## 3 Results
### Correlation of Instrumental Measurements with Flavor Perception  
PCA was conducted to reduce the dimensionality of the data and identify patterns based on the correlation between VOCs and the perception of flavor attributes in each fermented sample (Figure 6).  
PCA of fermented soy samples explains 85.4% of the total variance, comprising 51.8% of the first PC and 33.6% of the second PC. The presence of acetoin correlated positively with the perception of lemon taste, astringency and sourness (R = 0.9). This was attributed to samples that were fermented with YF-L02+LGG(r), which is supported by the FID results reported above. Samples that were fermented with YF-L02 were located in an opposite area of the graph to YF-L02+LGG(r) along PC1 axis. Therefore, an effect of LGG(r) when combined with YF-L02 on the perception of these flavor attributes was indicated by this analysis. In contrast, acetaldehyde, 2-pentylfuran, and 2-heptanone were positively correlated (R = 0.9) with each other but negatively correlated with the three flavor attributes mentioned above (R = \(-\)0.9). This would suggest that the presence of these volatiles was responsible for a less acidic taste. Samples fermented with YF-L01, BY-01, and YF-L01+LGG(r) clustered together around these components. This would suggest that LGG(r) did not have an effect on fermented soy flavor when combined with YF-L01, which is supported by the sensory results.  
Figure 6: Effect of different culture combinations and the VOCs they produced on the sensory perception of flavor attributes. PCA bi-plot of the first two principal components (PCs) in fermented (**A**) soy, (**B**) oat, and (**C**) coconut samples labeled by culture combinations.  
PCA of fermented oat samples explained 91.4% of the total variance, comprising 67% of the first PC and 24.4% of the second PC. All culture combinations containing LGG(r) clustered together far from their respective cultures without LGG(r), which indicated that LGG(r) had an effect on fermented oat flavor. They were close to the attributes sourness, astringency, lemon and fruity flavors. A positive correlation between them and the presence of diacetyl, acetoin and 3-methyl-thiolanone (R = 0.9-1) was found. The sweetness and oat/cereal flavor were related with the presence of acetaldehyde (R = 0.7) and acetone (R = 0.4-0.5), although the association was not significantly strong. Samples that were fermented with YF-L02 and BY-01 were located close to these components. YF-L01 was found close to ethanol and propanol and these compounds were negatively correlated to diacetyl and acetoin (R = -1), which is supported by the results obtained by FID. PCA of fermented coconut samples explained 99.9% of the total variance, comprising 57.8% of the first PC and 42.1% of the second PC. Lemon taste and sweetness were positively correlated (R = 0.9) and also with ethanol (R = 0.9) and diacetyl (R = 1). Acetoin, \(\gamma\)-nonalactone, \(\alpha\)-pinene, and 2-pentanone were also positively correlated (R = 1) and located close to the previously mentioned components. The sample fermented with YF-L02 clustered with all culture combinations containing LGG(r) around the previously mentioned attributes. This indicates that LGG(r) did not have any effect on fermented coconut flavor;when added to YF-L02. Nevertheless, an effect of LGG(r) in the perception of fermented coconut flavor when combined with YF-L01 and BY-01 was observed. The sample fermented with BY-01 was associated with acetaldehyde, which is supported by the results obtained by FID. It was negatively correlated with all components except from sweetness, although the correlation was not significant. The presence of 2,3-pentanedione was negatively correlated with the perception of sweetness and lemon taste (R = 0.9) and associated with YF-L01. This sample was the one that scored lower in lemon taste perception in the sensory evaluation.