Bringing it All Together

• Ground meats have a naturally coarse texture when they're cooked. If you throw a pound or two of ground beef into a skillet or baking dish and pop it into your oven without any further preparation, the finished beef will utterly lack the smooth and even texture of a good meatloaf. That's because the added ingredients -- usually some combination of eggs, breadcrumbs and milk -- bind the loaf's meat, fats and liquid together in a smooth emulsion. Like a good pate, the whole is greater than the sum of its parts.

How Milk Helps

• As an animal product, milk is surprisingly similar to meat in many ways. Its water content is higher, but it is rich in proteins and contains a modest quantity of fat. The water in the milk adds moisture to the meat mixture, while the milk's proteins -- flowing around and between the pieces of ground meat -- set and congeal in the oven's heat, helping hold everything together. Milk is even more helpful when it's combined with breadcrumbs, which amplify its effect.

Making a Panade

• Keeping milk's moisture in the meatloaf is an important goal, contributing greatly to the quality of the finished loaf. Combining the milk with breadcrumbs makes a dramatic difference, because of the dry starches in the bread. Those starches soak up much of the water from the milk, holding it initially through simple absorption as a sponge might. When the loaf is baked, those starches in the bread expand dramatically and trap the moisture more permanently, forming a gel. This gel, like the proteins in the milk, helps bind the meat together into a smooth and even emulsion.

A Bit of Nutrition

• Aside from its role in giving the meatloaf a desirable texture, milk adds to its nutritive value. Protein is the milk's primary nutrient, but that isn't in short supply in an entree composed primarily of meat. Much of the milk's value comes through its micronutrients, most notably calcium. A cup of milk contains more than one-quarter of the recommended daily allowance of that mineral. Milk is also a notable source of several B-vitamins, and many brands include added vitamin A and D. It also adds phosphorus, selenium, potassium and numerous other minerals.