By Eben van Tonder, 20 May 2026
Abstract
This article presents a working protocol for producing formed spaghetti style mince from old nomadic Zebu cattle for modified atmosphere packaging. Conventional partial freezing of primal cuts, followed by mincing through a forming plate, fails to produce cohesive strands because the lean Zebu raw material lacks the intramuscular fat and the surface protein mobility that young taurine beef provides. The protocol described here addresses the failure through seven reinforcing layers: a salt and phosphate brine, mechanical protein extraction by paddle mixing, a chicken skin emulsion (Hühnerhautstoss) for fat plasticisation, a beef tendon collagen gel (HeatCut Sehnenstoss) for structural filler, microbial transglutaminase for covalent stabilisation, partial freezing for clean extrusion, and a tray hold for enzymatic completion. A five treatment trial protocol is given for confirming the contribution of each layer before scale up.
The Problem
A commercial mincer fitted with a forming plate produces spaghetti style strands from beef. The format requires the extruded strands to hold their geometry in the tray for the full shelf life of the chilled product. For young taurine beef this is achieved by partial freezing of the primal to between minus 2 and minus 4 °C, followed by mincing through the plate. The cohesion comes from two sources at the strand surface. The first is intramuscular fat, which softens at the friction temperature of the mincer and acts as a plasticising film between strands. The second is myofibrillar protein released at the cut surface, which provides a sticky adhesive layer where strands touch each other.
When the raw material is old nomadic Zebu, both sources fail. There is almost no intramuscular fat. The myofibrillar protein released at the cut surface during mincing is insufficient on its own to bind the strands. Therefore the strands collapse in the tray and the product resembles ordinary mince rather than the intended spaghetti format. This outcome is observed even when the cut is topside, silverside, or thick flank, and even when the meat is taken to minus 18 °C before mincing. The failure is a compositional problem, not a temperature problem.
Standard industry context
European and South African processors producing fresh spaghetti style mince work with young Bos taurus or taurus indicus crossbred cattle. They do not tumble the meat and they do not add transglutaminase, because the raw material itself contains enough fat and enough easily extracted surface protein to produce cohesive strands at the mincer plate. Tumbling and transglutaminase are standard practice in restructured steaks, formed roasts, and bonded bacon products, however they are not used for fresh mince in mainstream European or South African production. The protocol set out in this article is therefore a transfer of established restructured meat practice into the fresh strand format, made necessary by the specific limitations of old nomadic Zebu raw material.
Why Old Zebu Meat Behaves This Way
Intramuscular fat
Old nomadic Zebu cattle carry minimal intramuscular fat. The animals are worked through long lifetimes on rangeland diets and they do not deposit marbling in significant quantity. Therefore the plasticising film of softened fat that binds strands in young taurine beef is absent. This is the dominant reason for the failure of the spaghetti format in this raw material.
Water binding and protein extractability
Mature Bos indicus muscle tends to sit closer to its isoelectric point than young taurine beef. At the natural pH of the meat there is less free water and less mobile protein at the cut surface during mincing. Less surface protein means less adhesive material between strands. The phosphate component of the brine addresses this by raising the pH above the isoelectric point and increasing both water binding and protein mobility.
Connective tissue characteristics
The collagen network in mature Bos indicus cattle is heavily crosslinked through pyridinoline and other mature crosslinks. This is documented in the work of Bailey and Light and confirmed for tropical cattle in publications from Embrapa Pecuária Sudeste in Brazil. Mature crosslinks affect cooked meat toughness strongly. Their effect on fresh strand cohesion is smaller, because the thicker external sheaths are removed during trimming and the internal perimysium contributes less to fresh strand cohesion than the surface protein and fat film do. The mature crosslink chemistry is however relevant to the Sehnenstoss component of this protocol, because the tendon material must be pre processed to overcome these crosslinks before it can function as a collagen filler.
