Process optimization of ultra-high pressure treatment of grapes: Effects on the phenolic composition of red wine grapes from the Hexi Corridor region (China)

Abstract

This research evaluated the impact of ultra-high pressure (UHP) treatment on the phenolic compounds in red wine grapes. Grapes were subjected to varied conditions—specifically differences in applied pressure, pressure holding time and temperature—to ascertain the most effective treatment parameters. Optimal conditions were identified as an applied pressure of 407 MPa, a holding time of 25 min, and a holding temperature of 26 °C. UHP treatment noticeably disrupted the cell structure and diminished PPO activity in the processed samples. The impact of optimal UHP treatment on Cabernet Sauvignon and Merlot's physicochemical indices and phenolic contents was investigated using multivariate statistical analysis. Results highlighted that UHP treatment significantly increased phenolic compounds. Among these, anthocyanins, flavonols, flavanols and stilbenes showed the most pronounced increase. Furthermore, the Cabernet Sauvignon samples responded more favorably to UHP treatment than the Merlot samples.