Meatloaf Under the Microscope

Consider the meatloaf. On the surface, it’s an ordinary dish, but on closer inspection, its chemistry and structure reveal mystery, complexity and even a little intrigue.

Well, maybe that’s going too far, but meatloaf does offer a good look at some of the basic processes involved in cooking, from the coagulation of the meat proteins to the moisture-retaining qualities of starches.

Why would you want to know about these things? Because it will help American cooking keep up with more ancient cuisines, like French and Japanese. Other cultures have hundreds of years of culinary experience on us, but with good old-fashioned American ingenuity and innovation, our chefs can bring American cooking to a higher level.

Remember the space race! Science and technology could enable us to bridge the miso gap! I predict that by understanding the essential science of the kitchen, we can place an American stamp on the spoon as early as 2000.

All of which brings us back to the matter at hand: a basic physical understanding of what is perhaps the most American of all meals, the meatloaf.

The typical meatloaf contains ground meat and bread crumbs, together with eggs, vegetables and seasonings (salt, pepper, catsup, etc.). Each of these ingredients in turn is composed of various combinations of proteins, carbohydrates, fat, water, vitamins and minerals, the building blocks of all foods. The interactions of these nutrients upon mixing and cooking produce a moist, meaty and massive form that makes a classic American dish.

To understand the function of the ground meat proteins, consider the meat before it is ground. Meat is composed of bundles of protein fibers, mostly the proteins myosin (thick fibers) and actin (thin fibers). These are surrounded by thin sheets of connective proteins, mostly collagen, and interspersed with concentrations of fat. Try ordering that in a restaurant.

But when the meat is ground, all these long protein fibers are broken down and the constituents are mixed together. This process frees some protein strands from the long fibers and allows them to dissolve in water released during the grinding operation. The dissolved proteins then bind with exposed proteins in the remaining chunks of meat and create an expansive protein network.

It is this web of proteins that gives meatloaf its structure. The mesh traps most of the fat and water molecules within it and allows the mixture to form a cohesive mass. That is to say, a loaf.

Beaten eggs added to the mix further reinforce the structure of the meatloaf. Egg whites are composed mainly of protein, specifically albumin, which is a globular protein. It is called globular because the long strands of protein material (amino acids) are tightly folded in upon themselves and bound together by cross-links between the molecules. When eggs are beaten, these cross-links are broken and the long strands of protein unfold. This allows the egg proteins to become entwined with all the other ingredients in the mixture, adding extra strength to the loaf and making it less prone to falling apart.

The yolks, on the other hand, contribute little to the structure of the loaf. They aid in the browning reaction on the meat’s surface and add flavor by contributing fat, calories and cholesterol. But then, maybe we should all just give eggs a break.

The other ingredients, including vegetables and seasonings, don’t contribute binding properties. Instead, they add components to the texture and flavor of the dish. Without them, meatloaf would just be hamburger, as opposed to being its more bran-rich and slightly more sophisticated big brother.

*

And the bread crumbs? Paradoxically, those dried bits of old bread actually make the loaf more moist. When the loaf--either free-form or in a pan--is baking, the protein network interwoven throughout the mixture begins to solidify (coagulate) and the web begins to tighten up. As this happens, the water that’s trapped in the protein net gets squeezed out. This is also why a well-done piece of meat is so dry.

But in a meatloaf, the moisture does not have to be lost. As the heat penetrates the food, the bread crumbs, those thirsty pieces of carbohydrate, begin to absorb all the water they can. The starch particles may swell to five times their normal size during the process, known as gelatinization. Thus, much of the water squeezed out of the meat is retained.

(If the crumbs are heated to too high a temperature, however, the starch particles will burst, and you could end up with a dry meatloaf anyway. In which case, you may want to open the Yellow Pages--also composed mainly of a carbohydrate known as cellulose--and think about making restaurant reservations.)

As for the fat trapped in the web, much of it is absorbed by the bread, but some also gets squeezed out as the proteins coagulate. The initially solid fat renders as the loaf heats up and seeps out into the pan.

This helps to make the dish lower in fat, which makes meatloaf more appealing. But to reap the full benefits of this “fat reduction,” you have to remember to pour out the fat before unmolding the loaf, something I learned less through science than through experience. (There was grease everywhere.)

Which brings up another point: Knowledge of the mechanisms and principles of food science is invaluable, but it doesn’t really take the place of common sense.

CHINESE MEATLOAF

The Chinese meatloaf is essentially the stuffing for a traditional pork dumpling writ large. Eggs are thrown in for binding, and hoisin sauce is used to garnish the top.

--PHIL ANDRES

*

1 pound ground beef

1 pound ground pork

4 cups chopped Napa cabbage

1/2 cup chopped cilantro

1/4 cup chopped ginger root

1/2 cup minced green onions

1 tablespoon salt

2 tablespoons Asian chile sauce

2 tablespoons sesame oil

1/4 cup soy sauce

2 eggs, beaten

Hoisin sauce

Combine beef, pork, cabbage, cilantro, ginger, green onions, salt, chile sauce, sesame oil, soy sauce and eggs in bowl and mix well.

