Doritos, M&M's, Pepsi: This is the vending machine of today.

Popping beans, eat-it-all melons, carbonated milk: That may well be part of the automated eatery of tomorrow.

In research labs around the country, a host of unusual products -- from carbonated milk to pickled hot dogs -- are being developed by scientists eager to create new favorites for the American palate.

Most of their experiments are designed to produce better tasting fruits and vegetables, higher yielding crops and more nutritious foods. In numerous labs, for instance, scientists have been diligently breeding corn to create sweeter, longer-lasting ears. Tomatoes, too, are the subject of vast experiments, all aimed at coming up with high-quality fruit, year-round. Meanwhile, scores of scientists are studying a variety of ways to reduce the fat in meat and the cholesterol in eggs.

In the process of devising new and improved products, however, several scientists have come up with some out-of-the-ordinary creations that could become staples in kitchens and vending machines in the not-too-distant future.

Take carbonated milk. Even to milk lovers, the mere idea sends bubbles up the spine. But the concept seems quite logical -- and tasty -- to Ranjit S. Kadan, a research food technologist at the Untied States Department of Agriculture's Southern Regional Research Center in New Orleans.

"The idea came about five years ago when we had a large surplus of nonfat dry milk, more than one billion pounds, in stock," Kadan recalls. The milk "gets spoiled after some time, so it has to be given away. We thought maybe we can do something with this product so it can be used, with no burden to the government."

The specific idea of carbonated milk came from Kadan's own home where he noticed that his teenage daughter had abandoned milk for soda. "Why not do the same thing to milk and carbonate it?" to make it more appealing to the young, Kadan thought. "So that's what we did," he said. But first the USDA researcher had to figure out how to add carbon dioxide without causing the milk to separate.

Now, Kadan says he believes he's devised a pleasing alternative to the drink that, as the television ad notes, "does a body good." According to Kadan, "one reason people don't like milk is that it has a very bland taste and the milk protein coats your tongue and leaves a blah taste." Thanks to carbonation, however, his drink -- touched up with strawberry, cherry or other fruit flavors -- "leaves a clean, tingling aftertaste," the proud inventor claims.

Flavoring does have its drawbacks, however, Kadan notes. The strawberry milk, for instance, looks like Pepto Bismol, discouraging some would-be drinkers from even trying the concoction.

Even so, "representatives from almost all major food companies have come here to look at the technology ... It's ready to go right now" if the milk is to be sold refrigerated, Kadan says. It will be another year, however, before the technology is perfected to the point that carbonated milk can be sold at room temperature in the beverage aisle alongside Pepsi or Coke.

While Kadan worked on carbonated milk, another USDA scientist created a frozen milk concentrate that can be used much like frozen orange juice.

George Bookwalter, a research food technologist at the USDA's research plant in Peoria, came up with the idea as a result of the Chernobyl nuclear accident. When international-aid officials asked Bookwalter what products the United States could ship into Chernobyl, Bookwalter suggested nonfat dry milk. But the officials complained that nonfat dry milk wouldn't provide the fat and calories needed by young children.

"I went to the lab to see what I could do," Bookwalter says. "I found there was a way to add oil without any type of emulsifier or anything like that" to form a milk concentrate which, when diluted with water, would contain up to 4 percent fat. In the process, Bookwalter realized that he could take the newly created concentrate and freeze it to produce a commercial product that could be marketed and used just like frozen concentrated fruit juices. Mix an eight-ounce can of concentrate with three cups of water and, voila`, a quart of milk.

Although Bookwalter does not expect his product to become an everyday staple, he predicts it will become a handy item, especially for cooks and mothers of young children, neither wanting to be caught short. "It's convenient; you can store it in the freezer and take it out when you are ready to use it." At the same time, Bookwalter notes, his frozen creation is a boon to milk drinkers who want to limit their fat and cholesterol because his frozen milk has a very small amount of cholesterol and contains polyunsaturated fat instead of saturated fat found in regular milk. But, Bookwalter says, it still tastes like regular milk.

"A lot of companies have expressed an interest in it," he says, adding that one frozen food manufacturer has applied for a license to use the now-patented process. Bookwalter has also applied for a patent for a low-cholesterol whipped topping made from his frozen milk concentrate. The topping is made by thawing the concentrate, adding flavorings and blending.

While Bookwalter and Kadan both have been seeking new uses for an old and well-known product, plant physiologist Stephen C. Spaeth has had a markedly harder task in simply trying to get another age-old, but little known, product to grow in the U.S.

The product is the Andean popping bean, called nunåa. An ancient crop of the Incas -- grown near the equator in the high elevations of Peru, Bolivia and Ecuador -- these colorful beans burst and expand when heated rapidly, much like popcorn. With a taste similar to roasted peanuts, but without all the fattening oil, popping beans could be an important find to the snacking world, says Spaeth who works at the USDA lab in Pullman, Wash.

