NEW YORK — ConAgra Foods is set to become the nation’s biggest maker of store-brand foods, with a $5 billion purchase of Ralcorp that expands its stake in the growing market for cereals, crackers, and other packaged foods sold under private labels.

The deal announced Tuesday caps a year of acquisitions for ConAgra, which makes brands including Banquet, Chef Boyardee, and Marie Callender’s. The company, based in Omaha, also made multiple attempts to buy Ralcorp last year.