Integral Use of Red Wine Pomace after Hydrostatic High Pressure: Application of Two Consecutive Cycles of Treatment.

The influence of applying hydrostatic high pressure (HHP) to red grape pomace cv. Tempranillo was studied to obtain an ingredient rich in bioactive compounds for the manufacture of food products. Four treatments were investigated: (i) 600 MPa/1 s; (ii) 600 MPa/300 s, and other two treatments with 2 cycles of HHP: (iii) 2 cycles of 600 MPa/1 s; and (iv) 1 first cycle of 400 MPa/1 s and a second cycle 600 MPa/1 s. Treated pomace was stored at different temperatures (4 and 20 °C). The application of two consecutive cycles had no effect on the microorganisms' inactivation compared to only one cycle. Immediately after HHP, the phenolic compounds content was maintained. However, HHP had no influence on the polyphenol oxidase enzyme (PPO), and so the phenolic compounds were significantly reduced during storage. Hence, the shelf-life of red grape pomace was significantly reduced at both temperatures, although phenolic compounds were better preserved under refrigeration than at room temperature.

Application of White-Wine-Pomace-Derived Ingredients in Extending Storage Stability of Fresh Pork Burgers.

White wine pomace, a by-product from winemaking, was stabilized after the application of thermal blanching (with the aim of deactivating the polyphenoloxidase enzyme), milling, and processing by hydrostatic high-pressure treatment (with the aim of reducing initial microbial loads while preserving phenolic compounds content). The valorized pomace (VP) ingredient was added at different proportions to pork burgers (0.5%, 1%, and 3% w/w) to improve their preservation, and the effect was compared to those produced by sulfites and with a control (without sulfites or VP). Burgers were vacuum-packed and refrigerated for 7 days. Microbiological, color, oxidation, and sensory parameters were analyzed. Neither sulfites nor VP reduced the microbial development of most microorganism groups evaluated (p > 0.05); however, both prevented coliform growth during storage (p < 0.01). The use of sulfites prevented the discoloration of burgers during storage, while VP had no effect (p < 0.001). On the contrary, VP limited lipid and protein oxidation development during storage (p > 0.05), while sulfites had no effect. Therefore, the use of VP from white wine production could have an antioxidant effect but a limited antimicrobial or color-protective effect for the preservation of pork burgers.