Colour of ground beef as influenced by raw materials, addition of sodium chloride and low oxygen packaging

Abstract

The study aimed at examining the effects of freezing of raw materials, holding time for fresh raw materials post mortem and addition of 0.5–1.0% NaCl on the colour of ground beef under low oxygen (O 2) modified atmosphere storage. The samples were exposed to 0.1–3.0% O 2 at 4 °C for up to 10 days, and analysed for O 2 concentrations, instrumental and visual colour. Residual O 2 in the headspace of the packages oxidizes myoglobin and discolours the meat. Meat may have the ability to scavenge residual O 2, and ground beef differs from intact muscles by having a much higher capacity for O 2 consumption. In this experiment, the use of frozen/thawed raw materials and addition of NaCl both decreased the rate of O 2 consumption and increased discolouration. Using raw materials from 2 days rather than 7 days post mortem greatly increased the rate of removal of O 2 and improved redness. In low O 2 packaging, ground beef preferably should be stored for at least 2 days in an atmosphere with less than 0.1% residual O 2 to produce a purple pigment predominantly consisting of deoxymyoglobin.