The parent company of Dedham-based Papa Gino's Pizzeria and D'Angelo Grilled Sandwiches announced this morning it has reached an agreement in principle to sell its fast-food chains to a portfolio company and today filed for Chapter 11 bankruptcy protection.

The announcement comes after PGHC Holdings, Inc., stunned employees and customers alike yesterday by abruptly shuttering 95 restaurants without a public explanation.

PGHC said while it regrets the closings they were a necessary step toward addressing the company's debt structure.

PGHC hopes to move "certain team members" from closed restaurants to those which continue to operate throughout New England: 100 Papa Gino's pizzerias and 78 D'Angelo sandwich shops.

The proposed sale to Wynnchurch Capital would require court approval; however, PGHC Holdings, Inc., said in a statement it will solicit competing offers "to maximize the ultimate value of the sale, for both the company and its stakeholders."

Wynnchurch Capital is a middle-market private equity investment firm headquartered in Chicago with $2.2 billion of committed capital under management. Its specialties include restructurings.

Corey Wendland, PGHC's chief financial officer, said, "These were hard decisions, but decisions we believe were absolutely necessary to allow Papa Gino's and D'Angelo Grilled Sandwiches to continue serving New England now and for years to come."

Wendland stressed that PGHC "will continue its long tradition of hosting birthday parties, team celebrations and other neighborhood events."

Papa Gino's was founded in East Boston in 1961. It is the official pizza of the New England Patriots.

D'Angelo's, formerly Ma Riva's Sub Shop, has been in operation since 1967.

Today's bankruptcy filing will enable PGHC to maintain normal business operations, while improving liquidity as it pursues the sale.