Manufacturing Tomato Ketchup (2024)

The Process

The recipe, viscosity and solids content of ketchups vary widely. Typically tomato paste is blended with water and the other ingredients and the manufacturing process continues in one of two ways:

• When utilising the pectin present in the paste as a thickening agent, fibrous strands in the tomatoes must be fibrillated (frayed) to raise capacity for water retention, which increases viscosity.
• Once mixed, the product is passed through a high-pressure hom*ogeniser to obtain the required consistency.
• This method can also be used to increase yield as a thicker product can be achieved with a lower solids content.
• With the second processing method high-pressure hom*ogenisation is not used and thickening agents such as xanthan gum, pectin or starch (including modified starches) are used to obtain the required viscosity in the finished ketchup.
• With either method mixing apparatus must be capable of dispersing powdered ingredients into water to form an agglomerate-free product.

The Solution

A Silverson high shear mixer can solve these problems and eliminate the need for additional processes such as pre-dispersion of the starches or thickeners and in some cases hom*ogenisation. Where a hom*ogeniser is used, the high shear mixing action will improve pre-mix quality and consistency. Operation is as follows:

• Stage 1

  

  Stage 1

  The vessel is charged with water and the Silverson mixer is started. The powdered ingredients are then added. The high-speed rotation of the Silverson mixer creates a powerful suction which draws the liquid and powders into the workhead. The materials are subjected to intense shear within the workhead.

• Stage 2

  

  Stage 2

  Agglomerates are broken down between the ends of the rotor blades and the stator wall. The product is forced out through the stator and returned to the mix. Fresh materials are simultaneously drawn into the workhead, maintaining the mixing cycle. The circulatory mixing pattern ensures that hydration of the thickening agents is rapidly completed.

• Stage 3

  

  Stage 3

  The tomato paste is then added and dispersed in the same manner. A hom*ogenous mixture is rapidly obtained.

The Advantages

• Dramatically reduced processing times.
• Rapid dispersion of thickeners and stabilisers.
• Improved yield of ingredients.
• Smoother texture and improved product consistency.
• Improved colour.
• Ketchup with low solids content do not require hom*ogenisation and the entire process can be completed using the Silverson mixer.
• The product fed to the hom*ogeniser is uniform and of a low particle size, allowing faster processing through the hom*ogeniser and fewer passes required.
• A Silverson mixer can be used as a “polishing step” after hom*ogenisation to improve texture, viscosity and sheen of ketchup.

The type of product, batch size and viscosity of the end product determine which mixer from the Silverson product line is most suitable: