Use of high hydrostatic pressure (HHP) to obtain an ingredient rich in bioactive compounds from cv. Tempranillo red pomace

Abstract

With the aim to obtain an ingredient rich in bioactive compounds to be used in meat products, a red grape pomace (RGP) cv. Tempranillo, was subjected to the application of different hydrostatic high pressure (HHP) treatments: i) 600 MPa/1s; ii) 600 MPa/300s and two others treatments of 2 cycles of HHP, iii) 2 cycles of 600MPa/1s and iv) 1 first cycle of 400 MPa/1s and second cycle 600 MPa/1s. The microbiological population and polyphenoloxidase activity (PPO) of treated RGP was studied immediately after the treatments and at 270 days after the treatments at temperatures of 4 and 20 ºC respect a control sample untreated. The treatments significantly reduced the microbial population; the effect of HHP3 and HHP4 (two cycles) did not differ from those of HHP1 and HHP2 (1 cycle). Phenolic compounds (anthocyanins, flavanols, flavonols, phenolic acids and stilbenes) were extracted from GRP, identified and quantified by HPLC. The values of all these phenolic families were maintained immediately after HHP with exception of a decrease of anthocyanins in HHP3. However, the HHP treatments did not affect the polyphenoloxidase enzyme, since the phenolic compounds were notably reduced during storage although phenolic compounds were better well-preserved at refrigeration than at room temperature.