As foodservice operators look for innovative ways to differentiate themselves in a fiercely competitive marketplace, many are taking a fresh look at that old menu stalwart, the sandwich.

For years, a predictable assortment of conventional sandwich offerings could be counted upon to generate revenue as consumers remained faithful to a small selection of dependable menu favorites. More recently, though, adventurous customers have demonstrated they are looking for more freedom and something that packs a little more excitement when it comes to placing their sandwich order.

The trend “starts with an overarching need by the consumer to have the ability to customize their sandwiches,” says Darren Tristano, executive vice president of Technomic Inc. in Chicago. “Ultimately, they want the sandwiches made their way.”

As a result, operators are upgrading all components of the sandwich — including the filling, the preparation method, produce accompaniments, cheeses, condiments and, increasingly, the bread.

“Consumers have come to expect more,” Tristano says. “We're seeing an increasing need for innovation around all elements of the sandwich, but the bread carrier has gotten more attention lately.”

Over the past several years, operators have launched a new wave of artisan-quality bread carriers that includes various types of bagels, multigrain breads, brioche ciabatta, flatbreads, baguettes, croissants, tortillas and even waffles — as popularized at the Southern California fast-casual sandwich chain, Bruxië, and more recently debuted by Taco Bell in its aggressive push to grab a piece of the breakfast market.

Pretzel bread also has emerged as one of the frontrunners in the race to introduce new and innovative bread varieties, as chains like Blimpie, Wendy's, Sonic and Dunkin' Donuts showcase a range of permanent sandwiches and LTOs. According to researcher Datassential, the incidence of pretzel bread appearing on sandwich menus rose 36 percent between 2011 and 2012.

Such artisan-quality breads “create a more premium and gourmet position that allows operators to charge higher price points,” Tristano says.

Meanwhile, menumakers continue explore opportunities for all elements of a sandwich — particularly the filling, or main protein. While Technomic has found that the sandwich protein line up has not shifted much in the limited service restaurant category, turkey nevertheless continues to play an important role. In the full-service restaurant category, Technomic's 2012 Consumer Trend Report on sandwiches finds that turkey increased its incidence on menus from 14.5 percent in 2009 to 15.3 percent in 2011.

Consumers generally see turkey as having a health halo, which has become more important in the food-away-from-home experience. At the same time, many operators cite turkey's versatility and its ability to marry well with a wide range of other ingredients — notably breads.

Recent examples include Panera Bread's Sierra Turkey Sandwich, with smoked turkey breast, chipotle mayo, field greens, and red onions on Asiago cheese focaccia; Au Bon Pain's Turkey Club with Cheddar, applewood-smoked bacon, tomatoes, mesclun and mayo on toasted country white; and Subway's LTO, Jalapeño Cheddar Bread, which was available as an option with all orders and fillings.

Blimpie, the 600-unit sandwich chain based in Scottsdale, Ariz., and owned by Kahala Corp., has been steadily evolving its menu to accommodate changing tastes over the past decade, says Steven Evans, vice president of marketing. The chain introduced its Panini Grilled Subs category with ciabatta bread in 2003 and expanded the line with pretzel bread in 2009, making Blimpie — which is celebrating its 50th anniversary this year — one of the first sandwich brands to offer it.

Turkey ranks high among Blimpie's hot and cold subs, Evans says. The No. 2 seller for the six-item panini subs line is the Turkey, Bacon and Cheddar sandwich, which includes oven-roasted turkey, bacon, smoked Cheddar, tomatoes and spicy mustard, served on a choice of either ciabatta or pretzel bread. Originally introduced as an LTO, the sandwich is now a permanent menu fixture.

“Turkey goes with anything,” says Julie Rogers, senior director of product development. “And people are loving bacon now. Turkey and bacon together are guaranteed to sell well.”

The pairing of turkey and bacon also appears in Blimpie's wraps category. Called the Southwestern, the sandwich is ordered with spicy chipotle mayonnaise by most customers, Evans says.

The second-place position on Blimpie's cold deli subs line also is occupied by a turkey and provolone sandwich.

Caribou Coffee, the 360-unit bakery-café chain,  also is among the brands that are upscaling their sandwich line at lunch. Currently in the second phase of a three-phase rollout, the Minneapolis-based Caribou is replacing an earlier grilled cheese sandwich  line with several new selections.

Bri Bauer, Caribou's partnership and public relations manager, says, “The sandwiches offer the same premium standards as our coffee. We want  people who come in for breakfast to come back at lunch.”

Two of Caribou's new lunch sandwiches feature turkey on different bread types. The Roast Turkey Ciabatta includes oven-roasted turkey breast with mozzarella and aioli-pesto spread, served on a sundried tomato-basil ciabatta. The Turkey Brie Pepper Jam on Baguette combines oven-roasted turkey breast with brie and pepper jam, served on baquette roll.

“The turkey tested well paired with the breads Caribou wanted to offer,” Bauer says. “And customer feed back was very positive.”

The third phase of the rollout will include ready-to-eat green salads and wraps.

Bruegger's Bagel Bakery, the bakery-cafe chain based in Burlington, Vt., also is looking to strengthen its lunch menu with several new premium sandwiches. In addition to testing croissants in Boston, the chain also has in test in the Minneapolis marketplace a thicker cut, fire-braised turkey that, if successful, could be rolled out chainwide. The fire-braised turkey is being served on a ciabatta roll with brie, arugula and lemon-cranberry mustard.

The new, more premium turkey also is being offered with fig spread, plain cream cheese, arugula, cucumber and champagne vinaigrette. It is served on a sprouted whole grain roll, which is offers a good choice for individuals on a low-glycemic diet.

Turkey, in fact, ranks as Bruegger's best-selling protein at lunch, Kadylak says. The brand also offers two other sandwiches — Herby Turkey, which includes roasted turkey, light her garlic cream cheese, sundried tomato spread, lettuce and red onions served on a bagel; Turkey Chipotle Club, with turkey, peppered bacon, chipotle mayonnaise, lettuce and tomatoes served on honey-wheat bread.

“Guests are looking for something exciting and memorable,” Kadylak says.