Press mixture into 3 well-oiled 2-cup loaf pans or 1 well-oiled 6-cup loaf pan. Bake at 350 degrees, small loaves for 1 hour, large loaf for 90 minutes.

Remove from oven and brush top and sides of loaf or loaves with hoisin sauce.

Makes 8 servings.

Each serving contains about:

246 calories; 1,467 mg sodium; 114 mg cholesterol; 18 grams fat; 2 grams carbohydrates; 19 grams protein; 0.38 gram fiber.

SPICY PORK AND BEEF LOAF WITH THREE-FRUIT COMPOTE

I like meat loaf as much as the next guy, but I like it with a lot of bite. This is the recipe I used before I had my kids; these days, I’ve had to tone it down quite a bit to get them to eat it. Maybe in a few years they’ll develop a taste for the spice and I can go back to making this version.

--MAYI BRADY

*

SPICY PORK AND BEEF LOAF

2 tablespoons butter

1 onion, chopped

3/4 cup chopped carrot

1/4 cup chopped celery

5 cloves garlic, minced

3 teaspoons Worcestershire sauce

3 1/2 teaspoons hot pepper sauce

1/2 cup whipping cream

1/2 cup plus 2 tablespoons catsup

1 pound lean ground beef

1 pound lean ground pork

1 teaspoon dried red chile flakes

1/2 teaspoon cayenne pepper

1/2 teaspoon white pepper

1/2 teaspoon black pepper

1 teaspoon dried thyme

1 tablespoon salt

2 eggs, beaten

1 cup bread crumbs

1 cup chopped tomatoes

Heat butter in large saute pan. Add onion, carrot, celery and garlic. Cook over medium-low heat until vegetables start to soften, about 10 minutes. Stir in 2 teaspoons Worcestershire sauce, 2 teaspoons hot sauce, cream and 1/2 cup catsup, then remove from heat. Allow to cool to room temperature.

Combine ground beef and pork, chile flakes, cayenne, white and black peppers, thyme and salt. Add cooled vegetable mixture, eggs, bread crumbs and tomatoes. Mix thoroughly, but as lightly as possible.

Transfer mixture to lightly oiled jellyroll pan and shape into loaf. Bake 1 hour at 375 degrees.

As loaf bakes, combine remaining 2 tablespoons catsup, 1 1/2 teaspoons hot sauce and 1 teaspoon Worcestershire sauce to make topping. When loaf has baked, brush with topping and return loaf to oven 15 more minutes.

THREE-FRUIT COMPOTE

4 large Granny Smith apples

2 firm pears

3 tablespoons lemon juice

1 tablespoon molasses

1/3 cup brown sugar, packed

1/3 cup water

1/2 cup fresh currants

While meatloaf is cooking, peel, core and coarsely chop apples and pears. Cook in medium saucepan with lemon juice, molasses, brown sugar and water until fruit is very tender, 25 to 30 minutes.

Remove pan from heat and mash fruit with wooden spoon until fairly smooth but still slightly chunky. Stir in fresh currants. Allow to cool to room temperature. Serve with Spicy Pork and Beef Loaf. Makes about 2 1/2 cups.

Makes 6 to 8 servings.

Each of 8 servings contains about:

160 calories; 99 mg sodium; 1 mg cholesterol; 1 gram fat; 38 grams carbohydrates; 2 grams protein; 1.35 grams fiber.

LAMB MEATLOAF WITH LEMON-AND-ROSEMARY ROASTED POTATOES

I had Greek food on the brain when I created this recipe. The Greek combination of lamb and rosemary makes for a delicious meatloaf with a pleasant but not overpowering lamby flavor and all the comforting qualities only meatloaf can provide.

--JANA LIEBLICH

*

3 to 4 baking potatoes

1/4 cup olive oil

3 teaspoons fresh rosemary, finely chopped

Salt, pepper

1/2 pound ground lamb

1/2 pound ground beef

1 egg

1/4 cup dry or fresh breadcrumbs

1 small onion, diced

1 teaspoon Worcestershire sauce

1 (8-ounce) can tomato sauce

1 clove garlic, minced

1 tablespoon parsley, finely chopped

Peel and quarter potatoes, then brush with olive oil and sprinkle with 1 teaspoon rosemary and salt and pepper to taste. Set aside. Combine lamb, beef, egg, breadcrumbs, onion, Worcestershire, tomato sauce, garlic, parsley and remaining 2 teaspoons rosemary in large bowl, mixing thoroughly.

Place mixture into small bread loaf pan or 4-cup capacity round bowl and pat down to form shape.

Unmold into medium-sized roasting pan. Surround with prepared potatoes.

