Rebuilding Fat in Low-Cost Krainer-Type Sausages

By Eben van Tonder – 12 November 2025

Introduction

Fat gives sausages their characteristic juiciness, flavour release, and the gentle compression that defines a good Krainer. When fat is reduced or unavailable, the product becomes rubbery, dry, and brittle. Over the years, many processors have turned to synthetic hydrocolloids and gelling agents to compensate, but none replicate the mechanical and sensory role of fat.

In the living animal, firmness and resilience arise from a biological balance between myofibrillar proteins, collagen, and fatty tissue. The fat phase softens the network, collagen adds rigidity, and myofibrillar proteins form the continuous elastic gel that binds it all together. When re-creating this structure in a low-cost Krainer made from chicken MDM, we must therefore rebuild fat not as an ingredient, but as a phase within a designed polymer system.

Understanding Fat in the Polymer Model

According to LaBudde’s polymer theory (1995), cooked sausage is a multi-phase composite system:

  • The continuous matrix consists of salt-soluble myofibrillar proteins (mainly myosin and actin).
  • Collagen fibres act as reinforcing co-polymers, strengthening the gel and contributing to elasticity.
  • Fat droplets serve as fillers and plasticisers, softening the matrix and allowing deformation without fracture.
  • Water acts as a plasticising agent, promoting mobility and thermal reaction between the polymers.

Removing fat eliminates the lubricating phase, leaving a brittle and dense protein network. Collagen alone cannot replace fat; when heated, collagen shrinks and exudes water rather than retaining it. A functional low-cost Krainer must therefore reintroduce a dispersed phase that behaves like fat but can be made from inexpensive local materials.

Replacing Fat with Skins

Cooked and minced pork or beef skin provides a strong collagen gel that binds water and reinforces structure. However, collagen gels are elastic solids and lack the viscous, lubricating properties of fat. A sausage made purely from collagen behaves like a tightly crosslinked polymer — firm but without flexibility.

Combining skins with chicken MDM balances this system. The extracted myofibrillar proteins create the elastic continuous phase, and the collagen gel acts as a reinforcing filler. The optimal inclusion level for skin (x) in the final batter is:

  • Pork skin: 5–8 %
  • Beef skin: 4–7 %
  • Combined pork + beef: 6–9 %

At these levels, the collagen improves firmness without over-contraction or rubberiness.

Creating a Pseudo-Fat Using Sunflower Oil and Skins

To restore the missing soft, lubricating phase, a pseudo-fat can be created by emulsifying sunflower oil with collagen gel from cooked skins. This mixture disperses like real fat droplets but remains stable through the heat cycle.

Composition (100 kg batch basis):

  • Cooked, minced skin (3 mm, ≤ 4 °C): 40 %
  • Sunflower oil: 55 %
  • Salt: 2 %
  • Phosphate blend: 0.3 %
  • Ice water: 2.7 % (deduct from total recipe water)

Procedure:

  1. Load cold minced skin, salt, and phosphate into the cutter. Add half the water.
  2. Cut slowly until uniform, keeping bowl below 12 °C.
  3. Add sunflower oil in a thin stream while cutting until the emulsion turns glossy and cohesive.
  4. Add remaining water to adjust texture.
  5. Final temperature ≤ 14 °C. Chill immediately to 2–4 °C before use.

The resulting emulsion behaves like soft backfat and can be stored at 2–4 °C for up to three days.

Integration in the Krainer System

In a chicken MDM-based Krainer, the pseudo-fat emulsion replaces traditional pork backfat one-to-one. The inclusion level is typically 20 % of the total batter.

Processing sequence:

  1. Mix chicken MDM, salt, and phosphate until sticky and shiny (protein extraction).
  2. Add pre-hydrated TVP, isolate, and starch.
  3. Incorporate the cold pseudo-fat emulsion gradually while mixing gently.
  4. Maintain batter temperature ≤ 12 °C.
  5. Add remaining water and seasonings.
  6. Stuff into casings and cook to 72 °C core temperature (step programme 65 °C 1 h, 80 °C 3–4 h).
  7. Chill to ≤ 4 °C.

Performance and Cost Outcome

  • Texture: Firm and elastic with smooth bite, matching a traditional Krainer.
  • Juiciness: Maintained through the fine dispersion of sunflower oil.
  • Structure: No fat-out or jelly separation; collagen and proteins form a continuous matrix.
  • Cost: Pseudo-fat emulsion costs ≈ R23/kg compared with R45–50/kg for pork backfat, giving a finished batter cost of about R14.7/kg.

This system provides both mechanical integrity and sensory quality using accessible materials — chicken MDM, skins, and sunflower oil.

Practical Notes

  • If beef skin is used, cook 3–4 hours at 95 °C before mincing.
  • To soften texture, lower skin to 35 % and raise oil to 60 % in the pseudo-fat emulsion.
  • Keep the emulsion cold during mixing; temperature is the key to stability.
  • Always deduct the water used for skin preparation from total formulation water.

Conclusion

Fat in a sausage is more than flavour — it is a structural phase that allows the protein network to behave like living muscle. When animal fat is unavailable, its function can be rebuilt through a carefully designed skin–oil emulsion that mimics both the mechanical and sensory roles of fat.

By reconstructing the polymer architecture of muscle — collagen for strength, myofibrillar proteins for elasticity, and oil for flexibility — a low-cost Krainer made from chicken MDM can achieve the firmness and juiciness of a full-meat sausage.

This approach restores the biology of meat structure with local, affordable ingredients, guided by LaBudde’s insight that food gels are polymers, and the best systems are those that mirror nature’s own design.

References

LaBudde R. A. (1995). Review of Comminuted and Cooked Meat Product Properties from a Sol, Gel and Polymer Viewpoint.
Hong G. P., Lee S., Min S. G. (2014). Effect of pork skin gelatin on the rheological properties of meat batters and thermal stability of emulsions. Food Science and Biotechnology, 23(4), 1075–1081. https://doi.org/10.1007/s10068-014-0148-1
Choe J., Kim H. Y., Kim Y. J. et al. (2017). Effects of porcine, chicken, and bovine gelatin on quality characteristics of low-fat frankfurters. Food Science of Animal Resources, 37(3), 388–397. https://doi.org/10.5851/kosfa.2017.37.3.388