## 3 Results and Discussion
### Volatile Compounds
odorant [56] and, therefore, changes in it might influence the sausage odor and flavor, which is supported by the significant correlationships with the off-odor, flavor intensity, and off-flavor (R: 0.463, \(-\)0.475, and 0.530, \(p\) = 0.004, 0.034, and 0.016, respectively). The results for hexanal and 2-phenylacetaldehyde are in line with a previous study also reporting higher values in dry-cured sausages with a grape-seed-based extract than with sodium nitrite [18]. This suggests that the grape-based products, regardless of their form (either HHP-stabilized pomace or a grape seed extract), might not provide the conditions for the sausages to develop the flavor reactions (involving, for example, lipid oxidation and fermentation) exactly as they occur in the nitrite-containing dry-cured products. Nonanal showed a different trend, with the lowest values in the Control group, the highest in the NITRASC one, and intermediate values in the pomace groups. The different trend between these aldehydes might be related to differences in the pathways leading to aldehyde generation. This compound was not identified in the only previous study that investigated the volatile compounds of dry-cured sausages with a grape-seed-based extract [18]. This compound has not been usually identified as a dry-cured meat product odorant [18; 55; 56], and, therefore, changes in it are expected to not be critical for the sausage odor and flavor. The limited direct impact of the volatile compounds of the pomace on the volatile compounds of the dry-cured sausage is in line with the sensory results, which did not show any difference between the Control group and the groups with pomace in the odor and flavor traits (Table 6). With respect to the four compounds different between the groups (Table 5) and not identified in the pomace (Table 6), two of them (3-hydroxybutan-2-one and 2,3-butanediol) are generated through carbohydrate metabolism, whereas the other two (\(\alpha\)-phellandrene, \(\alpha\)-caryophyllene) are species constituents. 3-Hydroxbutan-2-one and 2,3-butanediol followed a similar trend to 2-phenylacetaldehyde and hexanal, respectively, both with the lowest values in the NITRASC group. They are likely to have been generated through microbial activity, whose effective inhibition caused by sodium nitrite might explain the low values in the NITRASC group. 2,3-Butanediol was especially abundant in the 3%Pomace group, which suggests that a high pomace content might favor the development of fermentation reactions. This suggests that it might be an indicator of detrimental reactions involving microorganisms. 2,3-Butanediol was closely related to the sensory characteristics, especially with the defective texture (0.919, \(p\) < 0.001), which suggests that it was related to undesired changes in the product. The results for 3-hydroxybutan-2-one and 2,3-butanediol are partially in line with a previous study reporting higher values for the latter in dry-cured sausages with sodium nitrite than with a grape seed extract but no differences for the former [18]. Both volatile compounds have not been usually identified as odorants in dry-cured products [18; 55; 56], which suggests a weak influence on the sensory traits. That was the case of 3-hydroxybutan-2-one (not correlated with any sensory trait), whereas 2,3-butanediol was correlated with juiciness and the defective texture (R: \(-\)0.487 and 0.917, \(p\) = 0.029 and \(<\)0.001) but not with the odor and flavor traits. \(\alpha\)-Caryophyllene had the highest values in the NITRASC group, similarly to nonanal, and the 3%Pomace group. The results suggest that some reactions during ripening, probably involving microorganisms and/or oxidation, might have depleted the initial amount of this compound in the groups with the highest pH (both variables were correlated--R: \(-\)0.699, \(p\) = 0.001).