Prepared convenience foods have never been a bargain. But their price has risen so much in the last year that there is now even more reason to consider making them at home.

According to the May issue of Consumer Buying Alert, the brainchild of White House consumer adviser Esther Peterson, only the price of meat has risen faster than the price of prepared convenience foods over the past year. What's more, the Buying Alert says prepared foods are not necessarily convenient and don't always contain the same amount of high-protein ingredients found in meals prepared at home. It suggests cooking from scratch when possible.

Frozen TV-type dinners, according to the White House pamphlet, cost 15 to 100 percent more than similar dinners prepared at home. And in most cases, the difference is much greater, since a comparison chart of 24 items in the Buying Alert is based on faulty data provided by the Department of Agriculture.

The White House would have been better off with someone else's research: USDA's methodology leaves a lot to be desired. With rare exceptions, it ignores both cost and nutritional differences between homemade and commercially prepared foods - with the result that convenience foods appear to be a better value than they are.

Assistant Agriculture Secretary Carol Foreman, distressed that her agency did not supply the White House with the correct data, has called the methodology "inappropriate," especially, she said, in light of the fact that "criticism has been made of the department's data in the past on this issue."

Several years ago, USDA began a comparison study of processed foods such as chicken chow mein, beef stew and fried rice with standard home recipes for the same dishes. Its study purposed to show how much cheaper the commercially prepared products were. What it neglected to take into account was the difference between the ingredients. While chicken chow mein in a can might have 3 1/2 ounces of chicken, homemade chicken chow mein had 6 ounces. Canned beef stew might contain 4 ounces of beef; the homewade version had twice as much.

The flaw in USDA results was pointed out in this section more than four years ago. And according to one of the USDA staff working on the continuing project, adjustments have now been made to take these differences into account. But Betty Peterkin, the USDA nutritionist who prepared the table for the White House Buying Alert, included these adjustments only in the case of four TC dinners-fried chicken, haddock, meatloaf and turkey with dressing. Even then, the meatloaf component of the homemade meatloaf dinner was not the same as the frozen prepared product which contained TVP (textured vegetable protein), a meat extender that reduces the cost of ground beef considerably. Other products, such as fish sticks, lasagna and fried rice, were simply weighed and the weight of these products compared to the weight of the home-prepared products.

Foreman said "it's inappropriate that the department did not compare the costs of producing the products from similar recipes . . . Adjustments should have been made."

Midge Shubow, director of public information in Peterson's office, was surprised that a more thorough analysis had not been done.

"I just assumed Peterkin was taking all those things into consideration. I have to rely on her and I would hope USDA lab facilities are doing the best possible job comparing quality and price."

Peterkin said that "the chart is or isn't good depending on what you are using it for. We tried to make clear in the paragraph preceding the entrees."

Peterkin was referring to the caveat which appears instead of a more thorough analysis of the ingredients in the convenience foods, repeated in the Consumer Buying Alert: that many frozen main dishes "contain smaller amounts of desirable high-protein ingredients (such as meat and cheese) than the meals you would prepare yourself." It is a caveat worth remembering.

For example, a 2.6-ounce serving of commercially prepared frozen fish sticks costs 36 cents. Those made at home cost eight cents less. But how much fish is there in the commercially prepared fish stick? How much breading? How much filler? What kinds of fish were used?

Dishes such as fish sticks are hard to compare without knowing the exact amount of each ingredient, which cannot be determined by looking. While it is possible to count the number of peas in butter sauce in one of those plastic pouches, it is not possible to count the shreds of fish. But even in comparing the peas, it is important to know if the homemade recipe contains the same amount of butter, or more. Prepared peas in butter sauce cost 24 cents; made at home they cost 17 cents.

With rare exceptions, it is safe to assume that what you make at home will contain more of the expensive (often synonymous with nutritious) ingredients than what the convenience food counter has to offer.

Keeping that in mind, it is still interesting to compare the prices on the chart offered in the Buying Alert. Except for frozen french fries and potato puffs, homemade costs less.

Which leads Peterson's office to ask the next quesionns: "Do higher costs mean economy-minded shoppers should avoid frozen plate dinners, main dishes, and fancy vegetables and side dishes? The answer depends on your personal time pressures, cooking skills, and kitchens facilities."

Not always. Kitchen facilities aside, the home preparation of many so-called convenience foods takes no more skill than heating up a TV dinner, but you'd never know that from listening to television commercials. Advertising is quite pointed in suggesting that most people are unable to cook properly. Ads for converted and instant rice are perfect examples, suggesting that you, the inept cook, can't prepare rice without having it all gum up-so you should use theirs.

For those who have had doubts about the high cost, lack of taste and nutritional content of prepared convenience foods, it may be more appropriate to ask whether it isn't worth a few extra minutes when you have the time to make your own convenience foods.

