Stouffer Corp., a unit of international food giant Nestle' Co., will take over management of the Mayflower Hotel here on Dec. 1 and make it the "flagship" of Stouffer's growing hotel business.

William Hulett, a former Mayflower manager who took over as Stouffer Hotels president last May, said his company also will become a part owner of the 56-year-old Washington landmark.

For the past decade, the Mayflower has been managed by Westin Hotels (formerly Western International), the hotel subsidiary of UAL Inc., which also owns United Airlines.

Business sources said UAL was interested in continuing to manage the Mayflower only if it could acquire a substantial interest in the strategically located hotel at the corner of Connecticut Avenue and DeSales Street NW, just a block away from the Farragut North subway station.

May-Wash Associates, a group of local business persons that owns the hotel property, apparently wanted to continue primary ownership. Kingdon Gould Jr., one of the principal owners and a spokesman for May-Wash, was out of town yesterday. Information on current ownership of the Mayflower was not immediately available.

Early in 1979, however, Gould (former ambassador to The Netherlands) and his son owned about 35 percent of May-Wash, the estate of William Cohen owned 50 percent, restaurateur Ulysses (Blackie) Auger owned 10 percent and parking lot owner Dominic F. Antonelli owned about one percent.

The change in management will not affect a $25 million modernization of the Mayflower that began in 1979 and is expected to be finished next year, a Stouffer spokesman emphasized. Adding some rooms and expanding others is transforming the Mayflower from an 800-room facility (including 100 as part of suites) to one with 727 guest rooms. When the renovation is completed, it still will be one of the area's largest hotels.

A new restaurant also will be added, and more than 18,000 square feet of public rooms and spaces are being refurbished at the Mayflower, which opened in 1925 on the site of a former convent and which since has been the site of inaugural balls, the late FBI director J. Edgar Hoover's lunches, initial quarters here for diplomats from China and residential apartments.

Stouffer Corp. said it expects to enter into a "joint venture partnership" with May-Wash Associates, but the Stouffer spokesman said he does not know the extent of his company's equity investment. He did say it would be a minority share and that current owners would retain control of the property. Stouffer's management contract runs for 20 years, the company announced.

Currently, Stouffer operates 22 hotels with more than 7,200 rooms in the United States as well as more than 30 hotels in a dozen foreign countries. The Mayflower will be the company's first major downtown hotel in the United States and represents part of Stouffer's corporate goal of doubling its U.S. hotel base by the end of this decade.

Stouffer's only hotel in the Washington area currently is the National Center Hotel in Crystal City, with 400 rooms.