## 3 Results and Discussion
### Correlations Between Volatile Compounds and Flavor Sensory Attributes  
The partial least squares regression (Figure 4) was constructed with the cheese samples (\(n=12\)) using only the significant flavor sensory variables (\(\Upsilon\), \(n=11\)) and significant volatile compounds (\(\Upsilon\), \(n=45\)) in order to analyze the correlations between flavor sensory attributes and volatile compounds. The first three PLS factors explained 74% (Xcum) and 54% (Ycum) of the variance in the data. According to the results of Figure 4, Salers cheeses can be clearly distinguished from Cantal cheeses along the first axis of the PLS biplot. Figure 4: Partial least squares regression loading for t1 and t2 performed on significant volatile compounds (\(\Upsilon\); \(n=45\); red point) and sensory flavor attributes (\(\Upsilon\); \(n=11\); blue point) and cheese samples (green capital letters, \(n=12\)). Blue circle includes samples from Salers category and orange circle includes samples from Cantal category. Number for variables (VOCs) refers to opposite table. PDO Salers cheeses were distinguished from PDO Cantal cheeses by their more intense flavor and sensory attributes (mushroom/animal odors, ammonia/vegetal/atypical/animal aromas and sour taste) and by their highest relative quantity of thirty-three VOCs. Among them, phenylethyl alcohol (44), butanoic acid, 3-methyl (36) and isopentyl hexanoate (30) were positively correlated with the aroma of ammonia describing H_Salers cheese. A vegetable aroma was positively correlated with ethyl acetate (1), ethanol (3), isobutyl acetate (5), butanoic acid, ethyl ester (6) and propanoic acid, 2-hydroxy-, ethyl ester (23). The mushroom odor specifically described the H_Salers cheese, which was correlated with phenylethyl alcohol (44), isopentyl hexanoate (30) and 3-methyl- butanoic acid (36). Generally, this odor could be associated with the specific molecule 1-octen-3-one, but in this case, this volatile compound was not detected [4]. Alcohols can generate a wide variety of aromas in cheese, for example, alcoholic, fruity, green, floral, rose, malty, honey, herbaceous, sweet, caramel and others [61; 62]. In contrast (for negative values along the first axis of the PLS biplot), PDO Cantal cheeses were clustered in the PLS biplot due to their flavor attributes (bitter and pungent tastes and nutty aroma) and twelve VOCs. Only the bitter taste attribute was correlated with volatile compounds. Indeed, a bitter taste was clearly correlated with acetoin (20), nonanal (26), trimethyl-pyrazine (27), 2-hydroxy-3-pentanone (25) and 2,3-pentanedione (9), which describe A_Cantal_cheese in particular. Such correlations were unexpected but revealed interesting synergetic sensorial interactions in Cantal cheeses' taste. On the one hand, bitterness can be generally linked to the peptide and amino acid compositions, and on the other hand, nonanal compounds were characterized by green grass and herbaceous aromas. Indeed, it has been shown that straight-chain aldehydes were very unpleasant when their concentrations exceeded certain thresholds. It could be supposed that high levels of the grass flavor of nonanal compounds and their association with other volatile compounds could increase the intensity of the bitter taste in Cantal cheese. We can suppose a similar phenomenon with nonanal compounds compared to ethyl hexanoate compounds (another aldehyde). Indeed, [PERSON] et al. (2019) [63] identified a correlation between ethyl hexanoate and bitterness in Swiss cheese. Normally, at a low concentration, ethyl hexanoate carries a fruity flavor note in Swiss cheese. However, when the concentration increases, ethyl hexanoate gives a bitter perception in Swiss cheese. It could be very interesting to conduct a further analysis to quantify the volatile compounds and determine the odor activities' values [62] and identify those contributing to the aromas of Cantal or Salers cheeses.