摘要
This study investigated the relationship between the level of iron chemical forms and the initial raw meat pH values during cooking, including the effect of the sodium nitrite presence. The pH value, the heme iron （HI） and non-heme iron （NHI） concentrations were measured on one ground portion of five loin, five masseter, five semimembranosus, five neck muscles and five shoulder muscles. Afterwards, all raw meats were halved and mixed with NaCl （2%）, ascorbic acid （0.05%） and 0 mg/kg of sodium nitrite （mix1） or 150 mg/kg of sodium nitrite （mix2）. Both mixes were divided into 50 g-portions, vacuum packed in cryovac bags and cooked in thermostatic bath up to F （10, 71 ℃） = 30 minutes at the core. The NHI and HI concentrations were determined both on the cooked meats and on the juice lost during cooking. The cooking process caused the release of NHl and H1 on all cooked sample juices. The HI overall percentage was significantly lower than raw meat one （P 〈 0.005） and the NHI significantly higher （P 〈 0.005） in all cooked mix 1. The raw and cooked HI percentage variances depended on the pork meat pH values （ra = 0.70）. The overall HI percentage was unchanged respect to raw meats on cooked mix 2, while the NHI amount was not quantitatively estimated. These results emphasized the role of sodium nitrite on tying up NHI in the cooked meats and safeguarding the oxidative stability of cooked meat products.