What Must Be Engineered
Two functions must be added to the raw material to produce the spaghetti format. The first is an immediate adhesive and plasticising system at every internal surface that will become a strand surface during mincing. This provides cohesion at the moment of extrusion and holds the strands in the tray at zero hours. The second is a covalent stabilisation of the bonded structure during the tray hold, which prevents slump over the chilled shelf life of the product.
The protocol delivers these two functions through seven reinforcing layers, summarised in the table below. Each layer addresses a specific failure mode of the Zebu raw material. The layers are additive, with some reinforcement between them, particularly between fat plasticisation (layer 3) and protein adhesion (layer 2) at the moment of extrusion.
The Seven Layers of the Protocol
| Layer | Mechanism | Function in the Strand |
| 1 | Salt and phosphate brine | Solubilises myofibrillar protein at every cube surface. Raises pH above the isoelectric point. Increases water binding and protein mobility. Particularly important for mature Bos indicus meat, which sits closer to its isoelectric point than young taurine beef. |
| 2 | Mechanical extraction (paddle mixing or tumbling) | Drives the solubilised protein to the cube surfaces as a sticky exudate. Distributes brine evenly through the meat. The visible end point is a tacky white film on every cube. |
| 3 | Chicken skin emulsion (Hühnerhautstoss) | Delivers a plasticising fat phase distributed through every cube interface. Replaces the intramuscular fat that lean Zebu cattle lack. The collagen content of chicken skin adds tackiness and self stabilising emulsion behaviour. Religiously acceptable across West African markets. |
| 4 | HeatCut Sehnenstoss | Beef tendon collagen gel from the same Zebu animals, processed under the validated HeatCut method. Provides a hydrated collagen matrix that fills space, binds water, and contributes textural body. The collagen has been pre processed to address the mature crosslink chemistry of the raw tendon. |
| 5 | Microbial transglutaminase | Catalyses isopeptide bonds between glutamine and lysine residues. Crosslinks the extracted myofibrillar protein, the chicken skin proteins, and the Sehnenstoss collagen at the strand interfaces during the tray hold. Converts initial adhesive bonds into covalent bonds. |
| 6 | Partial freezing before mincing | Brings the composite cubed material to between minus 2 and minus 3 °C. Provides the mechanical rigidity needed for clean extrusion through the forming plate. Preserves the protein film and emulsion integrity through the mincer. |
| 7 | Tray hold at 2 to 4 °C | Provides time for the transglutaminase to crosslink all protein interfaces. Substantial crosslinking develops within 1 to 2 hours. Essentially complete reaction within 4 to 6 hours. A 24 hour hold gives full structural stabilisation. |
Brine Composition
The brine carries the salt, phosphate, and water. Microbial transglutaminase is not added to the brine. It is applied as a dry surface dust at a later step, because it is partly inhibited at the high local ionic strength at the point of brine contact and because it would begin acting too early in the process if dissolved in the brine.
| Component | Percentage on finished weight | Function |
| Sodium chloride | 2.2 to 2.5 percent | Solubilises myofibrillar protein. Provides ionic strength for protein extraction. |
| Diphosphate or tripolyphosphate blend | 0.4 to 0.5 percent | Raises pH above isoelectric point. Improves water binding. |
| Water | 6 to 8 percent of green weight | Carrier for salt and phosphate. Reduced from 10 to 12 percent to compensate for water carried in the Hühnerhautstoss and Sehnenstoss. |
| Microbial transglutaminase (applied separately as dry dust) | 0.5 to 1.0 percent on meat weight | Catalyses isopeptide bonds. Crosslinks the protein film during tray hold. |
The water level in the brine has been reduced from 10 to 12 percent (typical for tumbled meat without other water sources) to 6 to 8 percent to compensate for the water contributed by the Hühnerhautstoss (which is approximately 30 percent water) and the Sehnenstoss (which is a hydrated collagen gel). Without this reduction, the composite system would carry more water than the protein matrix can bind and free water would purge to the tray bottom during storage.
