Buying packaged mixes means exchanging time for money to many people. To others it means losing control over what goes into what they eat.

For this last group it isn't just a question of wishing to steer clear of additives with strange-sounding names, but also of the best known of all additives, salt and sugar. They are ubiquitous in processed foods.

According to Senate committee report entitled "Dietary Goals of the United States," both sugar and salt consumption should be reduced drastically for health reasons. The report suggests cutting back salt consumption by 50 to 85 per cent and sugar consumption so that it accounts for only 15 per cent of Americans' caloric intake instead of 40 per cent.

Making foods from scratch is one sure way to control the amount of sugar and salt in the diet. But for many the problem of finding the time to cook from scratch sends them scurrying to the supermarket to buy already prepared foods.

Yet from the number of letters and calls received by The Washington Post's Food Section, it is clear that a lot of people would not rely on commercial convenience foods if they only knew how to make similar preparations at home. In the interests of helping them out, here are several recipes that are part of an ongoing do-it-yourself series that began two years ago. ORANGE MOCHA MIX (About 2 cups) 1/2 cup instant coffee powder 1/2 cup cocoa 1/4 cup or more sugar 3/4 cup instant non-fat dry milk powder 1 tablespoon dried orange peel

Stir all the ingredients together and store in a tighly covered container at room temperature. Allow the flavors to blend for at least a week before using.

For each serving, blend 2 tablespoons with 3/4 to 1 cup boiling water. MASTER BAKING MIX (6 cup) 6 cups unbleached flour 2 1/2 tablespoons double-acting baking powder 1 1/2 teaspoons salt 3/4 cup vegetable shortening

Sift dry ingredients together. Cut in shortening until mixture is crumbly. Store in tighly covered container in cupboard.

If butter or margarine is used instead, mix must be stored in refrigerator MARMALADE NUT BREAD (1 loaf) 3 cups Master Baking Mix 1 to 1 1/3 tablespoons sugar 1/2 cup chopped nuts 1 egg, well beaten 2/3 cup milk 1/2 cup orange marmalade

Combine mix with sugar and nuts. Combine egg, milk and marmalade and blend. Add gradually to dry, mixture, mixing only until flour is moistened. Turn into greased 9-by-5-by-3-inch loaf pan and bake at 350 degrees for about 45 minutes. Cool in pan. DATE NUT MUFFINS (1 dozen) 2 cups Master Baking Mix 1/2 cup chopped pitted dates 1/4 chopped nuts 1 egg, well beaten 1/2 to 1 tablespoon sugar 2/3 cup milk

Stir dates and nuts into mix. Stir egg, sugar and milk together. Add, all at once, to dry mixture. Stir only until flour is moistened - the batter will be lumpy. Fill medium-size greased muffin tins 2/3 full. Bake at 425 degrees for 15 to 18 minutes. GROUND BEEF MIX (5 pints) 4 pounds lean ground beef 4 medium onions, chopped 1 cup chopped celery 3 six-ounce cans tomato paste 3 cups water 2 large cloves garlic, minced 1 teaspoon to 1 tablespoon salt 1/2 teaspoon pepper 1 tablespoon oregano 1 tablespoon basil

Brown meat. Add onions and celery and cook until vegetables are tender. Add remaining ingredients and simmer uncovered for 45 minutes to one hour, until mixture is thick. Freeze in portions suitable for your family's use.

Use as is for spaghetti sauce.

To make Sloopy Joes: Combine two cups of ground beef mix with one teaspoon Worcestershire sauce and hot pepper sauce to taste. Serve over buns.

To make Chili: Combine two cups ground beef mix with a 15-ounce can of kidney beans and one tablespoon chili powder. FRENCH DRESSING MIX (Enough for 8 cups dressing) 2 to 4 teaspoons salt 1 tablespoon plus 1 teaspoon paprika 1 tablespoon plus 1 teaspoon dry mustard 1/2 teaspoon black pepper

Combine ingredients and store in tightly covered container at room temperature.

To make French dressing: Combine one tablespoon of mix with 1/4 cup vinegar or lemon juice and 3/4 cup salad oil.

VARIATIONS: For garlic French dressing, add one crushed clove garlic.

For curry French dressing, add 1/4 to 1/2 teaspoon curry powder.

For blue cheese dressing, stir in two teaspoons water with 3/4 cup crumbled blue cheese VINAIGRETTE DRESSING (1 cup) 1 tablespoon French dressing mix 3/4 cup salad oil 1/4 cup vinegar 2 tablespoon finely chopped dill pickle 2 teaspoons chopped chives 1 hard-cooked egg, chopped

Combine oil and vinegar with mix and shake well. Add remaining ingredients and shake again.

The 1975 edition of the "Joy of Cooking" has many do-it-yourself convenience food recipes. here are two. CHILI POWDER 3 tablespoon paprika 1 tablespoon turmeric 1/3 teaspoon cayenne

Pressed garlic to taste

A chili blend may be based on a combination of spices as varied as cumin, coriander, oregano, black pepper, cloves, and sweet and hot red peppers or it may be made up quickly from the combination above. No matter how simple or how complex the mix, use plenty of garlic. CURRY POWDER 1 ounce each ginger, coriander and cardamom 1/4 ounce cayenne 3 ounces turmeric

OR 1 ounce each turmeric, coriander and cumin 1/2 ounce each dry ginger and peppercorns 1/4 ounce each dried hop peppers and fennel seed 1/8 ounce each mustard, poppy seeds, cloves and mace

Mix ingredients together and store in airtight container in cupboard.