Denaturing Myoglobin with Acetic Acid and Neutralizing with Sodium Bicarbonate

29 May 24
Eben van Tonder

To ensure complete precipitation of myoglobin proteins from the solution for use in sausages, follow this detailed procedure:

Materials:

  • Myoglobin solution
  • Concentrated acetic acid
  • Sodium bicarbonate solution
  • pH meter
  • Stirring equipment
  • Filtration or centrifugation setup

Procedure:

1. Temperature Control:

Maintain the solution at a temperature of 4°C (refrigerated conditions) throughout the process. This helps to stabilize the proteins and enhance precipitation.

2. Denaturation:

    -> Slowly add concentrated acetic acid to the myoglobin solution while continuously stirring.

    -> Monitor the pH closely and stop the addition when the pH reaches 1. This will denature the proteins, causing them to unfold and begin precipitating out of the solution.

    3. Incubation:

    After reaching pH 1, let the solution sit at 4°C for 30 minutes to ensure complete denaturation and initial precipitation.

    4. Neutralization:

    -> Gradually add sodium bicarbonate solution to the acidic myoglobin solution while stirring.

      -> Add the sodium bicarbonate slowly to avoid rapid pH changes, which can cause protein re-solubilization.

      -> Monitor the pH closely and continue adding sodium bicarbonate until the pH reaches 7. This neutralization ensures that the proteins remain precipitated.

      5. Precipitation and Recovery:

      ->Allow the solution to sit at 4°C for an additional 30 minutes to ensure complete precipitation of the proteins.

      -> Use filtration or centrifugation to separate the solid protein precipitate from the liquid. For centrifugation, use a speed of approximately 10,000 g for 10-15 minutes.

      6. Washing:

      -> Wash the recovered protein precipitate with cold distilled water (4°C) to remove any residual acetic acid and sodium bicarbonate.

      -> Repeat the centrifugation or filtration to collect the washed protein precipitate.

      Summary:

      By following these steps, you can effectively denature and precipitate myoglobin proteins for use in sausage production. Maintaining a low temperature (4°C) throughout the process is crucial for optimal protein stability and precipitation..