Plump hot dog. Succulent turkey. Tender pot roast. Keeping meat and poultry juicy takes effort, but it does not need to be stressful for the home cook or chef. Processors can improve the water-holding capacity (WHC) of animal protein through careful selection of raw materials – the meat and poultry – as well as the addition of ingredients that assist with improving water retention before, during and after cooking.
Meat and poultry, surprisingly, is mostly composed of naturally occurring water. It is the water content that makes cooked muscle palatable.
On average, lean meat and poultry muscle at rigor is 75 percent water, with some variation by species, muscle cut, season and pH of the meat, according to the US Dept. of Agriculture. While being a concentrated source of water, meat and poultry is typically consumed for its protein content, which is about 20 percent. The remaining 5 percent is mostly fat, with miniscule amounts of carbohydrates, vitamins and minerals.
There’s also intramuscular fat, which impacts total fat content of untrimmed and bone-in cuts, and ground and comminuted products. Fat contributes to juiciness, as well as overall flavor; however, with dietary recommendations guiding consumers to limit saturated fat intake, which is the primary fat found in meat and poultry, consumers increasingly are choosing leaner cuts.
This makes water content even more important, as moisture content of packaged meat and poultry –raw whole muscle, uncooked ground, and processed/formed products, such as deli meats, nuggets, meatballs and sausages – directly influences eating quality and texture. That makes binding and retaining inherent moisture, as well as adding moisture during processing, a critical product formulation consideration.
Most of the water in muscle is held within the structure of the muscle itself, either within the myofibrils (long protein strands) or between the myofibrils and other cell parts. Once harvested, some of the proteins often lose their grip, or water-binding ability. This is because after slaughter, the glycogen in muscle is converted into lactic acid. This causes the pH of a live animal, which is 6.8 to 7.3, to drop to 5.4 to 5.8. The pH impacts protein structure, which in turn influences its functionality. The higher the pH, the greater the protein’s ability to bind moisture.
Further, there is a correlation between the quality of the muscle in the live animal and the amount of moisture lost in prepared meat and poultry products. Food manufacturers must rely on meat and poultry processors to provide quality raw material, as WHC varies with animal genetics, pre-slaughter stress and postmortem treatments, among other variables.
Poor WHC of meat and poultry results in low cook yields due to high drip and purge loss, often along with a dry, rigid, chewy cooked product. One way to improve WHC is to increase postmortem pH up to about 6. This can be accomplished through the addition of functional ingredients, as well as environmental considerations. Even something as simple as the pH of factory water may make a difference.
High pressure pasteurization (HPP) is emerging as one way to improve WHC in raw meat and poultry. This non-thermal cold processing technology is best known for its ability to destroy spoilage and pathogenic microorganisms. Various studies show that this non-invasive process induces protein modifications that may result in product texture and water retention improvements, including higher cook yields and reduced purge.
On the ingredient side, there are various ingredients for meat and poultry manufacturers to use to bind moisture – inherent juices or added water – and lock it in the protein matrix. There are basically two categories based on functionality. There are the protein modifiers, with the most common being phosphates, and the humectants, which hold water and subsequently thicken or gel within the meat structure.
Depending on the product, the two may be used together for best results. Application varies by product form.
With bone-in or boneless whole-muscle products, for example, moisture is added in the form of a brine or marinade. This can be via immersion, injection or vacuum tumbling, or a combination. Immersion is the original approach to brining or marinating. As the name suggests, the process involves submerging the muscle into a solution, and over time, the ingredients penetrate the muscle through diffusion. Most manufacturers prefer the other two processes, as they are more reliable for even distribution of water-binding ingredients.
Injection, for example, involves the use of inserting needles deep into the muscle. The needles then inject the solution, where it has a better chance of spreading throughout. Vacuum tumbling involves massaging, which tenderizes the protein, and spinning the muscle with the brine or marinade, followed by vacuum to seal in the added solution.
Beef is the least likely to be enhanced, because of its inherently high fat content, which contributes to juiciness. Many poultry and pork formats, on the other hand, are often enhanced.
Regardless of protein source, ground and formed products, including balls, links and patties, are also commonly enhanced. The water may be added directly to emulsified and formed products by mixing it into the ground-meat matrix. These products may be sold raw or fully cooked.
Most fully cooked meats, such as heat-and-serve entrees, as well as ready-to-eat products like deli meats, hot dogs and sausages will contain added moisture. This includes hams, which have specific labeling guidelines in terms of added water.
