Refresher on phosphates
When processors are looking to enhance the texture and improve moisture retention in their protein products, one option they can turn to is the use of approved phosphates in their formulations.
The two beneficial effects of phosphates in meat and poultry products are moisture retention and flavor protection. An example is the use of phosphates in the curing of ham where approved additives are sodium or potassium salts of tripolyphosphate, hexametaphosphate, acid pyrophosphate, or orthophosphates, declared as “phosphates” on labels.
The nomenclature applied to phosphates can be quite confusing as a particular phosphate may be described by several different names (see chart on page 48), says Lynn Knipe, processed meats extension specialist at Ohio State University.
“Phosphates are quite different from other ingredients conventionally added to meat products,” Knipe adds. “There are 11 different phosphates, which have been approved for use in meat products and each one is somewhat different from the rest in its functional properties in meat.”
Noting that the way phosphates act in meat can be explained in several ways, Knipe identifies the chemical’s water-holding capacity (WHC) of post-rigor muscle as a key benefit. The substance increases the pH of the muscle, which increases its net negative charges.
“These negative charges increase the electrostatic repulsion between fibers and ultimately increases the hydration of the muscle,” Knipe explains. “Most of the food-grade phosphates raise the pH of meat, yet the relationship between their effect on pH and WHC varies with the different phosphates.”
The result, Knipe continues, is that alkaline phosphates are very forgiving in relation to cooking loss in meat products. They will enhance the stability of emulsion products and improve the binding of meat chunks in sectioned and formed meat products. Phosphates also protect emulsion products from variations in emulsifying and cooking temperatures, and would be extremely valuable in the production of low-sodium meat products.
The emulsion stabilizing action of alkaline phosphates is due to a number of functional properties of phosphates. Alkaline phosphates raise the pH of meat products. These phosphates exhibit a high pH in water, but since meat is a buffer itself, phosphates’ effect on meat pH is considerably less than in water.
“Even the limited increase in pH (approximately 0.6 unit maximum) increases WHC and protein solubility,” Knipe says. “On the negative side, this increase on pH will reduce the rate of cured color development.”