DuPont Co., the Wilmington-based chemical maker that has been selling its businesses since separating from Dow Chemical Co. last spring, is merging its Nutrition and Biosciences group into IFF, a New York food additives giant.

The DuPont food and drug group — which sold $6 billion of products such as artificial sweeteners, seaweed extracts, and the processed bean and soy proteins used in meatless food products — is larger than artificial flavoring and perfumes maker IFF, which had $5 billion in sales last year. But IFF is acting as the acquirer.

IFF, formerly International Flavors & Fragrances, will pay DuPont $7.3 billion in cash, which IFF plans to borrow. The combined companies will be run by IFF boss Andreas Fibig, and IFF designees will initially take more than half the board seats.

The deal values the combined company at $45.4 billion on an enterprise value basis -- stock plus debt -- based on what IFF’s share price was on Friday. DuPont will control more than half the shares.

Shares of IFF closed down 10 percent Monday, or $13.98, at $120 a share. DuPont closed at $64.89, up 14 cents for the day.

Even though DuPont “has stated its intention to use approximately $5 billion of (the sale) proceeds for debt repayment,” the scale of the sale “will likely impact our assessment of the company’s business overall,” said analysts at Moody’s Investor Service in a report to clients. Moody’s is considering cutting DuPont’s credit rating (currently A-) as it reviews the IFF deal.

DuPont Executive Chairman Edward Breen, the Bucks County native who has made a career out of streamlining and selling industrial businesses, will serve as the combined company’s lead independent board director.

IFF said it will shave $300 million in yearly costs from both companies to help pay for the deal. IFF employs around 13,000 at 110 plants. DuPont employs about 10,000 people at 70 locations, including around 650 people in Delaware.

The combined companies also hope to boost sales by $400 million by “cross-selling” products to each other’s customers, Matthew Miller, chemicals analyst at CRFA Research in New York, told clients in a short report. DuPont “has leading positions in enzymes, probiotics and soy proteins.”

“At this time, it remains business as usual. DuPont [Nutrition and Biosciences] and IFF will continue to operate as independent entities. Over the long term, the combined company will create growth opportunities and shareholder value,” said spokesperson Dan Turner.

IFF and Breen have structured the deal as a tax-free merger with DuPont’s subsidiary — a legal arrangement known as a “reverse Morris trust.” Bloomberg LP reported that IFF beat an offer from Irish dairy giant Kerry Group.

The deal has been approved by both boards.

The deal leaves DuPont with automotive, military, medical, water processing, and other specialized materials businesses totaling around $16 billion in yearly sales, down by two-thirds from four years ago, before it merged with Dow Chemical Co. and began selling and spinning off divisions, including a reorganized Dow earlier this year. The shrunken DuPont has been removed from the Dow Jones industrial average after a century as one of America’s benchmark manufacturing giants.

IFF has historic ties to the Philadelphia area, including the Tastepoint artificial vanilla, chocolate, and flavorings business and Tastepoint’s former Henry H. Ottens Manufacturing Co., which IFF bought four years ago.

Tastepoint is headquartered at the former Ottens offices on Holstein Road near Philadelphia International Airport and operates a factory on Decatur Street in Northeast Philadelphia.

Separately, in 1968, IFF helped endow the Monell Chemical Senses Center, a research center in University City, and has since given Monell grants. The center’s leading financial supporter, at the time of its founding and since, is the Ambrose Monell Foundation. (Added Dec. 17)

Under Breen, DuPont has previously spun off its pesticide and genetically modified farm seeds business. It combined with Dow Chemical’s rival farm supply businesses and became Corteva, based in Wilmington, in June, among other deals.

Breen has accelerated a previous DuPont downsizing strategy. The company, which grew rich from sales of military explosives, home and auto plastics, and artificial fabrics such as nylon in the early 1900s, seemed to lose its ability to invent enough profitable new products as global population growth slowed and world demand for chemicals plateaued recent years.

Earlier in the 2010s, DuPont spun off its car-paints business (Axalta, based in Philadelphia). It also combined a group of chemical plants, including both popular products such as the white pigment titanium dioxide, plus a lot of the company’s old environmental liabilities, into another company, Chemours, now based in a chunk of DuPont’s former headquarters in downtown Wilmington. (Story updated Dec. 30)