If you are willing to set aside an evening or part of one weekend day, you make your own macaroni and cheese, corn muffin mix, frozen popovers, pancake syrup, and set them aside.

If you are willing to examine what really goes into such products as Hamburger Helper, you will be pleasantle surprised to discover that the list of essential ingredients is quite small and you can generally make a far tastier product in the same amount of time it takes to follow the directions on the box.

The recipes below are just a few examples in a continuing series of homemade convenience foods.

The first is the homemade version of a product called Hamburger Helper. It costs about 58 cents to prepare an equivalent amount from scratch, and takes just about the same amount of time as using the boxed product-which costs 83 cents.

By preparing it at home, the following ingredients found in General Mills' Hamburger Helper are eliminated: corn starch, sugar, dried beet (for color), partially hydrogenated soybean oil, spice and natural flavor of unspecified origin, sodium sulfite and BHA to preserve freshness and color.In addition to eliminating some ingredients you may prefer not to eat, you can also control the amount of salt, which is the overwhelming flavoring in the commercial product.

HELP FOR HAMBURGERS-CHILI STYLE

(MAKES 5 ONE CUP SERVINGS) 1 CUP ELBOW MACARONI 3 TABLESPOONS MINCED DRIED ONION 1/4 TEASPOON GARLIC POWDER 1 1/2 TEASPOONS CHILI POWDER SALT AND PEPPER TO TASTE 1/2 OF 6 OUNCE CAN TOMATO PASTE 1 POUND GROUND BEEF

BROWN BEEF IN SKILLET, DRAIN. STIR IN 4 CUPS HOT WATER, AND ALL REMAINING INGREDIENTS; MIX WELL. BRING TO BOIL, STIRRING OCCASIONALLY. REDUCE HEAT AND BOIL GENTLY FOR 12 TO 15 MINUTES, UNTIL MIXTURE IS THICK. SERVE.

NOTE: TO REALLY MAKE THE FLAVOR OF THE DISH, ADD 2 TEASPOONS OF HOMEMADE ITALIAN SEASONING WITH THE OTHER INGREDIENTS.

ZESTY BARBECUE SAUCE

(MAKES 2 1/3 CUPS) 1 CUP FINELY CHOPPED ONION 1/4 CUP OIL 2 CUPS CATSUP 1/4 CUP CIDER VINEGAR 1/4 CUP LEMON JUICE 3 TABLESPOONS WORCESTERSHIRE 2 TABLESPOONS FIRMLY PACKED BROWN SUGAR 2 TABLESPOONS PREPARED MUSTARD 1/4 TO 1/2 TEASPOON HOT PEPPER SAUCE 1 CLOVE GARLIC, CRUSHED 1/2 BAY LEAF 3/4 TEASPOON CHILI POWDER

SAUTE ONION IN HOT OIL UNTIL TENDER. DO NOT BROWN. STIR IN REMAINING INGREDIENTS. BRING TO BOIL. REDUCE HEAT AND SIMMER, UNCOVERED, 20 MINUTES. COOL AND POUR INTO A JAR WITH TIGHT-FITTING COVER. STORE IN REFRIGERATOR. USE FOR POULTRY, BEEF, PORK.

THIS IS MORE EXPENSIVE THAN COMMERCIAL BARBECUE SAUCE-2 CUPS ARE $1.24, WHEREAS 2 CUPS OF OPEN PIT COST 97 CENTS. THAT'S BECAUSE THE HOMEMADE VERSION CONTAINS NO FILLERS OR STRETCHERS. OPEN PIT IS THICKENED WITH MODIFIED TAPIOCA STARCH; SOME OF ITS FLAVOR IS FROM HYDROLIZED SOY PROTEIN. CELLULOSE POWDER GIVES IT BODY. IT ALSO CONTAINS ARTIFICIAL COLOR, CARAMEL COLOR AND ARTIFICIAL FLAVOR. IT'S MAIN INGREDIENT IS CORN SYRUP, FOLLOWED BY DISTILLED VINEGAR, TOMATO PUREE AND SALT. IT IS THINNED WITH WATER. IF YOU WANT TO MAKE THE HOMEMADE BARBECUE SAUCE GO FURTHER, DO AS MANUFACTURERS DO-ADD WATER!

PANCAKE SYRUP

(Makes 2 cups) 2 cups sugar 3/4 cup water 1/2 teaspoon vanilla

Combine ingredients in saucepan and bring to a boil. Boil gently until sugar is completely dissolved. Use as you would any pancake syrup. Store in tightly covered container in cupboard. Keeps indefinitely.