Cover pan with foil and bake at 375 degrees 30 minutes. Uncover pan and continue baking until meatloaf is cooked, 25 to 30 more minutes.

Remove pan from oven and remove loaf from pan, leaving potatoes. Increase oven temperature to 500 degrees and place potatoes back in oven until potatoes are tender and golden brown, 5 to 10 more minutes.

Makes about 6 servings.

Each serving contains about:

283 calories; 374 mg sodium; 75 mg cholesterol; 18 grams fat; 17 grams carbohydrates; 14 grams protein; 0.66 gram fiber.

SOUTHWESTERN CORN TERRINE

This isn’t really a vegetarian dish because gelatin is used as a binder. It’s not really a meatloaf, either, because it doesn’t set up until cold and, well, it doesn’t have meat. The corn terrine needs to be prepared one day before it is to be served. To ensure that the layers bind together, the three mixtures should be the same consistency when molded. Ideally, the segments should be prepared at the same time or in rapid succession.

--PHIL ANDRES

*

GREEN LAYER

1 clove garlic

1 1/2 cups cilantro leaves, blanched

2/3 cup grated Parmesan cheese

1/2 cup pine nuts, toasted

1/2 teaspoon salt

1/4 teaspoon ground black pepper

1/4 cup olive oil

1 1/3 cups vegetable stock

2 tablespoons butter

9 tablespoons white cornmeal

2 eggs

1 (1/4-ounce) package unflavored gelatin

2 tablespoons whipping cream

Puree garlic, cilantro, Parmesan, pine nuts, salt and pepper in bowl of food processor. With machine running, slowly drizzle olive oil into feed tube. Process until mixture is smooth.

Bring vegetable stock and butter to simmer in saucepan. Whisk cornmeal into saucepan in steady stream and cook until thickened, about 5 minutes. Remove from heat. Cool at least 5 minutes and whisk in eggs, gelatin and cream. Fold cilantro puree into cornmeal mixture. Set aside.

BLUE LAYER

1 1/3 cups vegetable stock

1/2 teaspoon salt

2 tablespoons butter

9 tablespoons blue cornmeal

2 eggs

1 (1/4-ounce) package unflavored gelatin

2 tablespoons whipping cream

1 cup corn kernels, cut from cob, roasted

Bring vegetable stock, salt and butter to simmer in saucepan. Whisk blue cornmeal into saucepan in steady stream and cook until thickened, about 5 minutes. Remove from heat. Cool at least 5 minutes and whisk in eggs, gelatin and cream. Fold in roasted corn kernels. Set aside.

YELLOW LAYER

1 1/3 cups vegetable stock

1/2 teaspoon salt

2 tablespoons butter

1/4 teaspoon ground white pepper

1/4 teaspoon ground cumin

1/4 teaspoon ground coriander

9 tablespoons yellow cornmeal

2 eggs

1 (1/4-ounce) package unflavored gelatin

2 tablespoons whipping cream

1/2 cup poached and diced chayote squash

1 red bell pepper, roasted, peeled, seeded and diced

1 Anaheim chile, roasted, peeled, seeded, and diced

Bring vegetable stock, salt, butter, pepper, cumin and coriander to simmer in saucepan. Whisk cornmeal into saucepan in steady stream and cook until thickened, about 5 minutes. Remove from heat. Cool at least 5 minutes and whisk in eggs, gelatin and cream. Fold in squash, red bell pepper and chile.

ASSEMBLY

Vegetable stock, optional

Fresh salsa, optional

Add extra vegetable stock as necessary to each layer to make consistency uniform.

Oil 6-cup tube mold and line with plastic wrap. Fill bottom of mold with Blue Layer and smooth top of mixture with rubber spatula. Spoon Yellow Layer on top of blue and smooth top with spatula. Finally, spoon Green Layer on top of yellow and smooth top with spatula. Cover with oiled parchment paper.

Place mold in large baking pan on oven rack and fill pan with boiling water to make water bath. Bake at 350 degrees until loaf reaches internal temperature of 165 degrees, about 45 minutes. Cool on rack 30 minutes and refrigerate overnight.

To serve, unmold terrine, remove plastic wrap and gently smooth any irregular surfaces. Slice; garnish with fresh salsa.

Makes 8 servings.

Each serving contains about:

478 calories; 762 mg sodium; 204 mg cholesterol; 32 grams fat; 37 grams carbohydrates; 16 grams protein; 1.45 grams fiber.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Kitchen Tip

A quick and easy way to roast corn on the stove top can be found in Mark Miller’s “Great Salsa Book” (Ten Speed Press, 1994). He recommends cutting the kernels from the cob, then dry-roasting them 4 to 5 minutes over high heat in a skillet that has been heated almost to smoking. Keep the kernels no more than two layers deep in the pan and stir occasionally to prevent steaming. The corn is done when it has a nice smoky tinge and flavor.

* Terrine platter from Freehand, Los Angeles. Lamb loaf platter from Geary’s, Benerly Hills