Polyphosphates as antioxidants in frozen beef patties

Abstract

Diphosphate, triphosphate, and trimetaphosphate, when added to minced beef (sodium salts, 0.2% or 0.5%), were each found to increase the initial product redness as a result of a more pronounced “blooming”. Beef patties with added polyphosphates showed, however, a poorer colour stability with respect to brown discoloration when followed by tristimulus colorimetric measurement during freezer storage. The tristimulus parameter Huntera, measured on the product surface, showed a linear correlation with the metmyoglobin fraction of the total myoglobin extracts, and could accordingly be used to follow the oxymyoglobin oxidation during freezer storage. Qualitatively, the oxymyoglobin oxidation rate was found to respond differently in the presence of polyphosphates in aqueous solution and in minced beef, an observation which helped to identify the primary effect of polyphosphates on the colour cycle of meat. Lipid oxidation, determined as thiobarbituricacid-reactive substances, was significantly lower in patties with added diphosphate and triphosphate than in patties with trimetaphosphate added as well as in patties without addition of condensed phosphates. For oxidation of lipids, diphosphate and tripolyphosphate each counteracts the pro-oxidative effect of added salt. The pro-oxidative effect on oxymyoglobin and the anti-oxidative effect on lipids noted for diphosphate and tripolyphosphate are discussed in relation to the coupling between oxidation of pigments and lipids during freezer storage of minced beef.