Hühnerhautstoss Preparation and Specification
Chicken skin emulsion is a documented Brühwurst ingredient in the German and Austrian poultry processing literature, used principally in poultry frankfurters and lyoners but also as a fat protein component in mixed species products. Chicken skin contains approximately 40 to 50 percent fat, 15 to 20 percent protein (predominantly collagen with smaller amounts of adherent myofibrillar protein), and 30 to 40 percent water. The fat is predominantly unsaturated, which makes the skin softer at chilled temperatures than pork backfat or beef tallow. This softness is advantageous for fresh strand cohesion because the plasticising film at the mincer plate develops more readily from a softer fat phase.
The collagen content of chicken skin gives it a second functional role beyond fat delivery. When chicken skin is bowl chopped with salt, the collagen partially hydrates and the skin produces a stable self emulsifying paste rather than separating into fat and protein phases. The technical name in German practice is Hühnerhautstoss or Geflügelhautstoss.
For West African production, chicken skin has three additional advantages. It is religiously acceptable across the market (no pork issue, halal compatible if the chickens are slaughtered appropriately). It is locally available from poultry processing operations. It is significantly cheaper than beef fat trim of equivalent quality.
Hühnerhautstoss composition
| Component | Percentage on total emulsion weight | Notes |
| Fresh chicken skin with adherent subcutaneous fat | 60 to 65 percent | Collected from the processing line within 4 hours of slaughter. Chilled to 0 to 4 °C immediately. Pre minced through 8 to 13 mm plate. |
| Water as ice | 25 to 30 percent | Added as ice to control temperature during bowl chopping. Critical for preventing fat separation. |
| Sodium chloride | 2.0 to 2.5 percent | Solubilises skin proteins. Stabilises the emulsion. |
| Diphosphate or tripolyphosphate blend | 0.3 to 0.5 percent | Optional. Improves protein extraction from the skin. |
Hühnerhautstoss preparation procedure
| Step | Stage | Action and Parameters |
| 1 | Skin collection | Collect fresh chicken skin within 4 hours of slaughter. Chill immediately to 0 to 4 °C. Do not use aged skin. Microbial baseline must be controlled at this point. |
| 2 | Pre mincing | Pass the chilled skin through an 8 to 13 mm plate to break it down into a workable particle size for the bowl chopper. |
| 3 | Bowl chopping | Load the bowl chopper with the pre minced skin, salt, and optional phosphate. Begin chopping at slow speed. Add ice gradually over the first 1 to 2 minutes. Increase to high speed. Chop to a smooth tacky paste. Total chopping time 4 to 6 minutes. Temperature must not exceed 12 °C, because higher temperatures cause fat separation. |
| 4 | Packaging and storage | Portion the finished emulsion into use sized blocks (typically 2 to 5 kg). Vacuum pack. Freeze immediately to minus 18 °C or below for storage. Treat as a high risk ingredient. |
| 5 | Tempering before use | Temper frozen blocks to approximately minus 2 °C before use. Tempered blocks can be added directly to the paddle mixer in measured pieces. |
Critical control for Hühnerhautstoss
Chicken skin carries a higher baseline microbial load than red meat, particularly for Salmonella, Campylobacter, and Pseudomonas. The preparation must use fresh skin (not aged), kept cold throughout, and the finished emulsion must be treated as a high risk ingredient. Freezing immediately after preparation extends the usable life. For West African operations where abattoir level controls on poultry skin may not be at the same standard as red meat, a microbial validation under local conditions is essential before committing to production scale. This is the single biggest hygiene risk in the protocol.