But first, Spaeth and his colleagues must figure out how to grow the beans in the lower elevations of the U.S. The plants have been successfully cultivated in a hothouse, but outside, they fail to flower and produce beans. The reason is simple, Spaeth says. The plants need short days to flower, but here, the days are longer than the nights during the growing season.

For the past two years, Spaeth has been trying to transfer the genes that regulate the popping characteristic into similar bean species. "We have two plants we have tested but so far they do not pop. That means the popping trait is not regulated by a single gene, which means it will increase the amount of time required for a successful breeding program -- perhaps as long as 10 years," Spaeth says.

In other laboratories, similar breeding programs are underway, but unlike Spaeth's work, these programs center on products already well-known here. In these cases, scientists are trying to create new breeds to make these foods even more popular with consumers.

Of these, perhaps one of the most unusual is the eat-it-all melon being developed by Perry Nugent, a horticulturist at the USDA's vegetable laboratory in Charleston, S.C.

For years, melon-expert Nugent had been toying with the idea of breeding a small melon that could be easily consumed in one sitting. But it wasn't until 1986, when a vending-machine official approached him at an international horticultural meeting, that he actively began to consider the prospect. "The man asked me, 'Why can't you develop a cantaloupe that would fit into a machine?' " Nugent recalls.

Within a year, Nugent started his breeding program. His aim was not only to make a small melon that would fit into a slotted machine, but also one that could be eaten like an apple -- rind and all. The seeds either would have to be edible or have a single pit that would be easy to discard.

The idea was not entirely off-the-wall, Nugent explains. After all, there is a casaba melon with an edible rind, and there are scores of small melons, some down to the size of cherry tomatoes, that can be found all over the world. But Nugent notes, "their quality is not very good."

Now in the fourth generation of plants, Nugent says he is "seeing some things I like, some things I don't like." On the one hand, he has gotten the fruit down to the size of an apple, with a fairly good quality. He has also produced a plant with a high yield -- 120 small melons in a single season. Unfortunately, the taste wasn't very good. "We have to taste a lot that aren't very good. Some are downright terrible," he notes.

Still, Nugent remains confident about his mission, noting that his biggest challenge now is to produce a fruit with edible seeds. "It looks like several years -- four to five -- before a seed company can look at this."

Two University of Florida professors have been more successful in developing miniature tomato plants for the apartment dweller. Called "Micro-Tom," these plants grow to about six inches in height and produce tomatoes an inch in diameter. In development for seven years, the seeds are expected to be available commercially later this winter.

The plant began as an attempt by J.W. Scott and Brent Harbaugh to breed an ornamental plant that also would have value as an edible crop.

"Our concept was that the whole plant had to be miniature -- the stem, leaves, fruit and all," says Harbaugh. "We were trying to make a plant small enough that homeowners could grow it on the windowsill or on balconies. Our hope is that three of these plants will be grown in a five-inch hanging basket" that could be hung above the kitchen sink. Then, when the tomatoes ripen, it's only a quick, short toss into the salad. The taste, says Harbaugh, is "like a homegrown tomato, with a real tomato flavor and less sweet than a cherry tomato."

What with milk being turned into a carbonated drink and tomatoes being shrunk to the size of marbles, it should come as no surprise that another scientist is tampering with the all-American hot dog.

Jay B. Fox, a food chemist at the USDA's Philadelphia laboratory, has created a pickled hot dog that could last for a long time at room temperature. Pickling any product stops bacteria and mold, but until recently it was impossible to pickle hot dogs without them turning to mush.

After some experimentation, however, Fox discovered that by using the thickening agent xanthan gum -- produced through the bacterial fermentation of sugar -- hot dogs could be pickled and remain firm enough to be stored at room temperature for months at a time.

The pickled hot dog, Fox says, tastes "like a dill pickle but with a pickled meat flavor. If you happen to like pickled flavors, you'll like this," he says. "I have carried them on backpacking trips," he adds.

Now, Fox is trying to find companies that may be interested in using his process to sell pickled hot dogs commercially.

What's next? With increasing emphasis on the environment, some scientists are turning their attention to the containers in which food is stored and served. At the Rochester Institute of Technology, for instance, professors and students are exploring edible containers made out of cellulose. At this point it's unclear whether the crunchy containers would be flavored or not.

In either case, it's not such an off-the-wall idea, says R.I.T spokeswoman Laurie Maynard. "The Egyptians used food and other things wrapped in palm leaves. Those palm leaves would then be steamed and eaten. So it's an old idea, being recycled, just like fashion."