If you want maple flavor, add 2 tablespoons real maple syrup to mixture before boiling. That is five times as much maple syrup as the amount used in those products containing 2 percent maple syrup. Plain sugar syrup sells at 79 cents for 16 ounces; the homemade version is 25 cents. Homemade maple-flavored syrup is 45 cents.

MACARONI AND CHEESE DINNER

(Makes 13 1/2 cups of sauce mix) 1 cup flour 4 cups non fat dry milk 3 1/2 cups grated, dried parmesan cheese 2 teaspoons salt 1 teaspoon nutmeg 2 teaspoons paprika 1 cup butter or margarine, cut in pieces

Mix all dry ingredients together in large bowl. Cut in butter with pastry blender, two forks, or fingers, until mixture is crumbly. Store in airtight container in refrigerator for up to six months, or in freezer for longer. Mixture never freezes solid so it can be scooped out and used without defrosting.

To make macaroni and cheese, for every 1 1/2 cups elbow macaroni, combine 1 cup milk with 1 cup sauce mix. While macaroni is cooking, cook milk and mix until it begins to boil. Reduce heat and cook just below boil, until mixture thickens. Drain macaroni and mix with cheese mixture. This is enough for one main dish serving or for 2 or 3 as side dish.

Note: 2/3 cup water can be substituted for 1 cup milk, if desired.

This macaroni and cheese is not really a substitute for the boxed dinner, because the homemade variety has so much more protein and is so much richer. Again, if you want to recreate the boxed macaroni and cheese dinner, just add more water and cut down on the amount of cheese.

ITALIAN SEASONING MIX 3 tablespoons dried oregano 2 tablespoons dried basil 2 tablespoons dried marjoram 2 tablespoons dried parsley 1 small bay leaf, crumbled

Combine ingredients and use to season oil and vinegar dressings, to mix with flour or bread crumbs as coating mix for meat and poultry, for scrambled eggs or omelette.In other words, just as you would the commercially prepared Italian seasoning, but for less money.

The diferrence between homemade and commercially prepared Italian seasoning is roughly $2 a pound, or about 25 cents for 2 ounces. When you make it yourself you can adjust the proportions to suit your own taste. It keeps as long as any dried herbs. For best storage, keep out of direct sunlight and in cool, dry place.

FREEZER-OVEN-TABLE POPOVERS

(Makes 16 to 18 large) 2 cups flour 1/2 teaspoon salt 2 tablespoons melted butter or margarine 2 cups milk 4 eggs, beaten

Beat together flour, salt, melted butter and milk until smooth. Add eggs, one at a time. Don't overbeat. Grease custard cups, individual souffle dishes or large muffin pans generoulsy with oil. Fill half full with batter-no more or popovers won't rise. Place cups on trays and freeze. When frozen solid, dip cups in warm water quickly so frozen batter can be slipped out. Place batter in plastic bag and seal tightly.

To bake, put frozen batter back into greased containers from which they came. Place on baking sheet and bake at 400 degrres for 35 to 50 minutes, depending on size.

If baked before freezing, follow directions for filling cups then bake at 450 degrees for 15 minutes; reduce heat and bake at 350 degrees for 15 minutes longer, until golden. Serve immediately with lots of butter.

These can be forzen a month.

They look spectacular baked in individual brioche molds.

HOMEMADE CONDENSED MILK

(Makes 2 1/2 cups, or 20 ounces) 1 cup boiling water 6 tablespoons butter 1 cup sugar 2 2/3 cups instant non-fat dry milk

Blend all ingredients thoroughly in blender. Store in refrigerator. Use as you would canned condensed milk, in cooked recipes. Cost for the equivalent of a 14 ounce can of condensed milk is 64 cents; for the commercial product, 99 cents.

CORN MUFFIN MIX

(Makes 10 1/2 cups mix) 4 cups unbleached flour 4 cups yellow cornmeal 3/4 cup sugar 1/4 cup baking powder 1 tablespoon salt

Combine dry ingredients. Cut in shortening with pastry blender, forks or fingers until thoroughly blended. Store in airtight container in cool dry place, up to four months.

CORN MUFFINS

(Makes 12 medium) 2 1/2 cups mix 1 egg 1 cup milk

Lightly beat together egg and milk and stir into mix just enough to blend. Mixture should be lumpy. Spoon into greased muffin tins to fill 2/3 full. Bake at 425 degrees for 15 to 20 minutes, until muffins are golden brown. Serve warm.

To make corn bread, spoon mixture into greased 8 inch square pan and bake at 425 for about 25 minutes.

For a variation on the corn bread, add 1 cup shredded sharp cheddar cheese and 1/4 cup chopped onion to batter.

A package of Flako corn muffins and costs 45 cents. Using homemade mix, 12 muffins cost 19 cents. CAPTION: Illustration, no caption, By Susan Davis for The Washington Post