STPP Sodium tripolyphosphate - often used as a binder by butchers, mainly to add to their sausages.

Used to increase the water binding capacity of your paste or muscle, since it slightly raises the pH of your meat, which increases its ability to hold water.

Frequently used in products which require a lot of water in your paste, such as hot dogs, bologna, or any emulsion sausage. Also works very well in brines, resulting in your smoked meats holding more water, and stay juicier longer.