Effects of high hydrostatic pressure (HHP) on the protein structure and thermal stability of Sauvignon blanc wine

Protein haze development in bottled white wines is attributed to the slow denaturation of unstable proteins, which results in their aggregation and flocculation. These protein fractions can be removed by using bentonite; however, a disadvantage of this technique is its cost. The effects of high hydrostatic pressure (HHP) on wine stability were studied. Fourier transform infrared spectroscopy experiments were performed to analyse the secondary structure of protein, thermal stability was evaluated with differential scanning calorimetry, while a heat test was performed to determine wine protein thermal stability. The results confirmed that high pressure treatments modified the α-helical and β-sheet structures of wine proteins. Throughout the 60 days storage period the α-helix structure in HHP samples decreased. Structural changes by HHP (450 MPa for 3 and 5 min) improve thermal stability of wine proteins and thus delay haze formation in wine during storage.