Peaches werewashed with tapwater, cut first into slices (15mm
thickness) with a sharp stainless steel knife, and then with a cutting
grid to obtain cubes. Subsequently, these cubes were dipped into
tap water containing 200 mg/l of HClO for 2 min, drained and
dipped into an aqueous solution containing ascorbic acid (1 g/
100 ml) and citric acid (1 g/100 ml) for 2 min to prevent surface
browning and wash away the remaining HClO. The cubes were
finally drained, randomly pooled from different peaches, divided
into 8 unit lots, and packed in Cryovac BB2800 bags (Sealed Air,
Buenos Aires, Argentina-O2 transmission rate: 6e14 cm3/m2/24 h at
23 C, 101,325 Pa).
Bags were then subjected to one of the three treatments: 1)
Vacuum-packed and treated with HPP (V-P); 2) Vacuum-packed,
without HPP (V) and 3) No additional treatments, used as a Control
(C).
HPP-treated samples were previously inserted into an additional
outer bag to prevent leakages. HPP was performed in a hydrostatic
pressure equipment Stansted Fluid Power Ltd. High
Pressure Iso-Lab System model FPG9400:922 (Stansted, UK) with a
vessel of 2 l capacity and a maximum working pressure of 900 MPa.
Propylene glycol (30 ml/100 ml) inwater was used as the pressuretransmitting
medium. The conditions were 500 MPa for 5 min.
Compression rate was 5 MPa/s. The pressurization was carried out
at room temperature (20 C).