Sodium lactate influences myoglobin redox stability in vitro.

The researchers found that sodium lactate, when injected in beef, improves the color stability of the meat. This stability is linked to an increased redox stability of myoglobin, a protein responsible for the red color in meat. However, the exact process behind this transformation remains unclear.

Study Objective and Methodology

• The primary aim of the study was to analyze the effects sodium lactate has on the redox stability of myoglobin, a process inferred to enhance the color stability in beef. This observation was made in vitro, meaning the experiments were performed outside of a living organism.
• The specific variant of myoglobin used in the study was equine myoglobin, which was subjected to different pH conditions i.e., pH 5.6 and pH 7.4 using sodium citrate and sodium phosphate solutions respectively.
• The solutions containing oxymyoglobin (the oxygen-binding form of myoglobin) were incubated at 4°C (close to normal refrigerator temperatures) and different concentrations of lactate (0, 5, 10, 100, 200mM) were introduced.
• The changes in myoglobin redox form in response to different lactate concentrations were then determined by capturing their absorbance spectra, a method which measures how much radiation a substance absorbs at each wavelength.

Findings

• The formation of metmyoglobin (the oxidized form of myoglobin which gives a brown color to meat) at both pH conditions was significantly reduced by concentrations of 100 and 200mM lactate.
• Surprisingly, the lactate concentration increase from 100mM to 200mM boosted the redox stability of oxymyoglobin, implying sodium lactate could increase the preservation of meat’s red color during storage.

Implications and Future Research

• The research suggests that sodium lactate has a pivotal role in retaining the red color in meat, potentially explaining the improved color stability seen in lactate injection-enhanced beef products.
• The mechanisms behind this enhancement are not yet fully understood, and further research is necessary to determine sodium lactate’s exact influence on beef myoglobin.