Effect of tomato paste and nitrite level on processing and quality characteristics of frankfurters

Fourteen treatments of frankfurters (18% fat) were produced with two levels of sodium nitrite, 0 and 150 mg/kg (0.015%), and seven levels (0%, 2%, 6%, 8%, 12% and 16%) of tomato paste with 12% soluble solids The higher the tomato paste level the higher the preference of consumers for frankfurters based on their colour. Frankfurters with 16% tomato paste had a sour taste while those with 12% tomato paste were the most acceptable. In a 2nd experiment three treatments of frankfurters (18% fat) were produced with 0, 50 and 100 mg/kg of sodium nitrite and 12% tomato paste and a fourth (control) with only 150 mg/kg sodium nitrite. Treatments with 12% tomato paste had lower (p < 0.05) pH values and residual nitrite, and higher (p < 0.05) thiobarbituric acid values, lightness and yellowness than control. Frankfurters with reduced levels of sodium nitrite (50 and 100 mg/kg) and 12% tomato paste had the highest (p < 0.05) redness. Storage time affected (p < 0.05) all quality attributes. The nitrites added to frankfurters can be reduced from 150 mg/kg to 100 mg/kg in combination with 12% tomato paste without any negative effect on the quality of the product.