HeatCut Sehnenstoss Integration
The HeatCut Sehnenstoss is the beef tendon collagen gel prepared from the same Zebu animals under the validated HeatCut method. The preparation of the Sehnenstoss itself is documented in separate technical literature and is not repeated here. The integration into the spaghetti protocol is given below.
| Parameter | Specification |
| Source material | Beef tendon trimmed from the same Zebu animals. Achilles tendon and shoulder tendon are the typical sources. Trimmed of adherent muscle and fascia. |
| Processing method | Per the validated HeatCut Sehnenstoss method. The mature pyridinoline crosslinks of the raw tendon are addressed in the HeatCut process before the gel enters the spaghetti formulation. |
| Form delivered to the paddle mixer | Frozen block tempered to approximately minus 2 °C. Cut or broken into pieces of similar size to the lean cubes (15 to 20 mm). |
| Inclusion rate | 5 to 10 percent on total batch weight. Trial work confirms the optimum for the specific Sehnenstoss batch in use. |
| Loading point | Added at the start of paddle mixing together with the lean Zebu cubes and the Hühnerhautstoss. |
The Sehnenstoss contributes a hydrated collagen matrix that fills space, binds water, and adds textural body that lean Zebu muscle lacks. The mature pyridinoline crosslinks of the raw tendon, which would otherwise prevent the collagen from functioning as a filler, are addressed during the HeatCut Stoss processing. Therefore the Sehnenstoss enters the spaghetti formulation as a pre processed ingredient with predictable properties, not as raw tendon material.
The Sehnenstoss also provides additional protein substrate for the transglutaminase to act upon. Microbial transglutaminase crosslinks collagen as well as myosin, therefore the enzyme distributes its activity across the lean muscle interfaces, the chicken skin emulsion interfaces, and the Sehnenstoss interfaces simultaneously. This spreads the bonding work across more sites and produces a tighter, more uniformly bonded composite than the enzyme would produce on lean muscle alone.
Full Production Procedure
The full procedure integrates the prepared Hühnerhautstoss and Sehnenstoss with the cubed lean Zebu meat in a single paddle mixer batch, followed by transglutaminase application, chilling, mincing, and tray hold. Vacuum tumbler operations can substitute step 6 with 45 to 60 minutes of continuous vacuum tumbling at low speed in place of the interval mixing.
| Step | Stage | Action and Parameters |
| 1 | Prepare Hühnerhautstoss | Day before, or use frozen stock. Temper to approximately minus 2 °C before use. |
| 2 | Prepare Sehnenstoss | Use frozen stock from the validated HeatCut process. Temper to approximately minus 2 °C. Break into pieces of 15 to 20 mm. |
| 3 | Cube lean meat | Cube topside, silverside, or thick flank to 15 to 20 mm. Pre chill to 0 to 2 °C. |
| 4 | Prepare brine | Chill water to 1 to 2 °C. Dissolve phosphate first, then salt. Total brine 6 to 8 percent of green meat weight. Salt 2.2 to 2.5 percent on finished weight. Phosphate 0.4 to 0.5 percent on finished weight. |
| 5 | Load paddle mixer | Load to no more than 50 to 60 percent of nameplate capacity. Add lean cubes (75 to 80 percent of batch), Hühnerhautstoss (10 to 15 percent), Sehnenstoss (5 to 10 percent) together. |
| 6 | Interval mixing | Slowest speed. Add brine over the first 2 to 3 minutes. Mix 15 minutes, stop, probe temperature (below 4 °C). Mix another 15 minutes, stop, probe again. A third interval may be added. Total 30 to 40 minutes. End point: tacky white exudate on every surface. |
| 7 | Add transglutaminase | Dust dry microbial transglutaminase at 0.5 to 1.0 percent on meat weight evenly. Mix on slow speed for 3 to 5 minutes only. |
| 8 | Chill | Chill the composite to between minus 2 and minus 3 °C. Spread in shallow trays in a freezer with a probe in the meat. Remove at target temperature. |
| 9 | Mince | Mince through the forming plate directly into the MAP tray. |
| 10 | Tray hold | Hold at 2 to 4 °C for a minimum of 4 to 6 hours, preferably 24 hours, before sealing under MAP. |
Critical Control Points
Temperature throughout
Temperature control is the single largest process risk. If the meat warms above 6 °C during paddle mixing, protein extraction becomes excessive and sticky rather than functionally cohesive, the chicken skin fat begins to soften and separate, the Sehnenstoss collagen partially dissolves, bacterial growth accelerates on the combined system, and the transglutaminase added at step 7 will act on partly denatured protein. A probe thermometer must remain in the meat throughout mixing and mixing must stop if the temperature climbs.
