CAMDEN, N.J. — Food companies tinker with the signature products in their portfolios at their own risk — and few products are as classic as Campbell’s chicken noodle soup.

Now, Campbell Soup is altering its famous broth. The new recipe appears first in a limited-edition line in cans festooned with Chewbacca and other figures from the coming “Star Wars” film. The new version of its chicken noodle soup contains 20 ingredients, most of which can be found in the average home kitchen, compared with 30 in its previous incarnation (sold last year in cans featuring the Avengers).

“We’re closing the gap between the kitchen and our plants,” said Denise M. Morrison, chief executive of Campbell.

Under Ms. Morrison’s leadership, which began in 2011, Campbell has moved quickly to address changing trends in food and to try to stanch the gradual decline in unit sales, a measurement of the number of cans of soup sold.