Imagine spaghetti without tomato sauce, Hungarian goulash without paprika. Even worse, consider a world without chocolate cake or an on-the-run cheeseburger with fries. Such would be the dire straits of the culinary world if the Old World explorers had never encountered the Americas. No matter what you may think of Columbus -- whether you laud his courage or deplore his voyages -- there is at least one result in which virtually all cultures of the world can take daily delight.

"The best thing that came out of Columbus is that we all eat better," says Carolyn Margolis, assistant director of Quincentenary programs for the Smithsonian's National Museum of Natural History. "The Europeans didn't have chocolate or vanilla. The natives in America didn't have cheese or milk. So there couldn't have been hamburgers with french fries. Chili peppers had never been eaten by Europeans before. Suddenly Hungarians had paprika.

"I don't think you can sit down to the table today and have a meal that's not the result of these two worlds coming together. Everybody got a new diet from it -- a more interesting diet out of it. There was not a cuisine in the world that was not affected," Margolis says. That is one of the chief points Margolis and her colleagues strive to make in the "Seeds of Change" exhibit at the Smithsonian's National Museum of Natural History. Opening Saturday and running until April 1993, the $2.8 million exhibit is the museum's lengthiest and largest temporary show ever.

One of several special exhibits planned by the Smithsonian to commemorate Columbus' 1492 voyage, "Seeds of Change" offers numerous opportunities for the culinary world to celebrate. Seminars, cookbooks, magazine articles, cooking classes and, of course, feasts have been planned to highlight the exchange of food that occurred as a consequence of the Europeans arrival in the New World.

In fact, last weekend -- even before the exhibit opened -- the Smithsonian held a two-day symposium "Good as Gold," where a number of well-known culinary historians and writers discussed the foods the Americas gave the world.

"It is a key moment, just as the bicentennial was," to the food world, says Michael Batterberry, founding editor and associate publisher of Food Arts magazine and one of the panelists at last weekend's seminar. "The bicentennial made people focus on American roots and that extended to American foods -- regional foods which had always had second class citizenship in restaurants, at least in the public's mind," Batterberry says. "Now, we're on to the same sort of thing, looking at the food of this hemisphere. The amount of literature that the quincentennial is engendering is going to make people think about the foods of the Americas in a more concerted way."

What's more, notes Batterberry, the culinary festivities "are very timely because these foods dovetail with a lot of the nutritional guidelines {offered} in recent months and years. A lot of these foods are grains, beans and legumes; protein plays a less dominant role than it does in a meat and potatoes society."

Until recently, when it came to studying the impact of Columbus's trips, most attention was centered on the gold and silver that the Spanish government gained. But that was not what made Spain so powerful, says historian William H. McNeill in the book, "Seeds of Change" (Smithsonian Institution Press, 1991, $39.95 for the hardback, $24.95 for the paperback), that accompanies the exhibit.

Instead, says McNeill, it "was a change that historians have often overlooked: The spread of American food crops to Europe, Asia and Africa. These crops included maize, potatoes, sweet potatoes, tomatoes, peanuts, manioc, cacao, as well as various kinds of peppers, beans and squashes. All of them were totally unknown outside of the Americas before the time of Columbus. If you imagine the Italians without tomatoes, the Chinese without sweet potatoes, the Africans without maize, and the Irish, Germans and Russians without potatoes to eat, the importance of American food crops becomes self-evident."

Indeed, McNeill points out, together with rice and wheat, potatoes and corn are the four chief staples of the human diet. That's why potatoes and corn were chosen as two of the five seeds highlighted in the Smithsonian exhibit. (Tomatoes and tobacco were runners-up).

The other three "seeds" of the exhibit were ones that came from Europe and forever changed the Americas: disease, the horse and sugar.

Together, these three seeds nearly annihilated the indigenous peoples, Margolis says. "It was, for the most part, not anything anyone did purposely. But it's what happens when two isolated groups come in contact."

Diseases such as smallpox and bubonic plague had not been in the Americas until the European explorers arrived. So the native population had no immunity to fend off spreading epidemics, making it all the easier for the Europeans, especially the Spanish conquistadors, to defeat the Aztec and Inca civilizations.

The horse, on the other hand, ultimately proved to be a great boon and cultural symbol to the Indian tribes on the North American plains. Even so, notes Margolis, the horse is "what the Europeans used to conquer and colonize" the native populations.

Then there's sugar, which the Europeans brought to the West Indies, where the climate enabled it to grow quickly and thrive. "Next to disease {it was} perhaps the most detrimental contribution of the Old World to the New," writes Herman J. Viola, director of the Quincentenary Programs for the National Museum of Natural History. "Sugarcane merits censure because it harmed both man and the environment." The labor-intensive sugarcane plantations not only replaced the rain forests but also led to the mass importation of African slaves, Viola notes.

Corn and potatoes, on the other hand, had a more positive effect in the worlds to which they were introduced.

"The labor force that sustained Europe's intensified urban activities ... could not have been fed without them," writes McNeill. "The flood of emigrants who peopled the Americas and other lands overseas could not have survived infancy without the extra calories that came from potatoes and maize."

In fact, McNeill points out, the potato helped many citizens survive wars and tyrannical governments. Potatoes "could be left in the ground and dug only as needed for daily consumption. Soldiers usually could not take the time to dig a field to get their food, and they certainly would never do so if stores of grain were ready and waiting in neighboring barns. Anyone with enough potatoes in the ground could survive the most ruthless wartime requisitioning. Even if all the grain was taken, food remained at hand to tide over the crisis."

Today, corn and the potato are integral parts of the European and Asian diets. No wonder then, that the entrance to the exhibit features corn -- 14,000 ears of it, to be precise -- in the colorful, 42-foot-high Spanish-style doorway. Later on, two dioramas of Native Americans portray the legacy of corn and potatoes in the New World. These are surrounded by artifacts, both old and new, signifying the major contribution these two crops have made to the American societies.

It is in the "Treasure Room," however, where the significance of the New World's food becomes clear. In the center of this plushly carpeted room, gold and silver pre-Columbian objects are on display. "These are objects of craftsmanship," says Margolis. "While they are beautiful, they did not have as much of a lasting impact as the New World foods" that are pictured in early engravings hung neatly around the pre-Columbian treasures.

"One years's crop of potatoes is worth more than all the gold and silver the Spanish took out of the New World," says Margolis. "So these," says Margolis, pointing to the engravings of sweet peppers, vanilla, watermelon, squash, cacao, tomatoes and sweet potatoes "are the true treasures of the New World."