High-pressure treatment of dry-cured Iberian ham.: Effect on colour and oxidative stability during chill storage packed in modified atmosphere

Slices of dry-cured Iberian ham were pressurized at 200 and 400 MPa for 15 min and subsequently packed in two different modified atmospheres of 30% carbon dioxide or 30% carbon dioxide and 5% oxygen (both balanced with nitrogen). Non-pressurized ham slices were also packed in two different modified atmospheres and all packages were stored at 5 degrees C for 39 days in illuminated chill cabinets. Measurements of colour and oxidative stability were performed after 1, 18 and 39 days of storage. High-pressure treatments at the level of 400 MPa resulted in the highest value for the tristimulus lightness L*p-parameter during storage, reaching the maximum values after 39 days. Redness, measured as the tristimulus a*-parameter, was affected by pressure treatment, since samples submitted to treatment of highest pressure had significantly lower initial red colour. Oxygen was found to have a detrimental effect on nitrosylmyoglobin content since the extractable content was significantly lower after 18 and 39 days of storage in the 5% oxygen atmosphere. The effect of high pressure on oxidative stability was statistically significant after 39 days of chill storage with slices pressurized at 400 MPa showing the highest content in TBARS. High-pressure treatment at 400 MPa resulted in discoloration and oxidative degradation of lipids in dry-cured Iberian ham during subsequent illuminated chill storage.