Itzhak Perlman sought refuge in his favorite cuisine.

"I always go back to food," he explained. "When you cook Chinese food, you put salt and sugar in the same dishes. What could be more different, yet they blend together beautifully. That's how Pinky and I play."

Fine. But there is still something of a contradiction here. World-renowned violin virtuosos don't make a habit of playing duets together. As a group, they are supposed to be tight with the limelight. But there is this mutual admiration society between two of them in full bloom. They even live in the same building on the Upper West Side of Manhattan.

"They're both very secure men who have no need to compete," offered Eugenia Zukerman. "Each thinks that he is the greatest, and they don't worry about it."

That helps explain some of it. Perhaps the fact they both survived the perils of being child prodigies and were born a few miles from each other in Tel Aviv has something to do with it all, too.

But it's a losing battle, really, this search for the bond between Itzhak Perlman and Pinchas Zukerman, because it ultimately is defined in musical terms to which almost none of us is privy.

We can listen to their outrageous borscht-belt humor offstage, we can marvel at their energies, and we can appreciate their warmth.But when Perlman picks up his Stradivarius and Zukerman his Guarneri del Gesu, the two retreat into a world where the rest of us simply can't speak the language.

Perhaps Jimmy Carter, Anwar Sadat or Menachem Begin, three practitioners of rhetoric, can find the words for it tonight, when Perlman and Zukerman bring their music to the South Lawn of the White House.

This performance is, in a way, a sparking coda to the triumphant 11-city American tour they recently completed together which garnered the same raves their European tour did in 1976.

By sheer luck, both artists were free for a few days when the White House contacted them last week. When you consider that each man is booked through 1982, this is remarkable.

"Itsik" and "Pinky" view their attendance at the treaty signing ceremony and their performance at the celebration tonight as a splendid opportunity to be part of history and to share in the joy of the occasion. They are not in the business of making political statements, however, and tonight is no exception.

"I'm a musician, not a politician," Zukerman said in New York Saturday. "I've never wanted to influence anyone because of my violin. This is simply a great occasion to play music, a wonderful time for humanity."

"I'll leave the politics to the politicians," echoed Perlman later that day. "But I do look at this as much more of a giant step for mankind than the one on the moon, though."

Neither man can drop it there.

"I want to tell Sadat that he should set up a recording studio in the pyramids," Zukerman said in his stentorian voice, which is followed by his ubiquitous belly laugh.

"I'd like to play a concert on top of the pyramids," Perlman deadpanned. "Say, I heard a rumor that someone from Disneyland is trying to put up a Plexiglas pyramid next to the real ones. Can you imagine that?"

"They're hysterically funny together," said Eugenia Zuckerman, herself a first-rate flutist who performs with her husband. "But they do things like imitate apes at airports. It can get very embarrassing."

That they often sound as if they toss out one-liners for a living in the Catskills may be a key to their sanity. The tours which take them away from their families up to eight months a year are numbing, particularly for Perlman, who has contended with the crippling affects of polio since he was 4. They can never stop practicing. They can never put their instruments away.

"There is no such thing as leaving the fiddle," Zukerman explained. "You play every day, even when you're on vacation. If you don't, it just hurts more when you get back. You can hear the difference."

Zukerman, who is now 30, picked up a violin at 7 and first learned to play from his father after an abortive experience with the clarinet ("I could never breathe"). He was discovered by Isaac Stern and Pablo Casals when he was 13, and largely through their efforts, he left his family in Israel and came to New York to study under the legendary Ivan Galamian at the Julliard School of Music.

The separation from his family at that age was hard on him, and his music provided the only substance in his life until he met Eugenia at Juilliard and married her before he was 20.He now dotes on her and their two daughters, whom he calls "the Zukettes."

His music had been blossoming along with his romance. At 18, he won the 25th Leventritt International Competition at Carnegie Hall, an honor which cemented his stature as a young giant among performers. He has played the violin and the viola all over the world since then and is now an established veteran on the international circuit.

Perlman, now 33, paved the way, in many respects, for the odyssey which Zukerman would later make from Israel to Juilliard and on to the rarified air beyond.

It was Ed Sullivan, of all people, who was responsible for first bringing Perlman to America. At 13, he played on Sullivan's Sunday night television show along with a number of other Israeli artists invited to perform in this country.

A protege of Isaac Stern, Perlman later returned with his family from Israel expressly to study under Galamian and Dorothy Delay at Juilliard. He won the Leventritt Competition in 1964 and was hailed by many as the leading violinist of his generation. He met his wife at Juilliard and settled on the Upper West Side, where he lives today six floors above Zukerman in an apartment once occupied by Babe Ruth.

If he has an interest outside of music and his family, it is the fight to improve the facilities for the handicapped in the artistic world. "I am familiar with the freight elevators in every concert hall in the United States and Europe," he said. "I want to make the architects more aware of the problems of the handicapped."

Perlman stopped well short of a full-blown speech to discuss Chinese restaurants in New York and to re-enact a scene at one where he and a waiter failed to understand each other throughout a 10-minute exchange.

There should be no shortage of joy at the White House today. That is why Jimmy Carter brought to town the two vital men whom Eugenia Zukerman calls Butch Cassidy and the Sundance Kid. They know how to make the spirits soar, they know how to laugh.