Reduced nitrite levels and dietary α-tocopheryl acetate supplementation: effects on the colour and oxidative stability of cooked hams

The objective of the present study was to determine the effects of dietary vitamin E supplementation and reduced nitrite levels on the colour stability of cooked hams. Large white × Landrace pigs (male n=6, female n=6) were each subdivided into two groups (n=3) and fed an α-tocopheryl acetate supplemented diet (1000 mg/kg feed) and a basal diet (10 mg/kg feed) for a period of 10 weeks. M. semitendinosus were removed from each pig, divided into light and dark pigmented fractions, vacuum packed and stored at 4°C for 24 h. Muscles were cured with input nitrite levels of 25 and 100 mg/kg meat and were tumbled and massaged for 17 h. Samples were cooked, sliced and overwrapped in a high oxygen permeable film for a storage period of 10 days. Surface colour of hams was measured and expressed as Hunter ‘a’ values. Concentrations of α-tocopherol were significantly (P<0.001) greater in supplemented muscles compared to basal muscles for both male and female pigs. Hams manufactured from male and female supplemented pigs resulted in significantly (P<0.001) higher Hunter ‘a’ values than hams manufactured from male and female pigs receiving the basal diet. Muscles cured with 100 mg nitrite/kg meat formed products with significantly (P<0.001) higher ‘a’ values than those cured with the lower (25 mg/kg meat) nitrite level. Hams manufactured from supplemented muscles, treated with 25 mg nitrite/kg meat showed significantly (P<0.05) higher Hunter ‘a’ values than hams manufactured from basal muscles, treated with 100 mg nitrite/kg meat. Hams manufactured from female porcine muscles had significantly (P<0.001) higher ‘a’ values than hams from male muscles during the 10 days of simulated retail display. No such gender differences were observed for TBARS values.