Hygiene baseline
The composite system combines three biological substrates (lean Zebu muscle, chicken skin emulsion, beef tendon collagen gel), each with its own microbial profile. The chicken skin component is the highest risk. A validated hygiene baseline at each ingredient preparation step is essential. The finished product shelf life under MAP is bounded by the worst hygiene component, not the average.
Water balance
The brine water has been reduced to 6 to 8 percent of green meat weight to compensate for the water carried in the Hühnerhautstoss and Sehnenstoss. If trial work shows water purge at the tray bottom by 24 hours, reduce the brine water further. If trial work shows the meat is too dry and the strands are crumbly, increase the brine water. Adjust by 1 to 2 percentage points per iteration.
Tray hold time
The minimum tray hold at 2 to 4 °C is 4 hours. Less than this gives incomplete transglutaminase crosslinking and the strands will slump during shelf life. The preferred hold is 24 hours where production scheduling permits, because this gives essentially complete enzymatic reaction and the most stable final structure.
Five Treatment Trial Design Before Scale Up
Before scaling up, a five treatment trial confirms the contribution of each layer on the specific raw material in use. The trial uses topside material from the same animal across all five treatments. All five are minced at minus 2 °C and trayed identically. The trays are photographed at 0, 4, 24, and 72 hours, held at 2 to 4 °C throughout.
| Treatment | Composition and Process | What It Tests |
| 1 | Untreated Zebu mince. Topside through forming plate at minus 2 °C with no pre treatment. | Baseline failure of the raw material. Strands expected to collapse at zero hours. |
| 2 | Cubed, brined, paddle mixed Zebu only. No fat, no Sehnenstoss, no transglutaminase. | Whether protein extraction alone is sufficient. If treatment 2 holds at zero hours, the protein extraction layer is doing real work. |
| 3 | As treatment 2 plus 10 to 15 percent Hühnerhautstoss. | The contribution of fat plasticisation and chicken skin collagen. Likely the largest single gain over treatment 2 because fat addresses the dominant cause of failure. |
| 4 | As treatment 3 plus 5 to 10 percent Sehnenstoss. | The contribution of the beef collagen filler. Expected to improve strand body and reduce water purge. |
| 5 | As treatment 4 plus transglutaminase. The full protocol. | Stabilisation over shelf life. Expected to maintain strand definition through 24 hours and beyond. |
Interpreting the trial results
Treatment 1 establishes the baseline failure and confirms that the raw material genuinely requires intervention. Treatment 2 establishes whether protein extraction alone produces strand cohesion. Treatment 3 establishes the contribution of fat plasticisation, which is expected to be the largest single gain. Treatment 4 establishes the contribution of the collagen filler. Treatment 5 confirms the full protocol with enzymatic stabilisation.
If treatment 3 already holds well through 24 hours, the Sehnenstoss and transglutaminase may be optional rather than essential for the format and the protocol can be simplified. If treatment 5 fails, the problem is not the additives and process control (temperature, mixing time, mincer condition, raw material variability) must be examined. The trial separates ingredient contributions from process contributions, which is essential for optimisation.
