Formulation, smoking are keys to improved sausage peelability
The function of a cellulose casing is to permit the processing of a sausage in a desired shape. Once the processing has been completed and the sausage is in its final form, the casing can be discarded.
The casing has to be peeled off the product. In order to accomplish this, a casing must have permeability to smoke and vapor moisture; a certain elasticity and enough strength to maintain its shape and to withstand the mechanical stress of today's high-speed stuffing equipment.
Depending on the size and weight of the individual sausages, between 300 and 500 sausages are stuffed and linked a minute.
The basic requirement for the production of a frankfurter-type sausage is the formation of a protein skin on the sausage surface to give the product firmness and "body," and to permit the peeling of the casing after it has served its purpose. The better the protein skin, the easier the sausages can be peeled.
Furthermore, the casings have to be treated during the processing in such a way that they are in the best possible condition at peeling.
Formulation
Formulation of the meat emulsion is an essential factor in the formation of a good skin. The myosin part of the lean meat is the deciding factor for the emulsification of the meat/fat/water mixture.
When establishing a frankfurter formula, this fact should be considered. A high collagen content of the emulsion reduces peelability considerably. The same is true for excessive additions of binders, flours and starches.
Remember that only the protein present in the meat emulsion in the first place can be coagulated.
In other words, the formation of a good protein skin in sausages depends directly on the quality of the raw materials used. Fat and added moisture portion play equally important parts, and all ingredients have to be in proper balance for optimum results under given circumstances.
Emulsification plays an important role, since if done properly, all the available protein is activated and the fat properly emulsified in order to form a stable emulsion.
Since protein is soluble in a saline solution, it is good practice to first chop the lean meat using salt and water or ice, then add the fat. In this connection, the high salt procedure for chopping emulsions should be mentioned.
A close temperature control is most important for best results. Whereas the best protein extraction is obtained at temperatures slightly above the freezing point, a certain temperature raise is necessary for the proper emulsification of lean, fat and water.
Optimum weights have been obtained in the 55 degrees F to 56 degrees F range, at which point the emulsion is ready for stuffing.
Casings should always be stuffed to the recommended diameter. Overstuffing and understuffing will usually result in poor peelability.
Smoking
Smoking is perhaps the most important part in the entire processing cycle responsible for peelability quality. The degree of adhesion between casing and meat surface is determined mainly by the manner in which the product is smoked.
Excessive temperature and insufficient relative humidity are usually the main reasons for peeling problems.
Since temperature-humidity controlled smoke houses with forced air circulation have come into use, the processing of skinless sausages has been greatly facilitated. These installations, when properly used, ensure optimum peeling performance and help to maintain a uniform processing shrink.
Basic requirements for these types of installations are a controlled source of dry heat and a controlled source of relative humidity. For both, exact and accurate instruments are necessary.
As soon as the product is fully cooked, it should be cooled immediately, at least to an internal temperature of 100 degrees F.
The sausages are then left at room temperature for a short period of time in order to avoid light spots on the product. All sausages must be uniformly cooled.
If product is not cooled immediately or sufficiently, the internal heat of the sausages will evaporate the moisture in the casing and the casings will be excessively dry.
If product is placed in holding coolers, the installation of humidifiers, reducing fan speed, avoidance of all drafts and covering the sausage trucks with plastic sheets should be considered. It will keep product from drying out, which assures good peeling.
The preceding is an edited version of a skinless sausage report written by the Hans Schneider of Teepak Inc. The report was used in an Iowa State University short course on sausage and processed meats.