Preservation of paste obtained from Picual green olives by high hydrostatic pressure treatment

Olive paste can be a valuable source of phenolic compounds with antioxidant activity. High hydrostatic pressure (HHP) treatment (600 MPa, 8 min) was tested for the preservation of olive paste obtained from Picual unfermented green olives, a variety known for its high content of phenolic compounds. Microbiological load (total aerobic mesophilic counts, yeasts, and moulds), and antioxidant activity were measured during one-month refrigeration storage. At the end of the storage period, control samples maintained 27% of their initial antioxidant activity, showed browning, and had microbial loads (ca. 105 CFU/g) composed mainly of yeasts and moulds, while samples treated with HHP preserved 79% of their initial antioxidant activity, kept green colour and had no microbial counts. These results showed the potential of HHP treatment at 600 MPa for 8 min for the preservation of olive paste with strong antioxidant activity.