Meat emulsions - batters

1. Meat emulsions - batters • Frankfurters are the best example -produced with unique technology that is highly protein dependent -failures, i.e. “broken” emulsions are a dramatic mess (fat caps where separated fat rises to upper ends of the frankfurters as they hang on smoketrucks during cooking, then solidifies into solid fat when chilled) -successful, i.e. stable emulsion/batter is the result of 3 factors:

2. Emulsion/batter stability is determined by: 1. Meat quality • meaning - myofibrillar protein content and functionality • quality problems like PSE pork can result in emulsion/batter problems • WHC and fat binding 2. Handling knowledge and technology • meaning - appropriate use of salt, temperature, added water and chopping to properly manage soluble protein and dispersed fat 3. Additional binders to help stabilize emulsion/batters and control physical properties

3. Before we cover specifics --- some definitions emulsion - stable dispersion of one immiscible liquid in another • i.e. water-in-oil (mayonnaise, butter) oil-in-water - frankfurters • 30% fat is well-hidden true emulsion • dispersed particle size is 0.1µ or less meat emulsion - particle size is typically 1.0 µ or more therefore often called a “batter”

4. What is “fat binding”? 1. Fat cell walls • intact cells retain fat • dried cells i.e. “salted” can be very stable due to collagen/cell wall rigidity and impermeability 2. Emulsification membranes • myofibrillar proteins • hydrophobic portion  fat • hydrophilic portion  water

5. protein fat water Proteins rearrange somewhat and consequentlylose some water binding ability (know this) fat

7. Therefore there are three necessary components for every emulsion/batter • internal phase i.e. fat • externalphase i.e. water • emulsifier i.e. protein

9. “Membranes” are critical to raw emulsion/batters -- but cooking then results in: 3. Heat-set gelation - crosslinking proteins to form a 3 dimensional matrix • semi-rigid “trap” for fat and water • critical to cooked stability, texture, slicing, appearance

11. More definitions • Emulsion/batter capacity • maximum amount of fat or oil stabilized by a given amount of protein • measured by oil-in-water dispersion with clear blender jar, colored oil, protein solution • model system comparisons • emulsion/batter stability • amount of fat or oil retained (or separated) after stressing, usually with heat, a formed emulsion/batter • practical comparisons • affected by process technology and non-meat ingredients

12. Factors affecting stability can be found in Stokes Law: D = diameter of fat globules de = density of external phase di = density of internal phase k = constant vis = viscosity V = D2(de-di) k vis

13. Practically: V = D2 vis • smaller fat globules are more stable (also require more protein) • greater viscosity (protein solubility, protein quality, temperature, non-meat ingredients, salt concentration) is more stable

14. Processing parameters 1. Start with lean meat plus salt • best at 4-5% (brine strength) plus ice/cold water • temperature control • increased protein solubility and swelling • can chop or mix (extract) longer • low temperature increases viscosity

15. 2. Chopping/mixing • two effects a. dissolves (1-5%) and swells (remainder) of myofibrillar protein b. breaks fat cells and subdivides fat into small globules • chopping needs to be extensive enough to achieve small fat globules with solubilized protein membrane coatings • over chopping will destroy the protein membranes and “break” the emulsion/batter • usually chop lean, salt, water to about 40oF

16. Critical considerations: • chopper speed • sharp knives • bowl/knife clearance • temperature control and monitoring • add fat meat at 40oF and chop to 55oF (pork fat), 65oF (beef fat)

20. 3. pH is critical • Protein “functionality” is closely related to the pH - WHC curve / relationship • therefore increasing pH increases emulsion stability • pre-rigor meat is 50% - 100% more effective than post-rigor • phosphates are important • pre-blends (lean meat + salt + 1/2 nitrite) are very effective (and advantageous for cured color as well)

23. 4. Collagen • High collagen meat sources are a potential problem • high capacity, low stability • forms membranes but converts to gelatin when heated • however, ground/powdered collagen appears to be effective probably depending on adequate dispersion followed by gelatin formation

24. 5. Other emulsifier proteins • myofibrillar proteins might be best “saved” for WHC and gelation • “pre-emulsions” --- use another protein to coat fat globules --- then add “pre-emulsion” as fat to meat mixture • soy and caseinate • skin / collagen is sometimes used

25. 6. Vacuum processing • Chopping/mixing under vacuum can increase capacity and stability

28. 6. Vacuum processing • microscopic observations show air “bubbles” probably surrounded by protein thus consuming some protein functionality • air competes with fat for the emulsifier making the emulsion/batter less stable • more critical for round globular sarcoplasmic proteins than for filamentous, long myofibrillar proteins

29. 6. Vacuum processing • product density and diameter will differ with vacuum • can contribute “plumpness” • major effects on cured color development • with about 50 ppm in going nitrite vacuum will give good cooked color while non-vacuum will give gray cooked color • absence of air also will decrease likelihood of rancidity development • not as much an issue in cured meats as for fresh products (i.e. pork sausage)

30. 7. Stuffing • Pressure flow of product, proper casing diameter • minimize smear/separation of fat and breaking emulsion membranes prior to heating

31. 8. Heating / cooking • humidity • important to yields, thus is kept high --- only risk is high collagen content • heating rate • critical to proper protein gelation • protein unfolding  crosslinking gel formation

32. Remember: • “Bind” values listed for calculating formulations with different meat ingredients reflect waterandfat binding ability Ex. Bull meat 17.0 Pork picnics 16.0 50 pork trim 4.1 Liver 1.25 Beef hearts 0.3