| Nitrite is widely used in meat products because of its ability to inhibit the growth and reproduction of Clostridium botulinum,formate special color and flavor of meat products and prevent lipid oxidation.But residual nitrite into the human body through food intake will oxidize hemoglobin to methemoglobin,causing methemoglobin.Nitrite is harmful to human for carcinogenicity nitrosamines,which are produced from nitrosation reaction.Western-style ham was chose as test material,the effects of antioxidants,different cooking and storage conditions on meat qualities and nitrite conversion pathways in ham were investigated by measuring the meat quality indexes and nitrite contents of related conversion pathways.The main results and conclusions were as follows:1.The effects of antioxidants on meat qualities and nitrite conversion pathways in western-style ham: Fresh pig meat was chose as test material for the production of western-style ham,which was respectively added ascorbic acid,sodium ascorbate,isoascorbic acid and sodium isoascorbate before cooking.The changes of nitrite,N-nitrosamine,red value and lipid oxidation were studied.Effect of antioxidant on nitrite conversion pathway was researched by measuring the contents of nitrizc oxide analyzed by nitric oxide detector,nitrate and nitrite analyzed by HPLC.The result showed that the antioxidants all could significantly reduce residual content of nitrite and N-nitrosamine content,improve the red value and delay lipid oxidation,sodium isoascorbate was the best.When the dosage of sodium isoascorbate was 500 mg/kg,the residual content of nitrite was 26.24 mg/kg,the degradation rate was72.49%,N-nitrosamine content was 1.05 ?g/kg,decreased 69.39%,a* value increased13.49%,TBARs decreased 60.00%.Sodium isoascorbate could inhibit nitrite disproportionation reaction,but significantly promoted the degradation reaction,resulting in a significant decrease in the content of residual nitrite.After the addition of 500 mg/kg sodium isoascorbate,the nitrite content in the disproportionation reaction decreased from 27.33% to16.67%,the nitrite content in the degradation reaction increased from 8.67% to 65.33%,and the residual content decreased from 64.00% to 18.00%.2.The effects of cooking factors on meat qualities and nitrite conversion pathways in western-style ham: Fresh pig meat was chose as test material for the production of western-style ham,the changes of the residual content of nitrite(Y1),N-nitrosamine content(Y2),red value(Y3)and lipid oxidation(Y4)were studied under the different sodium nitrite content(X1),curing time(X2),cooking temperature(X3)and cooking time(X4).The result showed that the formulas were Y1=96.841+0.114 X1-0.422 X2-0.695 X3-0.140 X4,Y2=-0.753+0.004 X1-0.023 X2+0.029 X3+0.004 X4,Y3=4.086+0.021 X1+0.068 X2+0.036X3+0.006 X4,Y4=-0.078-0.001 X1+0.001 X2+0.003 X3+0.001 X4.Increasing sodium nitrite content,lengthening curing time and cooking time mainly promoted the disproportionation reaction,rising cooking temperature mainly promoted nitrite degradation reaction.3.The effects of storage conditions on meat qualities in western-style ham: New productions of western-style ham were stored at 4 ? and 25 ?.The changes of nitrite,N-nitrosamine,colour and lipid oxidation were studied under the storage conditions within 12 days.The result showed that the residual contents of nitrite significantly decreased with the increase of storage time.Nitrite reduction at room temperature was more rapid than under refrigeration.The N-nitrosamine contents increased.After storing 12 days,the N-nitrosamine content under refrigeration was less than at room temperature.Red value decreased during storage and that stored at room temperature changed more significantly.The levels of TBARs gradually increased with the increase of storage time.There were significant correlations between the residual content of nitrite and the qualities in the western-style ham during storage. |
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