## 4 Conclusions  
In this study, we systematically explored the effects of HHP treatment, under various conditions, on the polyphenols and volatile aromatic compounds in Marselan red wine. These findings revealed that appropriate HHP treatment significantly affected the polyphenic composition and aromatic characteristics of Marselan wine, thereby effectively enhancing its sensory quality. Notably, under HHP treatment at 300 MPa for 20 min, there was a significant increase in total polyphenol content, especially in key polyphenols such as resveratrol and protocatechuic acid. However, it is important to note that when the pressure was increased to 600 MPa, the polyphenol content decreased, possibly due to structural damage to the compounds caused by the high pressure. This suggests that moderate HHP treatment can effectively release polyphenols from wines. Furthermore, the effects of HHP were evidenced by the synergistic actions of equilibrium, [PERSON]'s principle, and microstructural ordering, which significantly impacted biomacromolecules, altering their structure and state and thereby modifying their inherent properties. Additionally, given the suboptimal deactivation of enzymes under HHP, the alterations observed in the phenolic compounds and coloration of the wine were closely linked to enzymatic activity [34]. Additionally, under the same conditions, the total amount and types of volatile aromatic compounds in Marselan wine did not change significantly compared to those in the control group. However, the ester-compound content significantly increased under these treatment conditions, bringing richer and more pronounced floral and fruity aromas to the wine. In contrast, when the pressure was raised to 400 MPa and maintained for 20 min, this increase was mainly in quantity rather than in aromatic characteristics, although the total content of volatile components did indeed significantly increase. This indicates that although higher pressures can increase the content of some volatile components in wine, they do not directly lead to changes in aroma complexity or sensory diversity. Analysis has revealed that HHP alters the composition of volatile compounds by modulating the activity of key enzymes in the aroma synthesis pathways, specifically lipoxygenase (LOX) and hydroperoxide lyase (HPL) [35]. Among various metabolic pathways for aroma, the plant-specific fatty acid metabolism pathway is especially crucial. In this pathway, LOX catalyzes the transformation of precursors such as linoleic and linoleic acids into hydroperoxides, which are subsequently converted into aldehydes, alcohols, and esters through the catalytic actions of HPL, alcohol dehydrogenase (ADH), and acyltransferase (AAT) [36]. Research has indicated that HHP has a biphasic effect on LOX: it activates the enzyme at pressures below 400 MPa while significantly inhibiting its activity above this threshold [37]. Consequently, different HHP conditions have markedly distinct impacts on the volatile components of wine. In conclusion, the optimal sensory characteristics of Marselan wine were achieved under HHP treatment at 300 MPa for 20 min. This condition effectively enhanced the aromatic profile and improved the taste. These findings further validate the potential of HHP treatment for enhancing the quality and flavor of Marselan wine. Future research will explore the effects of HHP treatment on different types of wines and their aging processes and delve into the underlying mechanisms, aiming to achieve customized quality and flavor diversity in wine. Conceptualization, Z.Y., D.Z. and Q.G. ; validation, Q.G. ; formal analysis, Z.Y. and D.Z. ; investigation, T.C., Z.Y., X.C., J.K., Y.L., B.P. and B.Y. ; writing--original draft preparation, Z.Y. and D.Z. ; writing--review and editing, Q.G. ; supervision, Q.G. All authors have read and agreed to the published version of the manuscript.