That’s because water is an integral part of the curing process, which turns whole muscle pork into ready-to-eat ham. In the US, ham must follow protein fat-free (PFF) regulations stipulating that a product needs to contain at least 20.5 percent protein, after fat removal, to be labeled simply as ham. There are three other categories. “Ham with natural juices” must contain at least 18.5 percent protein, while “ham water added” is at least 17 percent protein. There’s also “ham and water product,” which has a PFF of less than 17 percent. These ham products must declare the percent of added nonmeat ingredients – water, binders, etc. – on labels.
Regardless of application, if water is added, it must be declared on the ingredient statement at the position it appears as a percentage of the formulation. Further, there are legal limits that vary by product, ranging from as little as 3 percent in fresh meats to more than 40 percent in highly enhanced hams. These limits exist to prevent consumer deception.
The most common protein modifiers are food-grade phosphates. These are derived from the element phosphorus, which is naturally found in many phosphate minerals. Phosphates assume many forms and are recognized as protein modifiers because of their ability to raise pH. This in turn opens up the protein structure in meat and poultry, increasing the number of binding sites for water, and thus increasing WHC.
Phosphates are able to shift pH due to their buffering capacity, with short-chain phosphates generally having the greatest impact. Phosphates also serve other functions in meat and poultry, including preserving color, assisting with freeze/thaw stability, maintaining flavor and preventing rancidity of fat along with the development of warmed-over-flavor when a product is reheated. Thus, processors often use blends of phosphates designed for specific applications. The usage level for sodium and potassium phosphates in meat and poultry products is limited to 0.5 percent.
A humectant attracts and retains moisture in a system. In meat and poultry, it absorbs and binds water. Various carbohydrates function as humectants, as do isolated protein ingredients, such as those derived from eggs, milk and soy; however, carbohydrates tend to be a more economical option. They also don’t contribute a protein allergen into the food system.
As demand for clean-label meat and poultry products increases, suppliers are offering functional native starches sourced from potatoes, rice and tapioca for an improved sensory experience without compromising on taste and appearance. Such ingredients address consumers’ desire for foods made with simple, recognizable ingredients.
So do a growing number of natural whole food ingredients that provide humectancy. One such ingredient is honey, which can be added to marinades, as well as blended into meat systems. It is being used by many in the meat snack category, including Organic Valley/CROPP Cooperative, La Farge, Wisconsin. The company uses organic honey to enhance the quality and shelf life of its shelf-stable meat and chicken bars. Honey gives the bar a nice bite and mouthfeel. Without it, the bars would be dry and hard to chew.
There are important considerations when working with honey in product development. This is because honey can be as much as 1.5 times sweeter than sugar, on a dry basis. Honey also contains enzymes that can break down other ingredients in a formulation, impacting the finished product. Honey varies in color, flavor and even consistency, based on the flower from which worker bees extract nectar that eventually becomes honey. The colors of honey form a continuous range from water white to dark amber. Light-colored honey typically has a mild flavor, while a darker color is more intense. This can be used to provide signature color and flavor to meat and poultry products.
Plum ingredients are another natural humectant. There are a number of options depending on the application. For example, fresh plum concentrate is made from the juice of fresh prune plums and can be used in marinades. The concentrate is high in plum fiber, which is made from dehydrated prune pulp. This hygroscopic fiber can absorb about six times its weight, which not only helps meat products retain moisture but also allows seasoning rubs to stay on the surface of the meat, instead of letting the salt in the rub draw out moisture and dislodge seasonings. It is readily mixed into ground-meat products or dissolved in marinades.
Fiber food ingredients sourced from plants have long been used in meat and poultry products to provide varied functions, including water holding, gel forming and fat binding. The most common applications include luncheon meats, meatballs, patties and sausages.
One such option is chicory root fiber, also known as inulin. It has been shown to functionally replace phosphates to improve moisture retention, particularly in raw poultry products. Chicory root fiber contains a minimum of 85 percent dietary fiber and has the ability to bind water in processed meats, improving the product’s sensory characteristics and boosting yields through cook cycles. It may also be used as a fat replacer in low-fat meat applications. It can be added up to 5 percent of the product formulation.
Another option is citrus fiber, which can be used along with clean-label starches, such as native rice starch, to maintain yields when replacing chemical phosphates. Some citrus fiber ingredients are as much as 70 percent dietary fiber (soluble and insoluble) and contain nearly 10 percent protein content. When used at less than 1 percent of the formulation, citrus fiber has been shown to reduce purge by up to 4 percent and increase yields by 4 to 5 percent.