EVENTUALLY our leading scientific minds will discover that homemade ice cream prevents the common cold as well as significantly retarding the process of aging.

Unfortunately, this breakthrough in nutritional information probably will not take place in this century. So instead, here is some advice on ice cream makers. (Forgive me, Mr. Pritikin, wherever you are.)

All ice cream making machines consist of a can-like container that holds the ingredients. In addition, there is a series of spatula devices, called dashers, which continually churcn the mixture during the freezing period, thereby preventing the formation of ice crystals and ensuring a smooth, even texture in the final product. The dashers can be turned by a motor or by hand. Another essential element, a method for reducing the temperature surrounding the ingredient container, takes one of two forms. It can be part of the ice-cream maker itself, like the wooden bucket containing crushed ice and rock salt with the ice cream cannister in the center. Or the freezing agent can be external to the machine-for example, the freezing compartment of a refrigerator.

The oldest style still available is the pine-bucket model with a hand-cranked dasher. The ingredients go into a tin-coated steel can and a set of tin-coated cast-iron dashers go into the ingredients. A cover goes on the cannister and a metal bridge clamps in place across the top of the tub, holding the dashers, crank and cannister in place. The tin coating is important because it will not interact with the food. In addition, the tin and steel will resist the corrosive quality of the rock salt.

The ice used with this model must be crushed by machine at the ice factory or at home, utilizing a canvas or burlap bag and a mallet. The ice is then mixed with rock salt and placed in the space between the wooden bucket and the cannister. Be careful to protect your hands with waterproof gloves when handling the ice-and-rock-salt mixture. It can produce a chemical burn.

The Rolls Royce of the hand-cranked ice cream freezers are those made by White Mountain Freezer, Inc., in Winchendon, Mass. They come with two-, four-, six-, eight-, 10- and 20-quart capacity. The convenient six-quart model retails for about $80.

White Mountain, which has been manufacturing ice cream freezers for more than 100 years, also produces an electrified wooden tub model. Its design and operation are identical to the muscle-building manual version, with the exception that an electric motor, which will operate on either alternating or direct current, replaces the hand-crank. Ther are four-quart retailing for about $120.

A significant advance in home ice cream making technology took place a bit more than a year ago when Waring introduced its Ice Cream Parlor. The Waring units is based on the old-style tub, but the motor is in the base. The ice-and-salt bucket sits atop the motor, removable for easy cleaning. Most important, the machine works with four trays of ice cubes (the type you normally find in the average refrigerator's freezer compartment) and one 16-ounce container of regular table salt. It turns off automatically when the ice-cream is finished, which takes between 30 and 45 minutes. It will make two quarts of ice-cream sherbet, frozen yogurt or just about any other frozen dessert. The list price is $39.95. (A similar model with an acceptable test record is made by Norelco at $34.95.)

Salton manufacturs a machine that needs no ice of salt of any kind. It has a tinned-steel, one-quart can with a plastic lid and dashers, and a top-mounted motor. The entire unit goes into a freezer. It should be put in a freezer area that maintains a constant temperature of two degrees or below. A 7 1/2-foot cord, covered with a protective woven-wire braid, passes out of the closed freezer door. Circulation of warm air into the freezer is prevented by the pressure of the door's rubber guard around the cord. (The wall outlet must accept a three-pronged plug and be grounded in order to use this machine safely.)

The freezing time required can easily run over two hours, compared less than one hour with the ice-and-salt method. The one-quart capacity is too small for more than just a few servings, so watch your guest list. It doesn't use much electricity to function and it's easy to clean. It generally has a price of $21.95

S.E.B, a large Frech electrical-products company, also produces an in-the-freezer model. Similar in function to the Salton unit, it produces ice cream in a donut-shaped ring with a diameter of approximately 8 inches. It is not widely distributed, and it is slow; but for many years I used it because the result was so attractive. I would make three or four servings at a time, wrap them tightly and store them in my freezer. When I needed a fast but elegant desert, I would unwrap one and fill the hole with fruits and brandy.

KitchenAid manufactures an ice cream-making attachment for their K5A mixer. Unfortunately, it does not function as well as the other attachments for that product and I cannot honestly recommend it.

If the White Mountain products are the Rolls Royce of ice-cream makers, then the electric Minigel at $650, must be the Hispano-suiza. It has an 18-by-12-inch base and is 14 inches high. There is a bowl indentation built into the top surface with the dashers inside. The bowl is permanently surrounded by a quantity of freon-the gas used to reduce the temperature in many freezers and refrigerators. Put the ingredients into the bowl, cover them with the see-through lid, throw on the switch and 25 minutes later you have ice cream, sorbet or sherbet. I first saw the Minigel in James Beard's kitchen and over the past two years he has lauded its production.

Bear in mind that your homemade ice-cream will be free of neutralizers, preservatives, stablilizers and artificial flavors. And it will not be highly aerated, like some commercial ice creams which are sold by volume, not by weight. Adding air gives the manufacturers more ice cream for less cost.

But homemade ice cream is not cheap. It will be richer, thicker and heavier; but heavy cream, sugar, eggs and fresh fruits are not low-cost ingredients. Still . . . the weather is getting rather warm and this not-so-young man's thoughts turn to frozen desserts, with the kind of taste, texture and purity that can only be found in the homemade variety. CAPTION: Illustration, no caption