4-methylpentan-oatel, 2,4-di-tert-butylphenol exhibited VIP > 1. Among these, eugenol, phenylethyl alcohol, (E)-3,7-dimethyl-2,6-ocatadienoic acid, methyleugenol, ethyl octanoate, citronellol, D-citronellol, and 2,4-di-tert-butylphenol have OAV > 1, indicating that they can be identified as biomarkers and have important roles in influencing the flavor of fermented rose beverages. However, the aroma of food is formed through the interactions of volatile  
Figure 5: Heatmap and cluster analysis of major aroma compounds in rose beverage samples fermented with different strains. UFR: rose beverage without fermentation; LFR: rose beverage fermentation by _L. plantarum;_ SFR: rose beverage fermentation by _S. cerevisiae;_ LSFR: rose beverage fermentation by _L. plantarum_ and _S. cerevisiae_ collectively.  
compounds [16]. The flavor mechanisms of key volatile compounds in rose beverages will be further investigated in future research.  
The escalating consumer demands for premium beverages, driven by improved living standards, have accelerated product diversification in the beverage industry. While plant-based alternatives face challenges including flavor monotony, nutritional limitations, textural deficiencies, and stability concerns compared to dairy products, microbial fermentation has emerged as an effective strategy for enhancing both organoleptic properties and nutritional profiles of plant-derived beverages [81]. At present, it has become a recognized fact that the fermentation of beneficial active bacteria can effectively improve the flavor of plant-based beverages and enhance their nutritional value [81]. For a long time, the processing technology of edible roses has been single, and the economic benefits are not high, which has restricted the development of its industry. In this study, we prepared a fermented rose beverage for the first time, providing a new idea for the diversified development of roses. We also confirmed that the co-fermented rose beverage of _L. plantarum_ and _S. cerevisiae_ can not only enhance the nutritional value, but also endow the product with a special flavor. In addition, a preliminary understanding of the composition of key flavor compounds was obtained through mass spectrometry analysis. Ultimately, this knowledge will lead to more efficient optimization of the fermentation process and improved flavor and quality of functional rose beverage. Future investigations should focus on elucidating the underlying mechanisms of aroma modulation by dominant microbiota, probiotic bioactivity enhancement pathways, and systematically investigating microbial community dynamics under varied environmental parameters. These research directions will provide critical insights for valorizing rose through bioprocessing technologies and advancing sustainable development in functional beverage innovation.