Influence of an extract of liver on colour and shelf stability of sliced bologna

The influence of the substances present in an extract of liver on the characteristics of bologna sausage was studied in sliced, vacuum-packaged bologna stored under refrigeration for 70 days in darkness or exposed to light (180 ± 10ft-c). The extract replaced 0, 50 or 100% of the water added during formulation. The characteristics studied were colour intensity and stability, residual nitrite content, and oxidative rancidity. Colour fading was nearly non-existent in the batches stored in darkness but was more pronounced in those exposed to light, in which the rate of fading was inversely dependent upon the proportion of extract added. Nitrite loss over the storage period followed a first-order kinetic equation and was dependent upon both liver extract concentration (higher at higher extract levels) and the storage conditions (more pronounced in the batches exposed to light). The changes in the residual nitrite concentration could be attributed to its colour stabilizing action. While the 2-thiobarbituric acid (TBA) index tended to be higher at higher concentrations of liver extract, the increases were not substantial and were not dependent upon the storage period or illumination. Rancidity was not a limiting factor in the refrigerated storage of the product.