Likelihood Assessment
The protocol stacks seven established mechanisms to address the specific deficiencies of old nomadic Zebu raw material. None of the individual layers are experimental. The novelty is the combination applied to this specific raw material in this specific product format. The structured likelihood estimate is given in the table below.
| Outcome | Likelihood | Basis |
| Cohesive strand formation at the mincer plate (zero hours) | 80 to 85 percent | Fat plasticisation plus protein extraction together replicate the natural cohesion mechanism of young taurine beef. |
| Strand geometry maintained through 4 hours of tray hold | 85 to 90 percent | Conditional on cohesion at zero hours. Transglutaminase begins acting immediately and substantial crosslinking develops within 1 to 2 hours. |
| Strand geometry maintained through 24 hours of tray hold | 75 to 80 percent | Transglutaminase reaction essentially complete. Risks: oxidation of chicken skin fat, water purge, MAP discolouration. |
| Acceptable retail product through 5 to 7 days under MAP | 60 to 70 percent | Unknown territory. Closest analogue is restructured beef with TG under MAP from Kulmbach work. |
| Overall first trial success producing saleable product | 60 to 70 percent | Rising to 80 percent with one or two iterations adjusting transglutaminase dose, chicken skin percentage, and Sehnenstoss percentage. |
Principal failure modes to anticipate
Three failure modes are worth flagging. The first is hygiene driven spoilage from the chicken skin emulsion if the source material is not adequately controlled. The second is water purge from over hydration of the composite system if the brine water is not reduced to compensate for the Hühnerhautstoss and Sehnenstoss water content. The third is visible streaking in the strands if the Hühnerhautstoss and Sehnenstoss rheology differ significantly from the lean cubes during extrusion. The first is the most serious and must be controlled at the chicken skin preparation step. The second and third are cosmetic and can be optimised through iteration.
Relationship to Established Restructured Meat Practice
The protocol is conceptually identical to the restructured beef approach documented for cull dairy cow meat in the publications of the Max Rubner Institut at Kulmbach during the late 1990s and 2000s, and to the commercial restructured beef systems marketed by Ajinomoto under the Activa designation. The Hühnerhautstoss preparation follows established German and Austrian poultry comminuted product practice. The Sehnenstoss component derives from the validated HeatCut method for tendon and skin processing developed for Zebu raw materials specifically. The transglutaminase use follows the Kuraishi and Ajinomoto technical guidance and is reinforced by the Kulmbach work on cold set binding systems.
The novelty for the Zebu application is the integration of all these established practices into a single composite protocol for a fresh strand product format. The format is not standard industry practice in Europe or South Africa for taurine cattle, because taurine cattle do not require it. The protocol therefore represents a new application of established meat science rather than new meat science as such.
Summary of Key Points
- Old nomadic Zebu meat fails to produce cohesive spaghetti strands because of minimal intramuscular fat and reduced surface protein mobility. Cold treatment alone does not solve the problem.
- The protocol stacks seven reinforcing layers: brine, mechanical extraction, Hühnerhautstoss, Sehnenstoss, transglutaminase, partial freezing, and tray hold.
- Hühnerhautstoss (chicken skin emulsion) is the key fat plasticisation component. It is religiously acceptable, locally available, and cost effective for West African production. It is also the largest hygiene risk in the protocol and requires fresh skin and tight microbial control.
- HeatCut Sehnenstoss provides a hydrated collagen filler from the same Zebu animals. It addresses the structural body that lean Zebu lacks and contributes additional protein substrate for the transglutaminase.
- Brine water is reduced to 6 to 8 percent of green weight (from the typical 10 to 12 percent) to compensate for water carried in the Hühnerhautstoss and Sehnenstoss.
- Microbial transglutaminase is the stabiliser of bonds already formed by extracted protein. It is applied as a dry dust after mixing, not in the brine. It crosslinks myosin, chicken skin protein, and collagen simultaneously.
- Temperature control is the single largest process risk. Mixing must stop if the meat warms above 6 °C.
- Likelihood of successful strand formation at the mincer plate is 80 to 85 percent. Likelihood of acceptable retail product through 5 to 7 days under MAP is 60 to 70 percent on first trial, rising to 80 percent or better with one or two iterations.
- A five treatment trial must be run before scale up to confirm the contribution of each layer and to set the working transglutaminase dose.
References
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